Wednesday, 9 August 2017

After Es, why not try meteor scatter with MSK144?

As the Es season starts to wind down, my mind turns to meteor scatter.

Anybody on the VHF bands who uses modes like JT65, PSK, JT9 or FT8 already has all of the basic system to use the MSK144 mode.
2 metre band MSK144 activity seen on PSK reporter on 9 August 2017
When I was first licensed meteor scatter seemed exotic and very difficult. So it was in the 1970s. Only the kings of the hobby tried meteor scatter. I also became aware that these stations tended to use pretty high power. The text books suggested that commercial meteor scatter stations used hundreds of kilowatts and huge high gain antennas. So it looked to be out of my league.

The real game changer for me was the arrival of personal computers running data modes via audio tones. We now have the WSJT-X suite which offers MSK144, the latest solution to the meteor scatter mode battery. MSK144 can also be found on MSHV, and both these suites can be downloaded via the links on the right of this page.

Now anyone who is used to the other WSJT-X modes can try meteor scatter. My long held view that lots of power and large antennas were needed has been proved wrong. Whilst a simple dipole or loop is not going to work, I found that using about 100 Watts and an HB9CV got me round Europe reasonably well. A few simple improvements - going to 200W and a three element yagi certainly helped a bit more - but not too much.

As it says in the WSJT-X User Guide:-

Meteor-scatter QSOs can be made any time on the VHF bands at distances up to about 2100 km (1300 miles). Completing a QSO takes longer in the evening than in the morning, longer at higher frequencies, and longer at distances close to the upper limit. But with patience, 100 Watts or more, and a single yagi it can usually be done.

Not just the modes have changed over the years, so have the radios. These days most rigs are rated at full power output for FM use. They often have several multi-speed fans. MSK144 has 15 second tx segments which makes appreciable difference compared with the longer tx periods we used to use. This gives two rx cooling segments in each minute, which the rigs seem much happier with. Frequency stability has improved out of all recognition, though I have added the optional TXCOs to my Yaesu and Kenwood rigs.

You can listen to the VHF bands and hear meteor "pings" - short bursts of scattered radio signals. They are not all weak. At their peak periods pings can be remarkably long, up to a  minute or two and come in sustained bursts. However, the more common individual ones are not so strong and last for fraction of a second. In this situation, adding more power or pre-amplification does very little for communication during the peak moment but might lengthen the time you can hear the signal as it fades away. What MSK144 does is to further improve the ability of data modes to cram the necessary information into a short enough time to be decoded at the other end. 

There is a lot of variation in meteor activity between times of the year and also between times of the day. The meteors strike the Earth every day, but there are periods when large groups arrive over a period of a day or so, and these are called "meteor showers". Despite what you hear, you can work meteor scatter at any time of the year, not just on the few days of the meteor showers. It gets harder between mid January and April, but it can still be done. And generally the period between 06:00 and 12:00 local time is probably best.

So all this means that anybody who can work other data modes can probably try meteor scatter. However, meteor scatter requires a different operating technique. Whilst there is a lot of complexity about the mechanics of communicating via meteors, and a lot to do with the meteors themselves, the purpose of this posting surrounds getting started. I am going assume that you know or can read up about the concept of meteors and scatter, so I am not going to cover that.

What I am saying is based on the IARU Region 1 meteor scatter rules - other parts of the world will have their own systems which may be different.

Here are my 11 key suggestions for converting to meteor scatter:-

1) Be patient

There is huge variability in the numbers of particles hitting the Earth. Breaking this down annually, the number is so low between mid-January and the end of March that I often work almost nobody. By comparison the peaks during the "showers" can provide contacts almost continuously

It takes patience to get the right conditions to pass the necessary information back and forth to constitute a QSO. MSK144 is a masterpiece of software design in which the data stream is carefully honed to convey the information quickly enough to get through a very short opportunity while the ion trail caused by the meteor is in the right place. MSK144 is very good at it, but you still need the meteors to be in the right place, so often you have to wait.

During a shower burst you can have a quick QSO. At more normal times you might send CQ for ten minutes and hear nothing. Then you hear a reply during a short ping on the 10th minute. You send your report for ten more minutes and hear nothing until the end of another (say) seven minutes when you get your report back.

So you have to be ready to just keep sending your message and waiting to receive the other one. It can be a bit frustrating and when you are neurotic (like some we could mention) you begin to think that it is all your fault; perhaps your antenna has collapsed, or you have drifted off frequency, or gone into a trance.

It stands to reason that QSOs tend to be longer at times when there are fewer meteor pings. So during showers it is much easier to get replies. The daily cycle runs so that meteor strikes are at their peak around 06:00 local times and least around 18:00. But it is still possible to work stations at all times if you have the time to devote to it.

2) Stick to the correct segment.
By convention, in Region 1 those beaming East or South transmit "second". This means that they listen for the first 15 period between 0 and 15 seconds), transmit in the second (15-30), then of course listen in the next (30-45) and transmit in the next (45-60). This is indicated in that they listen in the red quadrants and transmit in the green below:-
The IARU Region 1 meteor scatter minute
Obviously the station they are working to the East of them is beaming West and therefore doing the opposite. Doing so avoids interference to nearby stations. This is why dipoles, verticals and omni-directional antennas of all sorts are not very popular on meteor scatter.

The minute is divided into four quadrants of 15 seconds each. From the start of the minute these are 00 to 15 seconds (first), 15 to 30 (second), 30 to 45 (first again) and 45 to 60 seconds (second again). Then the next minute starts. So, you alternate between transmitting and receiving segments. If I was beaming East or South I would listen 00 to 15 and again 30 to 45 seconds, and transmit 15 to 30 and 45 to 60.
Note the "Tx even/1st" box ticked - I must have been beaming West
The reason for this arrangement is simple. It means that any stations in your area who are beaming in the same direction as you will all be listening at the same time. Otherwise, if stations transmitted during random segments you could find a local station transmitting while you were trying to listen.As the signal fills your receiver passband that would bring everything to a halt.

This system is not perfect. For example, at what point does "East and South" become "West and North"? Things get a bit blurred round the edges but in general it all works well. It would be impossible to use meteor scatter if everyone just transmitted at will. We will see the consequences of all this later.

It seems simple to transmit in the right segment relating to your beam direction, but it is very easy to get it wrong as I know only too well.

3) Don't waste time calling on the wrong segment
Not only will you annoy everybody around you if you call on the wrong segment, it does not really work either.

This is very easy to do by mistake. Whilst you may have ticked the box correctly, WSJT-X invites you to be quick and double click on the other station's callsign to enter their details and reply. Doing this will also set your tx period to the opposite of the station calling, which could well be the "wrong" one for you. I have been guilty of this by mistake.

Just clicking the callsigns and replying indiscriminately will get you into hot water with other local operators. Random calling works on Es with FT8 and JT65, but not on meteor scatter - regardless of mode.

4) Keep your PC clock accurate
Obviously this whole system falls down if stations fail to keep their station clock accurate. There are two commonly used systems for PCs, Dimension4 and Meinberg. No doubt similar software is available for Macs and other operating systems.

As a default Windows only checks the time when it is started up. This is not frequent enough as computer clocks are not very accurate and the errors over a long operating session would be too great for our purposes. There are various arguments for and against either Dimension4 and Meinberg. But still, either of them is vastly better than no clock synchronisation at all.
Meinberg working away - these are supposedly UK time sites but they are anything but.
 If your clock goes out of synchronisation you will probably drift gently out of the correct segment. This is not good because if you are trying to work someone part of your signal will be impossible for them to hear as they will be transmitting then. Also, this misplaced snatch will turn up in the receivers of those stations around you who are straining to hear weak signals. Not good.

5) Get on the right frequency
Just because your VFO says that you are on, say, 50.280, that does not mean that it is accurate.

Both WSJT-X and MSHV software suites provide variable settings for "FTol", or frequency tolerance. If your frequency is not accurate you have to hope that the other station (1) is on the correct frequency, and (2) has their FTol setting wide enough to decode you. Better still, get on the right frequency yourself, reducing the risk of falling outside the other station's FTol range.

The reason why FTol is variable is to allow for different computers in use by each station. The advice is to run the widest FTol which you can. Widening FTol increases the demands placed on your computer's processor.  WSJT-X comes with MSK144 set for narrow FTol (+- 20Hz) and the notes advise operators to increase this as far as possible providing their computer processor has the capacity to cope. You cannot rely on the abilities of the computer at the other end so get on the right frequency to start with.

If your rig does not have one, add a higher stability TCXO oscillator. To find out if you need one, a simple thing you can do is to look at the frequency recorded by the software from received stations. Good local stations should be a guide. Doppler shift tends to vary the dx stations by 10 or 20Hz each time, but it is still interesting to see if you are roughly right ...
OH7TE is close to 1500 so he might decode me if he could hear me (he couldn't hear me anyway)
 If most of the frequencies you see are spread evenly on either side of 1500 you can be pretty sure that you are more or less right. If all of them are above, or all of them below, or the differences are more than about 50Hz in many cases, it might be worth calibrating your frequency.

The other (not recommended) way to find out that your frequency is not accurate is to go on anyway and find that nobody is replying to your CQs.

6) Get off the right frequency
That sounds odd given the last suggestion (5). This time I am assuming that your VFO is correctly calibrated and stable, but the frequencies you want to use are very busy.

It is best to get off the "centres of activity" frequencies as soon as possible. You can do this easily by using that frequency as a "calling frequency". The standard approach is to call CQ and give the working frequency you want to use in kHz. For example here I am calling on 70.170 and listening on 70.712.
In WSJT-X, the rig VFO is set to 70.172, the TX CQ to 170 and settings to "Fake it"
In the example above the message sent is "CQ 172 GM4FVM IO85" and WSJT-X changes the VFO on every over to send that message on 70.170 but revert to 70.172 for reception. So if any station wants to call me they only have to turn their VFO to 70.172 and carry out a normal QSO. As soon as I hear a call on 70.172 I uncheck the box beside "Tx CQ 170" and a normal simplex QSO results. This keeps 70.170 clear of long drawn out QSOs.

MSHV does it differently, using the split VFO arrangement in most rigs, but the effect is the same in terms of the message and the outcome.

The frequencies in common use for MSK144, as far as I can see, are 50.280, 70.280 and 144.370. I cannot comment on the "rightness" of these centres of activity. I know that 50.280, for example, is not in accordance with the Region 1 band plan. I am just reporting on what I see.

People seem to be more likely to use a different working frequency if there is a lot of activity, and it is more common on 2 metres where contacts often take longer.

70.170 is an interesting case. During the periods when German stations have access to the 70MHz band it becomes a sort of multi-purpose calling frequency. I have heard CW, SSB, JT65 and FT8 on it. However, when there is no Es or tropo propagation it becomes a sort of meteor scatter calling (and working) frequency.

7) Consider the Hot Bearing
No, not your big ends knocking, Hot Bearings in this case are alternative beam headings. Strictly speaking the direct beam heading between your station and a dx one will not work well for meteor scatter due to the scattering pattern. The ideal heading varies during the day and with the distance between the two stations.

Luckily both WSJT-X and MSHV calculate the "Hot" angle once you enter the locator square of the other station. This can be either a "Hot A" or "Hot B" angle, but the distinction does not matter for our current purpose.
MSHV suggesting a Hot A bearing of 134 rather than the direct angle of 118 degrees
It is worth considering the Hot angle and trying it. Personally I follow the advice given to me by Bryn, G4DEZ (SK), who suggested aiming "somewhere in between" direct angle and Hot Bearing. In my case, with modest gain antennas, the beamwidth is not narrow anyway and my telescopic tube masts introduce some slack, so my antenna angles are not very precise.

WSJT-X marks these Hot Angles simply as A and B and there is little in the guide to explain what they mean. I suspect that not knowing about the Hot Angles is the cause of many missed contacts.

8) Don't assume that MSK144 only works during the mornings of meteor showers.
As I write this the Perseids shower is due to peak in three days time. Already the bands are busy. The Perseids is a long lasting shower so it is not sensible to limit yourself to the peak couple of days.

These showers can be great fun but meteor scatter propagation is possible every day of the year. It is also possible at any time of the day. It is just that sometimes it gets harder. We like harder. Harder is character forming. Easy is fun but you don't learn much.

The major showers are listed on sites like this:-

Whilst the average shooting star observer needs to pick a shower period listed on these sites to see anything interesting, we in the radio world can find meteor trails at any time of the year (and in daylight too!).

Associations like the RSGB and ARRL list major showers in their propagation predictions.

Be aware that the Southern Hemisphere is affected by different shower patterns. If you happen to live in the Southern Hemisphere expect everybody to just assume that you live in the Northern Hemisphere. It is like your national radio society assuming that you live within 25 miles of their office. It comes with the territory of living where nobody expects you to. An unusual place like "Somewhere in the World". Golly gosh.

Anyway, 06:00 outside a shower period is likely to be as productive as 18:00 during a shower. And 18:00 at any time is better than not getting on the bands at all.

9) Use the most up to date software.
For some reason I cannot understand, several 2m meteor scatter operators still use the technically inferior FSK441 modes. Personally, I prefer a mode that works better, and MSK144 is that mode.

MSK144 uses 15 second transmit periods, which is remarkable to see in operation during a strong meteor shower. QSOs are over in a minute. Also, there is none of the panic with FT8 over getting the right macro running at the start of the over - you can change the macro at will during a segment. So if you are sending CQ on  MSK144 and you see that someone has called you, you just change your tx message mid-transmission and if the conditions permit it will be decoded at the other end.

I have an old copy of "the Amateur Radio Operating Manual", dating from 1991. The meteor scatter procedures in there are mind boggling. They are complex way beyond the rather fiddly methods described above. We do not know how lucky we are. I had forgotten most of it, and luckily now you can forget all of it.

10) Try the different bands
The days when "VHF" was simply assumed to mean 2 metres have gone. 4m if you have it is great for meteor scatter. 6m is good too. The bands have different feels to them. On 2m the pings are shorter and a lot of QSOs are pre-arranged. On 4m and 6m the signals tend to last longer and everything is much more relaxed.

11) Have fun
You don't need a kilowatt linear. You don't need a big antenna. If you already have a beam and WSJT-X you already have the setup. If you can do JT65 or PSK you can do MSK144.

Even if you just turn on and start you are not likely to fail completely. Keeping to the suggestions above will improve your strike rate. But if all you do is tune in and listen I bet you will find it fascinating.

See you during the Perseids.




Thursday, 27 July 2017

More on FT8, WSJT-X1.8.0-rc1 and imaginary band conditions

Well, I have had a lot more chance to work with FT8.

1) When FT8 does work

Included in my activity has been more time on 40m which was good fun as it included a QSO into VK and then I missed this ZP9 because I had to go out and quell a cat fight in the garden (don't ask, it involves a "Squeezy" bottle full of water - not to wet the cat but to cause it to find a close shave enough to leave the premises). ZP9 on 40 would have been a new one...

ZP9CTS missed on 40m at GM4FVM on 23 July 2017
Still, VK will do nicely.

In operation it is fairly easy to cut out an entire 30 seconds of otherwise missed DX opportunity by being quick to reply to calls.

I leave the PC pointer over the second line above the bottom (once the "Rx Frequency" box has filled - before then you have to pick the lowest blank line). It takes a bit of care to put it over where the other station's callsign will appear. Then I resist the temptation to click as soon as their callsign is decoded (on the line below). This is because my reaction time is not quick enough to click on that before the callsign moves to the line above.

 It certainly works if you click it within 2 or 3 seconds. Here is what the result looks like, showing that the next CQ was interrupted by the reply within two seconds and the other station received it fine ...

I have decided not to get steamed up about the superfluous 73 which often happens. Yes, I could hang over the spot with my pointer ready to click if I failed to get a 73. This might save 30 seconds. So far I cannot see the need to do it. It is worth doing it when getting replies to CQ calls as otherwise people can get fed up and stop calling.

2) When FT8 does not work

I have had a series of mysterious failed contacts where my reply was not decoded at the other end even though we were strong signals in both directions.
LA7DFA not decoding me on 6m for 20 minutes. Click to enlarge if necessary.
I was calling LA7DFA all this time and he only copied me once. After I got his report I sent mine but he did not decode that at all. This went on for twenty minutes. You can see that I missed his messages quite a few times too, even though I could see a big signal on the waterfall. Signals were strong enough and Per sent me several emails about it as things went on. There was little that we could do about it. Eventually Per suggested that we move to meteor scatter and once we had sorted out an "FTol" settings issue with MSK144, the QSO was instant. Hardly surprising as I could hear Per clearly.

This failure and a few others like it are rather mysterious. It does not seem to be a timing issue and I have switched back and forth between Meinberg and Dimension 4 several times which makes no difference. Signal strength is not an issue. Usually the other station has decoded my CQ and perhaps my reply. Drift does not seem to be involved. Sometimes I have decoded their message once, but not again. Sometimes it passes, other times it goes on for ages (though the example above is extreme).

A bit of a mystery that situation. I see others seem to be affected too. I still feel that I must be doing something wrong.

3. When nothing works (or so I imagine)

Between 1 July and 27 July 2017 I worked only 4 stations outside the UK on the 70MHz band.

This seemed so bad I decided to compare it with 2016, when the figure for the same period was 5.

Then I checked 2015, and then it was 7.

So four is not so bad. I do not recall July being quite so bad on 4m.

On 6m, by comparison, in 2016 I worked 18 stations and in 2017 I worked 55. So July is not so bad on 6m, and certainly not when I can rattle through the contacts on FT8.

Ah, the good old days. When July was full of 4m DX and the world was well ordered.

What went wrong?



Wednesday, 19 July 2017

WSJT-X and FT8 - you have to be quick

This is not a criticism. I like FT8. This is just what I found by trying to use it on the busy bands.

After a night using FT8 on 40 metres, I have to say that it is very efficient. It proves, however, that I am not as efficient as I might like to be.

It all comes down to managing the 15 second time segments.

In a nutshell, the transmitted signals have to start right at the beginning of the tx segment (of course), but this is very difficult to achieve if you are waiting to see a decoded signal from the other end. So human intervention, which may not be well timed, was tending to slow everything down.

Lets us suppose that I decide to call CQ, just like the 40m calls last night.

EDIT I have corrected typos in the timing, but the point remains the same.

I might do this during segment 1, at 0 minutes and 15 seconds.

1. 0m 15s CQ GM4FVM

Unless I was fairly careful or had set this on the earlier receiving segment, it is very unlikely to start at exactly the right point. Much more likely it will start after the beginning of the segment and therefore not be a signal which can be decoded by anyone else. Thus the next segment, my receive one, will be silent.

1. 0m 15s CQ GM4FVM
2. 0m 30s Silence

Set up as it is to auto repeat, it will call CQ again next time.

1. 0m 15s CQ GM4FVM
2. 0m 30s Silence
3. 0m 45s CQ GM4FVM

Anyone likely to reply to me will have to wait to see the decode of my signal (duh!). From what I have seen, not many people with normal reactions can click on my callsign in their software before the next tx segment has begun. With only 2 seconds available for decode, reaction and processing that is hardly surprising. The rapidly ageing demographic of amateurs (including me) only makes this less likely to happen.

So at some point during the next segment I get to see a reply, but it is never going to decode.

1. 0m 15s CQ GM4FVM
2. 0m 30s Silence
3. 0m 45s CQ GM4FVM
4. 1m 00s Trace seen but no decode

There is no time for me to put up "QRZ?" either, as I have to wait to see whether that trace decoded or not. So I just send CQ again. There is nothing for the other station to do either, other than transmit again, but this time I will decode it as it started automatically at the correct time. It turns out that it is A1DX, a (non-existent but) very desirable station to work.

1. 0m 15s CQ GM4FVM
2. 0m 30s Silence
3. 0m 45s CQ GM4FVM
4. 1m 00s Trace seen but no decode of call from A1DX
5. 1m 15s CQ GM4FVM
6. 1m 30s GM4FVM A1DX KM33

Great, A1DX, a rare station in a fairly unusual square! I have to wait to see the decode, by which time even though I click on A1DX's callsign it is too late to get the full message transmitted and she only gets two fragments which she cannot decode. However, it shows at my end as having gone (along with the record of another CQ which it interrupted, showing up as two tx lines on the panel).

1. 0m 15s CQ GM4FVM
2. 0m 30s Silence
3. 0m 45s CQ GM4FVM
4. 1m 00s Trace seen but no decode of call from A1DX
5. 1m 15s CQ GM4FVM
6. 1m 30s GM4FVM A1DX KM33
7. 1m 45s CQ GM4FVM/A1DX GM4FVM +03

At this stage A1DX will see that I have replied but get no decode, so she just sends her call again. We all need to be patient here.

1. 0m 15s CQ GM4FVM
2. 0m 30s Silence
3. 0m 45s CQ GM4FVM
4. 1m 00s Trace seen but no decode of call from A1DX
5. 1m 15s CQ GM4FVM
6. 1m 30s GM4FVM A1DX KM33
7. 1m 45s CQ GM4FVM/A1DX GM4FVM +03
8. 2m 00s GM4FVM A1DX KM33

At this point automation takes over and the rest of the QSO proceeds very quickly without further intervention by either of us (just as well given the speed of our reactions). The path shown next will be followed providing that A1DX has the "Auto Seq" box ticked, but it turns out that she has. Otherwise it will take forever to do this.

1. 0m 15s CQ GM4FVM
2. 0m 30s Silence
3. 0m 45s CQ GM4FVM
4. 1m 00s Trace seen but no decode of call from A1DX
5. 1m 15s CQ GM4FVM
6. 1m 30s GM4FVM A1DX KM33
7. 1m 45s CQ GM4FVM/A1DX GM4FVM +03
8. 2m 00s GM4FVM A1DX KM33
9. 2m 15s A1DX GM4FVM +03
10. 2m 30s GM4FVM A1DX R-16
11. 2m 45s A1DX GM4FVM RRR
12. 3m 00s GM4FVM A1DX 73

OK she might send 88s, as we do go back a long way.

But anyway, now a further issue arises. If I have by now altered my WSJT-X panel to send the next CQ, I will not know if A1DX sent 73 until it is decoded. She might have not received my RRR and then she would send R-16 again, which would mean me changing everything again and wasting time. So I am almost obliged to leave everything in auto until I see the decode of 73, by which time it is too late to stop me sending 73 myself. If I do intervene by changing this to CQ it gets me nowhere because the resultant changed message is not able to be decoded by anyone. So I end up with this ...

1. 0m 15s CQ GM4FVM
2. 0m 30s Silence
3. 0m 45s CQ GM4FVM
4. 1m 00s Trace seen but no decode of call from A1DX
5. 1m 15s CQ GM4FVM
6. 1m 30s GM4FVM A1DX KM33
7. 1m 45s CQ GM4FVM/A1DX GM4FVM +03
8. 2m 00s GM4FVM A1DX KM33
9. 2m15s A1DX GM4FVM +03
10. 2m 30s GM4FVM A1DX R-16
11. 2m 45s A1DX GM4FVM RRR
12. 3m 00s GM4FVM A1DX 73
13. 3m 15s A1DX GM4FVM 73
14. 3m 30s Silence
15. 3m 45s CQ GM4FVM

Thus, in theory a 6 segment cycle (as it often is on JT65) becomes a 14 segment cycle. The FT8 segments are only a quarter of the length of the JT65 ones of course.

If it goes round again, the correct start time of segment 15 reduces subsequent iterations to 13 segments. Instead of calling CQ after 6 cycles on JT65, I ended up calling CQ after 12 cycles on FT8. This produces twice as many QSOs on FT8 compared with the same time on JT65, not four times as I might have expected before actually trying it.

It is quicker if you are the one answering the CQ of course. It takes longer if you are the one calling CQ as you have the dead rx periods.

I recognise that there might be some failings on my part due to my slow reaction times. The other stations seemed to be doing the same. I tried to sharpen up at my end, for instance by being ready to double click on the other station's callsign as soon as it appeared on my panel (you have to do it on the "RxFrequency" side as it moves up the screen on the other side, plus it will move up a line as soon as you start to tx, so I aimed for the second line up). This usually saved two segments, but I had to be lightening quick.

Nobody at the other end seemed to be moving any more quickly than I was, and all the QSOs were like the one above. I had to call CQ twice before I got a decode of the other end's callsign, even though after the first CQ I could see something on the waterfall. It was never decoded the first time. They were not getting as quick as I was.

With careful timing it is possible to reduce this process, but nobody was doing it last night. My lack of ability to avoid sending a second redundant 73 at the end of the cycle really annoyed me, but I just did not have the time to get it right and change over to CQ as soon as I had received 73. That is my standard procedure on JT65. Maybe I just need to loosen up and accept that as the whole process is better then the odd missed segment is OK.

This all seems simpler on MSK144. The modes are not technically comparable, but MSK144 also has 15 second segments. There is enough time to work out what to do next on MSK because timing is not important on meteor scatter - and on 60 second JT65 there is plenty of time even though you still need to concentrate. I pondered a bit on whether the same FT8 protocol with 30 second segments (with the extra 15 seconds devoted simply to deciding what to do next) would actually take the same time to complete a QSO. The answer with some of the real-life contacts was "yes".

Of course the built-in automation takes a lot of the problems out of all this. It works 100% fine. It is only when cranky old humans get involved that it all goes awry. Well not "awry" as it still works, but it diverges from the ideal. Put simply, my desire to complete "a QSO", meaning all the stuff done right, is part of the delay. I am the one deciding not to go straight on to CQ without seeing 73, but then that seems pretty logical to me. Let me put it this way - I do it on all the other modes.

Further automation, like automatically replying to the next signal or the weakest signal, is on the way for FT8. The snag with this, despite the attraction for others, is that I don't want to do it. I really want to know who I am replying to to before I reply. The UK does not have a "banned list" but some DXCCs do. In general I just do not want to be able to work everyone who might just call me.

Automatically going to CQ once 73 is received would be a good option for me though.

This is a fine balance to strike. At what point does speeding up the QSO get too fast for the operator to keep up with?

In the early 1980s I was taking a post graduate course at Queen's University of Belfast. I took an option in Ergonomics, which examined what was then called "man/machine interface". You know, aircraft cockpit dials all reading the same way, and how to design a control panel for a nuclear reactor. Great stuff and very useful in later life. Well ...

At one point we were trooped (!) into the university "Drill Hall" where a line of personal computers was arranged. I had never used a personal computer before, as the only computers I had used were the size of small buildings. We had to compare the interfaces on Microsoft and Macintosh machines. Microsoft was DOS, the Macs had ... windows. I wrote a long essay (my essays are still long) to say that windows were a much more accessible human/machine interface than obscure keystrokes. Speeding up the process using windows still left the operator with enough time to decide what to do next at their own pace, having been provided with timely visual clues. Did Microsoft read that? I don't know, but that is my qualification to blether on this topic now. I studied ergonomics you know.

I might have just got a bad night on 40m, with everybody new to the mode. However, it looked a bit like we might have got near to the limit as to how far we can shorten the reaction time available to operators and still expect them to sort things out in time. We can react more easily to messages that can be decoded as they arrive - like CW - where the message is gradually building up during the QSO. With data modes however, you get nothing until you are presented with a fully decoded message or still just nothing. What you do then is limited in all sort of ways. Further automation is possible but do we really want it?

Here is an FT8 QSO today on 6m ...
50MHz FT8 at GM4FVM on 19 July 2017. Click image to enlarge if necessary
This is better than the 40m ones last night. There is the same jittery start. Did he not hear me the first times I called, or did he click to reply during a segment and I did not decode the partial message? There was QSB. Once we got into automatic mode everything went well until two 73s and even an extra one from me which I cancelled part way through. It is not really comparable with last night, as on 6m DX everybody is keyed up and concentrating, while on 40m around Europe it is ... different.

Let us get this straight. Most of the QSOs I had would never have taken place on JT65, and no other mode either. Whilst FT8 might not be working for me at four times the speed of JT65, it is certainly getting through the QSOs at twice the rate, which means half of the 40m ones would never have happened in any other mode. As for the 6m contact, well -17dB is a pretty weak signal, so FT8 won the day technically. Once he actually heard me and started his reply the QSO was complete in another 45 seconds. With JT65 the QSB would have got him before the end anyway. I am a fan of FT8.

FT8 works. The high pace makes me feel fraught and unlike JT65 there is not much time for logging and feeding the cat between overs. I can cope with that (can Katy?). However, it is a bit ... wearing ... keeping up with it. Worth the effort though.

The protocol works very well, the operator is in need of a software upgrade.

If you ever need your nuclear reactor control suite updated, you know the person to call. I will put in some delay time to allow for second thoughts before pressing "go" - you cannot get people to react fast enough and still see the consequences of their actions. Other people! Eh? Who needs them?

I wonder did windows ever catch on in computing?




Friday, 14 July 2017

VHF data frequencies plus WSJT-X 1.8.0-rc1

Thanks to David, GM4JJJ, for pointing out me that the long awaited sharpening of the blades of WSJT-X, version v1.8.0-rc1 r7847, is now available at the WSJT Home Page link on the right. Follow the link  to WSJT-X and select the "candidate release" of WSJT-X 1.8.0.

Our attention was immediately drawn to a new "mode" (or protocol as some people put it). FT8 offers many advantages over JT65 on VHF. In particular it should suit weak long distance signals affected by QSB and Doppler.

At first glance there are several features in FT8 which I can certainly see will help. Immediately noticeable is a 15 second segment time which is just what we need for DX. This means that a QSO can be completed in a minute. If you want to know why that is important ask a CW operator. On JT65, a mode otherwise well suited to VHF DX work, you can sit and hear a station for a minute, reply, and at the end of 2 minutes get nothing back, never knowing whether you were heard or not.

I used to work with a guy who said "try to see the bigger picture - what does this mean for me?". Tee hee. The bigger picture here is that I might have worked Japan in the time I sat and watched many JA stations calling CQ. Quite possibly they were also watching me and other Europeans calling CQ, and the path just was not open for two minutes. Yes, overall it was open for a hour or more, but between any two stations it was only open for a minute or two.

I can get a whole QSO done on FT8 in a minute ....
A full QSO on FT8 in one minute, with 15 seconds thrown in for the 73s
At this speed you have barely enough time to respond so there is auto sequencing to reply automatically. Anyone who has used 30 second segments on MSK144 will feel very comfortable with FT8.

Not only are the segments shorter, but the synchronisation is at the start, middle and end. A readable signal in a 15 second segment should be 100% decoded, whereas the same length of strong signal would be less likely to decode in a 1 minute JT65 segment and even less so in 2 minute WSPR one, depending on the fading. If I understand it correctly, the chance of decoding is better as the segment gets shorter, thanks too to more frequent synchronisation. That is another plus for FT8 but not at the level of the "fast" JT modes like MSK144 or fast JT9, which can decode tiny fragments of signal. However, it does represent a huge step forward for the terribly weak and fading VHF stations we now hear.

What FT8 seems to represent is a very clever blend of tweaking the protocol with tailoring to the WSJT-X wrapper. So while a better decoding process will bring benefits (-20dB is promised), cutting the segment time and auto sequencing will bring much more chance of working those fleeting Japanese, Chinese and ... well, who knows where? ... stations.

I tested it by working a few stations and some I could not decode due to their clearly late timing. Every well timed station was copied easily.

Apparently it is possible to set it to automatically reply to the first station which comes back to your CQ, and further developments will see it able to reply, not to the first reply, but the weakest reply out of several. Now that is a DX-ers dream.

I worked a couple of stations using FT8 on what I am pretty sure was iono-scatter. It was neither as steady nor as strong as Es, and it certainly looked like that mode. FT8 looks like a great mode for iono-scatter, and once Es has faded it will be very interesting to see how we get on with the even more esoteric propagation methods. I will be particularly interested to try mixed iono/tropo/meteor scatter - type melanges.

EDIT - by melange I mean mixture - not the drug in the film, which was fictional by the way. Nor the "Melange" two stroke oil/petrol mixture machine I used for my Puch motorbike in the 1970s.

MSK144 seems to have totally replaced JT6 on 4m and 6m meteor scatter. I would really like to see FT8 replace JT65 on VHF Es. What chance of that happening? Not much I suspect. Human nature being what it is (the rest of this has been deleted so as not to offend the dozy old duffers in the hobby who think we should be running a museum).
I am not even going to start on the great 6m "operators versus the band planners" debate. What frequency should we use - the one the Region 1 band planners think we should use, or the one that works?

I did raise this before, and I will explain it at some stage for anyone who is understandably confused. But for now, I just do not want to get involved.

I was involved at some stage in the past with the 4m equivalent. I had some discussions with the then RSGB VHF Manager. It was easy to agree with this gentleman that 70.091 was good frequency for WSPR on 4m. Much later a row developed between me and some others versus a self-appointed rule maker about this. We won the argument as 70.091 remained, but I was hurt, bruised and annoyed by the whole episode - enough to put me off 4m WSPR for years.

Lately, several of us have been putting forward 70.176 for JT65. This seems to have stuck. I have worked a number of DXCC on that frequency and I see others doing it too. I have no particular qualification to decide these things, just 40 years of using the band and an interest in using data. That self-appointed rule maker seemed to be more interested in STOPPING me using data.

Thank you to several VHF supporters for occupying 70.176 and making it unofficially ours.

So with the arrival of FT8 a pattern of allocations emerges which would put, in ascending order, FT8 on 70.174, JT65 on 70.176 and by analogy, JT9 on 70.178. MSK144 is already on 70.280. WSPR is already on 70.091.

None of these frequencies is "right". The contesters will complain about infiltrating their precious bands, but then data modes are in use during openings, whereas contests never happen during openings (erm, or so it seems). I do not want to start a whole debate about 70.176 as it is now in use. The other modes as suggested by me fit around this as they do on other bands - leaving the 6m shambles out of it for the moment. So does anyone object?

Total data users on 4m - about 20 maybe. Total bandwidth used = very little, during periods of vanishing brevity. Surely this is not too much to ask? Just somewhere to go to find similar minded folk. A sort of "data cottage" - no maybe we should not suggest data cottaging on a family-oriented blog. A data village pump. That is a better idea. A centre of activity. And anyone who wants to transmit any other mode over it can do so. After all, it is in the "all modes" region.

Actually, it doesn't matter all that much. I have discovered that 4m operators can actually turn their VFOs and find other people. There you are, on 5MHz they transmit outside the band because they do not have the wit to change frequency, but on VHF we can actually listen in different places at different times. Amazing. Chapeau. Speaking of which, isn't Fabio Aru amazing?

This area around 70.176 is pretty good for the various international frequency allocations we have at the moment. It is not perfect, but it might be OK. There might be an argument for moving WSPR to 70.172 to fit in, as 70.091 is not so widely available, but I do not want to start that row up again.

Well, I have said it now. I bet there is an argument about this idea.




Sunday, 9 July 2017

Amateur radio rotator rant

OK, I have been fed up about this for ages and it is time for a full-frontal whinge.

There certainly is a thing called "buyer's regret". That happens when you buy something and then wish you had bought something else. This is not the case here, I think.

I think that none of the rotators on the market meets my needs, for reasons I will explain.

The thing about rotators is that the market for them is not very big. In my career I have had three rotators, the first two bought second hand. So in my first 40 years of radio I spent less than £100 on the first two. Then I gave the first one away about 10 years ago (a Ham M dating from the 1960s). It went to a needy new amateur. The second one, a Yaesu G-600, which must be 20 years old now, is still in use.

Then eventually I had need of another one (maybe I should not have given away the HamM). I bought the third one for (I cannot recall how much now) but it would now cost £376.75 for the rotator, plugs and bottom clamp.

£376.75 for the most basic rotator on the market (the Yaesu FT-450)!!!

That does not include postage or the cables. Nobody is likely to use less than 30m of cable. 40m supplied by Yaesu and complete with the plugs costs £100. You can do it for less, but with the plugs costing almost £30, not much. You can find the plugs on eBay for a few £££ and get your soldering iron going. As for the cable, at one point in one of my runs the rotator cables is two parallel runs of old mains flex (total cost for that bit £0).

If you buy the long cable and the bottom clamp that brings it to £480.

You can, for sure, do these things to get the price down. Once you do so, you are departing from the CE approval which is needed to sell appliances in the EU. This is meant to protect you. If you do something like use old mains flex and then your house burns down, your insurer may take a dim view of you departing from the CE marked "official" Yaesu cable with its pre-fitted plugs.

I looked fairly carefully at the small rotator market at the time. The Yaesu was not my immediate choice. I would have preferred a worm-drive mechanism, which the SPID rotator has, but even the lightest SPID appears to be much heavier than the Yaesu and claims only to take 50mm diameter masts (mine are 52mm).

Also on the market seem to be:-

The equivalent Hy-Gain rotator, the venerable AR-40X sells for £449.95.

You could get a Create RC5-1 for about £500 (+ £££ bottom clamp) or the Spid RAU is £480.

Now if you take a step above the entry level there is much more choice. However, these are choices not available to me. My mast is light weight and not able to accept anything much heavier. Anyway, if you pay enough for a rotator you can get anything you want, which is not the point for anyone on a budget. It is a bit like me remarking on my £1000 rigs and then getting emails from people saying that a £4000 Elecraft radio and matching Elecraft linear is better. Yeah, sure, and a new Rolls Royce would be better than my 8 year old Volkswagen. I keep making points like this but the Elecraft "my wallet is bigger than yours" brigade keep writing to rub my nose in the dirt of my limited budget.

My gripe is not so much that the Yaesu rotator I settled for is not really very good. Well, it is not very good at all really, but then for a motor, some gears and a housing, what do I expect?

My gripe is that at least some of the cost of the Yaesu, (and the Hy-Gain and Create) rotator must go on providing me with the mechanical indicator. When you think about it, this is a masterpiece of electro-mechanical engineering. However, I don't need it, I don't want it, and I cannot see why they persist on selling it.
Controller for my Yaesu G-450 complete with clock-face indicator and no digital control
Going back to my old Ham M, it had a nice simple single slider control on the front. Sprung to centre off, and a slight pressure either side released the electro-mechanical lock on the rotator. Any further pressure on the slider moved the antenna. You could stop turning it and keep the slight pressure on so that it coasted to a halt before allowing the lock to engage. And the display was a simple meter calibrated from South to South via North - it just read the voltage coming down from the resistor in the rotator.

Then moving on to the Yaesu 600, its control box had two buttons, left and right, plus some dorky wiring to stop you trying to turn the antenna both directions at once. It also has a lock, but you cannot control it separately. And it had this amazing clock-face 360 degree indicator, which the Create and the Hi-Gain have too. This a great thing, but does it really tell me much more than the old meter did? They used to sell the meter version alongside the clock-face ones, and the meter version was cheaper (of course). Now you have to shell out on the fancy display.

None of this would matter had my display on the G-600 not failed. Maybe after 20 years that is not so surprising. But whilst a meter could have been fixed, this marvel of all that clockwork complexity was beyond me. So I bought an EA4TX digital control box, reviewed here. Now this is a great device but it costs almost as much as the Yaesu G-450, once you have added the tax and carriage, and you have a lot of tinkering to get it to work. It was a simple choice when I was faced with the G-600's indicator failure to buy one, and it has kept that rotator in business for another couple of years, but it is a lot of money and work to go to if I want to replace my G-450 indicator.

Let us just consider this. I have one rotator under computer control, the G-600. I had to re-wire the G-600 controller to extract the motor voltage and organise the new EA4TX box. It worked out fine in the end. Now I would like to have the G-450 under computer control and the sums just do not add up. I need to delve into a perfectly good controller to get the motor supply out, and then spend as much as the original rotator on a control box. Crazy.

So why don't Yaesu just sell a controller with two switches and digital readout showing azimuth? Or even a small LCD screen with a pointer on it? And, crucially, a nice USB socket allowing connection to a computer? After all, this is what SPID do for the RAU. And high end, larger, heavier, more expensive rotators do allow easy hooking up to a PC.

I think that the problem for Yaesu and the other manufacturers (except SPID!) must be that any investment in updating the rotator control box must be a very doubtful proposition when they only sell most amateurs one or two rotators in their entire career (in my case, one every 20 years). You need to sell a lot to recoup the cost of re-tooling your production.

Set against that, most electronic devices now have been redesigned in this way. Moving parts are minimised. Even a single humble meter can be the cause of a re-design, to be replaced with a digital readout. Transverters have been redesigned to replace a meter with a numerical display or an LED strip display, and transverters are very low volume products. So surely the cost of making those mechanical clock-face displays must justify a change of direction (ahem!).
The EA4TX shows how simple it is to include PC connectivity and stand-alone back up.
From what I can see SPID do a display with a simple three figure azimuth read-out in degrees. This has a USB output for the PC. You can use this "stand alone" without a computer using the display, or with the computer using the USB socket.

You can add on interfaces for some Yaesu rotators but you have to buy the unwanted display first and the interfaces are expensive and do not work with the G-450 anyway.

What I would really like to see would be Yaesu making a modern controller for the G-450 (and I suspect the G-650) with a built-in power supply and a socket for their standard rotator plug. This would be a straight replacement for the existing rotator control and it would feature a USB socket. As well as being available with the new rotator (and surely cheaper than the exiting controller) it would also be sold as a replacement for people like me ... or those whose mechanical readout has inevitably failed.

But, you say, there already is such a device. Yes, believe it or not, Hy-Gain sell just such a thing for Yaesu rotators - the YRC-3X. Weird. They sell a device to fix their competitor's rotators. This is exactly what I want. Downside? It costs £449.95, just for the controller. In other words, I could just about buy a brand new SPID and its perfectly suitable controller, for the price of the Hy-Gain replacement box.

If only I knew for sure if the SPID does fit my masts or not. 50mm - do they mean that as an exact measurement? And as for the weight quoted for the SPID, are those shipping weights for the whole kit, or just the weight of the rotator? I am fairly sceptical about the level of detail you get for these things, after all, the torque and wind loading figures given are not comparable between makers either.

You can see that if I could sort out the details I would rather sell the Yaesu G-450 and buy the SPID than spend the same amount of money buying the Hy-Gain box to convert the Yaesu. Not that there is anything wrong with the G-450, just that I am irritated by paying twice to get it working the way a  modern rotator should.

Anyway, Yaesu continue to sell an outmoded and no doubt expensive to make controller and give no option for purchasers but to buy it. I bought one. The rotator is OK, as far as cheap rotators go. It meets my needs in the sense that it has not broken down yet - though the first Yaesu G-450 which was supplied to me was seized solid and it took weeks to get a replacement. If the wind causes the gears to strip then I will know that it is not good enough mechanically. I already know that it is not good enough when it comes to the controller.

I suppose that the manufacturers are stuck with small volumes of sales. If Yaesu think that selling the G-450 with no computer connectivity will force people to buy heavier and more expensive rotators then they are wrong, as they would be too heavy for me. I cannot blame Hy-Gain charging a high sum for their replacement Yaesu controller as the market must be small. So, come on Yaesu, get that controller modernised and start selling replacements.

Where is the Chinese manufacturing industry when you need them? A rotator is a 30volt-ish motor, a bearing or two, a couple of gears and some castings. A controller is two switches, a display, a circuit board with a couple of relays, PSU and USB socket. Surely that could be done for less than £380? In radio terms the volume may be small, but someone could corner the market with a well-priced rotator. If the existing manufacturers cannot modernise and innovate (with the exception of SPID who do try), then can newcomers come in and shake it all up?

Where is Adam Smith's hidden hand? (Note: obscure reference to the Father of Economics, who also resided in IO85 square).

Rant over.




Wednesday, 21 June 2017

Es and broadcast QRM, the Wouxun 950PL, and 2 computers with PstRotator

Sometimes with amateur radio you just have to wait and watch...
Katy, 2nd operator at GM4FVM waiting patiently
At other times you let your guard down. You go off duty, you get slack, you relax. You know, you have waited for ages and nothing showed up, so you took it that nothing was going to happen.
Katy has slackened off She is in there as her tail shows
It was when we were slacking, two days ago, that we missed Moldova on 2 metres. That would have been a new country and a new square. I saw something happening on EsSense, but I went out and cranked the antenna up and poured myself a Ribena, then I came into the shack and heard somebody else working Moldova and then the opening was over. Grrrr.

You win some, and you lose some.

Often, when Es is at its strongest, there is simply nothing to work. On 6m here the band is full of Russian (and general Eastern from here) TV signals. On 4m there are lots of OIRT broadcast signals. The noise gets so high that the rig overloads. Curtains. I might as well climb into Katy's bed (no tail to show, honestly; I am not The Devil).

Here is such a day (18 June). Although a bit short of overload, the radio was full of OIRT on 4m and no further progress could be made. I have got used to sitting this type of thing out. I might be able to hear an SSB signal in there, but there is no chance of being able to understand it. Not with my ears anyway.
You might be able to see, just between two peaks of FM broadcast, a faint line which is indeed an amateur signal. Right in the passband of the receiver on 70.176
That line is indeed DG0KW. I had just worked DF5VAE (accidentally I was on 70.170, but he still found me). Apparently JO64 is new square for me though I was surprised by that.

It certainly looks as if you can squeeze a JT65 signal between the sidebands of the FM broadcast signals. In fact, DF5VAE was more of less on top of an FM signal, yet he was easy to decode.

I am beginning to get the impression that JT65 works quite well in the face of heavy FM interference. I suppose CW might work too, but JT65 takes the agony out of listening to the terrible raspy noises. I could never have worked either of them on SSB, and indeed I would not even have tried.

Just a word of explanation about OIRT for those of you outside Europe. The Organisation Internationale de Radiodiffusion et de Télévision is (or was) a group set up after World War 2 to establish TV and FM broadcast radio standards in Europe. The FM radio band they proposed was around 70MHz (now 65.8 to 74MHz). Western European nations left OIRT in the 1950s once 88 to 108MHz became their preferred band and OIRT was left to cover Eastern Europe, or in reality the former USSR and its affiliates.

In the past radio amateurs had to deal with broadcast stations in the 70MHz band from many countries in Central Europe. Gradually former "Warsaw Pact" countries abandoned OIRT frequencies and opted to go with 88 to 108MHz.

As far as I know OIRT as an organisation no longer exists, but the term "OIRT" is used to describe stations still operating on those frequencies. Typically, I hear stations in Russia (especially Kaliningrad), Ukraine, and Belarus, but other countries further East still seem to be operating too.

I believe that most OIRT stations are now just duplicates of stations in the 88 to 108 MHz band. It must cost a lot to keep them running as they certainly must rack up quite an electricity bill.

Wide band FM at considerable power is just one of the snags to get over when trying to work Es on 4m. It just shows how good the propagation is on that band. They do not make it impossible to operate, you just have to find ways to work round the commerical stations, as we used to do on 160 and 80 metres in the good old days.

Imagine my puny JT65 signal successfully battling through that wall of RF.
To be frank, I never really expected the Wouxun KG-UV950PL to become my shack FM radio.

I had intended it to be a mobile radio and I still think it would be great for that. However, it never made it past the shack where it replaced two separate rigs.

There is a good review of it here ... if the link is broken it is this ...

In my experience so far this review says almost all you need.

The 950 is really is two radios in one box, and one of them only covers part of the range. This is odd and hard to get your head around. I have one set up to cover 50 and 70 MHz, and the other for 144 and 432 MHz. Strange. Luckily mine came with the programming cable thrown in so I can tame it that way. I would hate trying to set it up manually as it took about 10 days to figure out how it works. At least with all the memory frequencies in place I could adapt to it and learn as I went along.

I had looked at the 950 as a possibility before, but it seemed too expensive. Adding the programming cable tipped the balance.
My Wouxun KG-UV950PL - I separated the control head from the rig to install it
What can I add to the G3ZPF review? I have it mounted with the control unit in the shack shelving and the radio itself mounted at the other end of the shack - the control cable comes as standard. I took the strain off the mic cable by adding a right angle ethernet plug with a cable to an ethernet "back to back" socket. The mic plug is therefore not tugging on the rig socket when you transmit.

There may be two radios in the 950, but there is only one RF socket. I already had a Comet CF-530 duplexer doing the same job for my Wouxun handheld in the car, so I brought it in to allow me to split the 50 and 70MHz signals from the 144 and 432 MHz ones.

The review mentions the volume control issue at low volumes. This is a snag for me - I cannot get it low enough with the inboard speakers. Easy enough with outboard speakers. So I just set the speaker on the microphone as my main speaker. In a car this would not be an issue as low volumes are not needed.

It takes a bit of getting used to. I suppose that every new FM radio does. Now that I know that it takes two presses of the PTT coming off scan to work the transmit function, I can do that. I can now enter frequencies via the keypad, but the process takes some remembering. However, I use it almost entirely on memory mode.

Now that I have had it for a few weeks I can say that I thoroughly approve of the Wouxun 950. The basic 950P model covers 10, 6, 2 and 70cms, and that might be the one for you. However, the 6, 4, 2, 70cms "950PL" version is the right one for my particular purpose. Both versions are marked 950P on the front, incidentally.

Aside from the rather odd control arrangement, the radio side is fine. It is powerful (40 to 50W) and sensitive. The squelch works well. Sensitivity is similar to other single and dual bands rigs I have used, and there appears to be no performance penalty by reducing the rig count by one. It is certainly streets better than the ancient ex-commercial PMR radios still in use of 4m.

As well as looking as if the case is used as a heatsink (as on my previous VHF FM radios) the 950 is equipped with a cooling fan. This is great. I used to have radios like the Yaesu FT-1900 and 2900 which got incredibly hot. A cooling fan is very useful, and I cannot hear it.

At almost £300 it is a bit pricey for what me, but then it is better value than some other quad band rigs. Now that I have got used to the quirks, I like it.
I have gone back to using two computers as a trial.

Despite all the comments to the contrary, I cannot get two instances of WSJT-X to run reliably. Two versions of MSK144 overload the computer (any computer I use up to my most powerful), and two versions of JT65 run for a while and then one of them get stuck in decode (but stops decoding). So I split them across to computer to see how I would get on.

So far so good. There is no detectable increase in noise, though I have not looked everywhere yet. I may add yet another display screen. I can now run two versions of WSJT-X easily, one on each computer.

I have used a "Smart KM-Link" to allow me to control both computers from one keyboard and mouse. This is a USB device, unlike the older switches which also  switched the monitor. It allows the mouse to move between the screens and automatically switch between them. Apart from some fan noise from the extra PC, the operation of the screens is exactly as before.

This works fine but I struck a problem with the rotator software driving my Yaesu G-600 rotator (the G-450 uses the standard Yaesu mechanical display). The display for my existing software prevents the mouse switching between screens. As I was using the basic software which came with the EA4TX ARS-USB rotator controller ("ARSVCOM"), it was time to switch to some more advanced software.

For some time I have been eyeing PstRotator by YO3DMU. I downloaded it and paid the very reasonable sum of €20 to register it.
PstRotator display - as always click to enlarge if necessary
It does lot more things than I will ever require. First plus is that I now have a choice of 12 presets instead of eight. Not that I can actually think of four more just now, but I have the option. I can enter a locator and the rotator will point there (useful) and even a callsign works too.

This is as far as I need to go with PstRotator for now. It provides lots of options for the future.

We will see whether I stick with two computers as time goes on. However, PstRotator seems worth having.




Sunday, 18 June 2017

A dual-band antenna, 70MHz JT65, and classic rigs

These are the days of the Es season when I change gear. I go into cruise mode.

The "new-ness" of it all has passed. I have no need to work the same station today as I worked yesterday. Others do have this need for some reason. Mostly I sit and watch them all working each other, and I wonder what they have learned since the day before.

Personally, I prefer to look for new squares and new countries. I am of course happy to answer calls if I call CQ, but then I do not spend all day calling CQ. I leave it to others to call CQ continuously. And they do that duty rather well.

True, I have had a few successes in the past few days. IK2MMB (JN45 1382km) was a nice contact on 2m on 16 June. HA/SP7VC (KN17 1866) was a new square on 4m. I really appreciate people activating these rare squares.

It was not so good with an activation from the Nordic VHF meeting in Sweden. The 4m meteor scatter station would have been a new DXCC as well as a new square but it was not to be. I heard them many times, but could not get through. I tried to email them as they did not seem to be sticking to the split they were alleged to be working, but I only got a reply after it was over, and it said that I was too late. Clearly this team put a lot of effort into this activation but sadly I could not work them. Again, for another year. I said that last year.

Also nice have been some contacts on 70MHz JT65. There is no frequency allocated for JT65 on 4m. In fact, the WSJT-X software is supplied with entirely the WRONG preset. It defaults to the WSPR frequency, and every month or two I see people who use this setting this being scolded on the cluster.

Anyway, several people have commented about 4m and I decided to try 70.176. This is not ideal as it falls inside the precious German allocation, but where else to go? I then worked G0XVF and G0MJI, both of whom have been pressing for some JT65 action. Then I was really surprised to work GM4ZMK, also on 4m JT65. This was followed eventually by DL5MCG (JN48 1113km), my first "DX" JT65 contact on 4m. It is not for me to say that 70.176 is the "right" frequency, but I hope that it (or some other one) becomes standardised.

So why do I want to see JT65 on 4m? For the same reason I like it on VHF in general. There seems to be a general lack of interest in data modes amongst some VHF operators. However, JT65 is not just a replacement for SSB or CW, it offers its own special attributes. It is particularly suited to long distance DX working. It was designed for Earth-Moon-Earth use and that is a similar steady low strength situation.

Lately we have had many stations worked from Europe on 6m, as far away as China, Japan and Korea. This, it is suggested, is "Short Path Summer Solstice Propagation" (SPSSP). How this differs from multi-hop Es is subject to discussion. For example, is the frequent path from here to the Caribbean, or the United States or even South America at this time, also SPSSP, or what? Well, in any case, JT65 is brilliant for it. CW also works, SSB is tricky and that is it.

As I write this I am still struck by a station in China who was working streams of Southern European stations on 6m, and who then posted that he was hearing the Angus beacon on 4m well over S9. The Angus beacon in China! Then the posting appeared that Haiti is now available on 4m too (is this official?) plus last year's information that at least one other South American country (was it Colombia?) is also active.

First of all - the 4m Angus beacon was heard in China when there was no 6m path for me. How often would 4m paths be available, perhaps on different trajectories, when 6m is open? How did we not know about SPSSP before a few years ago (i.e. not before JT65)? What can we do with it? Does it extend to 4m regularly, if at all?

I saw an interesing post on a Belgian amateur site. It said that this is a "scientific hobby and not just a communication hobby. In other words, it is not CB". How true. Here we have a genuine scientific discovery in SPSSP, and that beats working the same station on successive days. Well, it does for me anyway.
I have been trying to reduce the number of poles here. Also, my cobbled together ex-dual band beam was in use on 6m, and something had to be done before it fell down in the wind. I seem to have resolved all this, though I now have another dual-band antenna, which was not in the plan to start with. Or two antennas mounted at the same height working on two different bands.

The replacement for the old 6m beam is commercial. Making it into a dual band beam is entirely an FVM invention. It is a Sirio SY50-3. This is the three element version. It is rather well made and should survive the weather here well.

The elements appear to be aluminium tubes with castings for the attachments. The attachments hold the elements using worm screws tightened with an Allen Key (Hex Key). The attachments themselves are pre-fixed to the boom at preset lengths. They are lightweight castings and look very impressive.
Attachment for the reflector on the Sirio SY50-3

The antenna is otherwise conventional, with the dimensions you might expect. The coupling to the coax is via a gamma match, and the recommended tuning settings seemed to work with a low SWR.

I am impressed by the construction. Whilst light weight, it looks sturdy. It took about 90 minutes to build (during which I built it back to front - in some ways I am still like a beginner).

The irony is that I am now about to replace the co-ax to that antenna because it was ruined by water ingress - through a Sirio vertical. Sirio antennas have generally served me well, but their 4m J-pole CX 4-68 seems to have a problem. I was warned that it lets in water, so I double wrapped the joints with self-amalgamating tape. Despite this, it filled with water, which seeped past the PL-259 and into the co-ax. The CX4-68 is a great antenna, but it has this basic flaw.

So, with the new Sirio beam up, and my Sandpiper ring base 5/8th 4m vertical above, where am I to put a 2m vertical? Why do I need a 2m vertical? Good question.

I then took my trusty old dipole, which has been in use here for many years. Over the years it has been altered to serve for 2m, 4m and 6m, horizontal and vertical, fixed and rotatable, portable ... everything. Now it is formed as a 2m dipole and fixed vertically between the driven element and the director of the Sirio 50MHz beam.
Sirio 6m SY50-3, with 2m vertical dipole and Sandpiper 4m 5/8ths vertical
This is a bit difficult to photograph. It is hard to see that the 2m antenna is vertically polarised, and the 6m horizontal. And the stand-off for the 2m antenna is exactly beside the boom on the 6m beam in the horizontal plane, but it never looks like that from the ground.
In reality, the 2m support is beside the 6m boom.
I had done this before of course. You may recall this 2m antenna briefly beside the 4m beam in the past. It may not last much longer this time. It is a lash-up. Any compromise will affect both the 6m beam and the 2m vertical. For now though it is working fine.
"Classic" rigs have quite a following.

Myself, I can do without.

There may have been a "golden era" of amateur radio equipment. It started with commercial SSB transmitters and transceivers. Early Collins, Drake and KW rigs are in this category. Then a series of hybrid transistor/valve rigs from Yaesu and Trio/Kenwood.

However, I would say that rigs from the all-transistor era which followed are not worth resurrecting. Early transistorised rigs have output transistors which are prone to failure (they were dodgy at the time), failing switches, filters going out of alignment, capacitors leaking, resistors cooking ... in fact they are something of a liability. The older ones are similar, but worth fixing thanks to the (hard to find) valves.

Then we had the arrival of surface mount technology at which stage nothing is easily repairable. Unique displays fail and replacements are not available. The chips were discontinued years ago. The switches fall apart. Everything is tiny.

Try to put these rigs on the air and you find the problems. From my point of view drift is the big drawback. These things were designed before we had JT65 and WSPR. They cannot cope. For FM they often have the wrong spacing, the wrong deviation, no CTCSS, noisy synthesisers ...

Are there no classic rigs in the modern era? Possibly the FT-847, a rig I have never owned.

I can see the idea of buying an old VHF rig. They used to be single band, and often they were much loved in their day. There is no such thing as a VHF rig now, so the old ones appeal. In general, they do not fit into the modern shack. For all the reasons above, old rigs are a problem best avoided. The VHF ones seem to be worse as technology has advanced.

They say you appreciate your own old rigs. So it is personal. Yes, my Trio JR-599 would be a classic if I still had it. Or my FT-101s. Or the TS-530 I never had. I recall the KW2000E from the radio club at the Belfast YMCA radio club, and the FT-200 in the Queen's University club. Do I want these now? No thanks.

Key factors for me now - panoramic displays, DSP filtering, ideally SDR architecture, USB digital in/out for data modes, very good frequency stability - all things unheard of in the "good ole days".

So why do these old tubs attract so much interest? Well, the shops like taking them in as trade-ins ("part exchange") and then selling them on. Magazine articles praise them but ignore the problems. Everybody is making money selling them and writing about them, so of course they say they are great. Yes, put one on your shelf. But don't expect it to be much use these days. Turn it on and take a photo with the lights on (if you can get them to work). Then turn it off and admire it. They look great. That's about it in my book.

I can see that true pre-SMD classics are great restoration projects. The repair then is the object, rather than trying to suggest that the restored rig is comparable to anything we might use today.

If there is a classic rig worth having, it was made before 1980 in my view. After that they are just bundles of heartbreak.

They do look nice though. If I wanted to live in a radio museum I would not be working much. Luckily, I want things to work as well, so that is OK by me.

There is room in this hobby for all sorts. Sure, put your old rig on the air. It is not for me though. I will watch you drift past my waterfall. If you can get your receiver to stay put you will see my truthful reply "no decode". Sorry.