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.
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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 ...
http://www.g3zpf.raota.org/articles/wouxunKG-UV950pl.pdf.

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.
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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.

73

Jim

GM4FVM


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.
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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.
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"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.

73

Jim

Thursday, 8 June 2017

A bit of an Es opening.

"Somehow we have so far avoided those ear-bending days on 4m where your head is spinning after working seven or eight DXCC in half-hour whirlwind of broadcast interference and huge signals. Yes, we have had the broadcast stations, but not a full opening. Not so far. Not here."


Was it only yesterday morning I wrote that on this very blog (check below if you want to read it all)?

There was a bit of an Es opening here yesterday.

Somebody somewhere was listening to my pleas. Must be "The Es Fairy".

It says something that I have not quite assimilated everything yet and only the 2m band contacts have really stuck in my mind. I still have to work out exactly what new squares and so forth I have worked. There are now 40 cards waiting in my in-box at eQSL and I have not had the time to look at them.

Firstly was this opening was on 6m, which I largely avoided due to local QRM. I did a little bit of 6m WSPR to inform me what was going on....
6m WSPR at GM4FVM on 07/06/17
That was nice enough but eventually, late in the evening, the local QRM had gone to bed and I went back on JT65...
6m JT65 contacts at GM4FVM 22:40 to 23:00 on 07/06/17
There were lots of stateside stations on but I was having a bit of a problem with the linear, plus, to be honest, I was not operating at my peak. Past my bedtime.

Most operating was done, as so often here, on 70MHz (4m band).
4m SSB contacts at GM4FVM on 07/06/17
I was pleased to work at least 2 new squares in Germany but I need to analyse it all further. I tried my
"doing the treble" trick (see here). Honestly, I forgot to do it, but a German station was complaining that he heard no 2m opening, so that reminded me!

This worked 100% on this occasion. Moving up from 6m, 4m was open and I knew which way to beam. Coming back down to 4m when 2m had closed, though a technical success, came at a time when I was exhausted. "Brain fade" I think is the modern term. Anyway, I had a pile-up to work through and ended up trying to work a Polish station twice.

Meanwhile, when I was on 2m ....
2m SSB contacts at GM4FVM on 07/06/17
Now this did make me sit up and pay attention. Nine contacts. Four new countries, Ukraine, Czech, Slovakia and Hungary, plus a new square in Poland.

2m Es is different from 4m, and totally different from 6m. It is hectic. Your best hope is exchanging callsign, report and locator as quickly and clearly as you can once. Any hanging about and the other station has faded away. The area covered is small and moves about quickly. Plus, we usually only get an hour or so of it on two or three days in any year. Before I worked out the "treble" approach I almost always missed it. So you have to make it count if you happen to find it. No wonder I was knackered after all this.

It would be easy to relax now and just analyse it all but we are off again today. 4m and 6m have been open into Europe. I spent a long time listening to Japanese stations on 6m. I worked some stations on 6m JT9 and then SSB on 4m. It seems that no recovery time is possible.
VHF contacts at GM4FVM up to 13:30 on 08/06/17
Several of you have sent me your experiences of the 7 June opening. This one from Mike GM3PPE seemed to hit the nail on the head for me ...

I have just had the most amazing opening ever on 6 meters.  Between 1827Z and 1857Z I worked WP2B, WP4JCF, VP2ETE, NP2J and PJ4NX - all about 56, giving me an average of 55.  Just astonishing.  The VP2 was calling CQ and getting no replies.  WP2B peaked a genuine 59 and worked a number of GMs!  I keep saying - just astonishing.  I missed FG4NN who was only about 44 with me and had a massive Eu pile-up calling him.  ...  I see now why they call it the "magic" band!

It just goes to show what can be done with modest equipment and a certain thirst for knowledge. Curiosity, is what I would call it, and it is well repaid when it all goes right.

Well, I guess that today's situation will be different from yesterday's. That is what makes it interesting. That is why I am curious.

73

Jim

GM4FVM (going to lie down and rest)

Wednesday, 7 June 2017

Out of the rat race, bikes, and update

I have been hearing Japanese stations on 6m. Well, most of Europe has been hearing them.

Those that hear them call them, and those that do not hear them call them anyway, just in case.

The pattern here is that I get a decode from one of them, and then nothing more. The path is variable and unpredictable.
JA heard but not worked ...
Sometimes they are quite strong, other times not.

In my book you have to be likely to work a station to justify calling it. So far I have not called any of them.

Of course the path is very critical in these cases. If you are in the right place they are easy to work, if not, all you get is tantalising examples of others calling them for hours at a time and working nobody at all.

On some occasions I have been right along the path of other European stations calling Japan (and China, Korea and Western Russia). The blast is astounding, with my radio going ballistic trying to cope.
Pandemonium breaks out - on this occasion when the 6m path opens between EA8, EA6 and JA (DXMaps)
Added into the mix of stations calling the "Far East" is an equal number of hapless European individuals who are just trying to work other Europeans. This is fun to watch. While listening for weak signals from far away, suddenly a S9 +++ signal plumps itself down 5hz away.

As most of this traffic is on JT65 then all the European local working, and all the DX listening and all the general blasting is all located in the width of a single SSB filter passband. It is possible on CW too, but ....

There is of course a simple answer to fix my difficulty in working Japan. All I need is a 20m+ tower, a rotator to turn it (or maybe just turn lots of antennas), several 8m boom yagis, a 1KW (at least) linear and a top of the range radio. Plus gold plated phono plugs and a nice leather swivel chair for the proud photo in QRZ.com.

No. I am not doing it.

There is absolutely NO possibility of me joining the rat race that drives others to spend ££££ on a project to work Japan in defiance of the conditions. Someday I might work Japan with what I have now, and I will feel vindicated. Maybe not, in which case I will go to my grave happy that there is enough money left in my bank account to pay for a good funeral.

I am not going to go through life unhappy just because I cannot work Japan when I want to.

I am not settling for mediocrity either. There are lots of improvements I can make here which will make long distance working better. I can work with what I have, and identify blockages here and there which get in the way. Rather like the "marginal improvement" programme of the Sky cycling team which saw them win the Tour de France three times. Every little bit counts. Add the little bits together and they make a lot of advantage.

So am I suggesting that Team Sky won the Tour de France with a middling rider but lots of attention to detail? Certainly. The first time anyway. They made up for his weaknesses by learning and developing their strategy. It helped that they had a brilliant team to support him, rather like ancillary items in the shack. Just buying in an expensive (better) rider was not what they did and thus no big tower, kilowatt linear or £8,000 rig for me.

I actually like it this way. It seems to me that the amateur radio world is divided into three camps. Category A has those who have a simple set-up, a wire antenna with a "VHF co-linear" vertical and who shun any further development or learning. At the other end of the scale, Category C pursue their hobby with deep pockets, obsession and determination to out-punch the ionosphere and out-buy anyone who dares to challenge them. And in between is Category B, who are the ones who want to learn and progress beyond the simple, but who stop short of relentless pursuit endless contacts.

I know that I am in Category B, but I only know of two other amateurs in the world who think the way I do. So there are only three of us. Only three of us who cannot stick the mundane boring nature of aimless CQs by the unknowing Category As. And the same three of us have no need of "premium brand" radios, huge linears and towers turned from the bottom which the Category C folks think are essential. We just want to learn from our hobby. All three of us.

Of course those in other categories are perfectly entitled to do whatever they want. You can call CQ for 92 minutes if you like (I saw you). You can spend all you like on whatever gear you want. It is a free world (!). But neither of those options appeal to me.

Let us get this perfectly straight. I rely on the expensive super-stations at the other end of DX paths to pull me through. I also rely on the little stations to get me those rare squares. I am in no position to criticise. I am not criticising. I am just pointing out that my own philosophy is different.

All the same, it feels kind of lonely here in Category B.

Thinking further about this, Category B folks might be in another different group entirely. In this other world there are only two groups. Group 1, the ones who feel that turning on the radio should automatically produce contacts, and Group 2 who want to learn rather than just work people.

Actually, Group 2 is pretty small too.

So what is the next step? Well, a drum of Messi and Paolini Hyperflex 10 co-ax arrived this morning.
75m of M+P Hyperflex 10 waiting to be installed

I was aware of M&P but I had never heard of HyperFlex 10 before David GM4JJJ pointed it out on this blog. Thanks David. It will play a part in a general revamp of antennas to look for a few more marginal improvements.

As for Japan, well it would be nice if it happened but I am not too bothered either way.

What have I learned from this then? I would rather be happy than right, any day.
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Speaking of bikes, the Giro d'Italia was great this year. That dashing handsome man from Sicily (no, not that dashing handsome man from Sicily, the other dashing handsome man from Sicily) Vincenzo Nibali looked set to pip the grumpy little Colombian rider, Nairo Quintana, on the streets of Milan. But it as not to be, for Dutchman Tom Dumoulin triumphed, and this was despite having stopped for a toilet break in the middle of a mountain stage some days earlier. His attack of the skitters cost him two minutes, but Dumoulin still won in the end.

Three weeks of glorious coverage of Italy, and the final result came down to the last five minutes in a terrific final stage. Fabulous.

After more than 90 hours racing, Dumoulin won by 31 seconds. 0.0008%. That is where marginal advantage comes into play. And marginal gains do not make any difference if you are not in the race. You have to compete to be in with a chance of your strategy winning. Then play to your strengths.

What can I watch now? Well, having finished Masterchef Australia 2014, there is now Masterchef Australia 2015, a thirteen week, 65 episode (all an hour long and often more) marathon. How can I do all this and do radio? And then the Tour de France next month. And the cricket. I must cut back on something. Radio maybe?

Life getting in the way of radio? I wonder if maybe that is how it should be.
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You win some and you lose some.

On 6m things looked fairly healthy
50MHz (6m band) contacts at GM4FVM 24 May to 6 June 2017
It was particularly nice to be heard (off the back of my beam) by WP4JCF (FK68 6733km). We then had a QSO and it was great to hear Oscar again. He is the best VHF DX this year. So far.

The ones that got away were two DXCCs I would like to work on 6m, US Virgin Island (WP2B) and Guadeloupe (FG8OJ). I heard both stations quite strongly at different times, but I could not break through the pile ups.

Linears, no thanks, I prefer to deal with the agony.

"Lose some" was particularly noticeable on 70MHz (the 4m band).
70MHz (4m) contacts at GM4FVM 24 May to 6 June 2017
All well and good, but nothing really startling. OH6DX (KP32 1768km) was in a new square for this band. He said I was his first GM on 4m. I remember my first OHs on 4m, seven of them all worked on FM on 15 June 2010.

I also enjoyed working SP4XQS (KO03 1465) on FM on 4 June. I always enjoy FM DX. The idea of working long distance with a simple rig is very appealing, even if (in my opinion) FM in any other situation reduces amateur radio to a very useful telephone service. Where would we be without a telephone service?

Somehow we have so far avoided those ear-bending days on 4m where your head is spinning after working seven or eight DXCC in half-hour whirlwind of broadcast interference and huge signals. Yes, we have had the broadcast stations, but not a full opening. Not so far. Not here.

A possible explanation arose from some details Richard, GI4DOH, sent me about Es. This came via the ARRL and amongst a lot of other information it raised the effect of geomagnetic events on Es. Certainly here for a few days the K number was high and all the Es vanished to points further South. Not that the geomagnetic disturbance stopped it, it just appeared to migrate away from the North. I have noticed this before but maybe there is a link here which needs to be investigated.

I heard that there was a 2m Es opening, which I missed. I must have been doing something else.

Anyway, that is enough for now. There is recorded television to be watched. There is radio to be done.

73

Jim

GM4FVM

Thursday, 25 May 2017

Meet the VHF Linear Amplifiers and general update

In reverse order (as is so often the case here).

Why reversed? Because I am "contrary".

By now (25 May) the Sporadic E ("Es") season is well underway, and every good VHF enthusiast has been filling their boots.

As an example yesterday the Es opening started at 08:44 and ended at 22:40 when I turned off and went to bed. I am not sure how long it went on after that. If you looked during late morning and late afternoon then you missed the best bits. There was a lull from 13:02 to 15:10. A classic two phase day.

I had 350 WSPR spots on 10m, as follows:-
24 hour map of WSPR spots at GM4FVM starting 09:00 24 May 2017
This usually provides a good guide as to where to point the VHF antennas, as well as telling me when it was the right time to go to Morrisons to buy bread (i.e. during the lull). The Seeded Batch is a good loaf and it will be nice with a boiled egg for lunch today. Just waiting for 10m WSPR to tell me when to put the pan of water on to boil. Wait for the lull to start. Don't want to miss ANYTHING.

There is a danger here that a guy could get obsessed. Not me of course.

I had very few contacts on 6m yesterday, and none at all apart from locals on 4m or 2m.
VHF stations worked at GM4FVM on 24 May 2017
I was somewhat hampered by local 6m QRM which blotted out several DX stations which I could hear in the clear. That tends to make me move on to JT9, which is a less popular mode.

The opening on 24 May was notable more for its length than anything remarkable. For example, I worked F1ABL on 6m at 22:00 and SP6IHE on 10m at 22:30. During the QSO, SP6IHE broke off to work a W station and then returned to finish with me. Some stations worked into the US on 6m but not me.

The few days which preceded this produced more variety, including a couple of German stations on 4m. Their 4m authorisation lasts until the end of August though so far I have not heard many, not even on meteor scatter. I am trying a different map background, just to prove to myself that not everybody speaks English.
VHF contacts at GM4FVM 18 to 23 May 2015.
As the Es season progresses I would expect more double hop and more openings on 4m plus possibly the odd one on 2m.

For most of yesterday, apart from calling CQ on 4m, I sat and watched the whole thing unfold. It is a remarkable aspect of nature. You might expect it to move West with the Sun - it doesn't (other than in a vague general way - it opened here due East last thing before I went QRT). You might expect many stations to seek out DX, whereas they seem very happy just to work the shorter distances.

Yesterday it started early and ended late - today it might do the reverse. In fact it probably will do the reverse just for badness, as the one constant feature seems to be that the same thing never happens two days in a row. These are the things about Es that amaze me and keep me watching for hours.

I guess I am just easily amused.

Better still, I spent some time trying to get the tone burst working on my £8 Baofeng 888 handheld. I never even knew it had a tone burst. I had a conversation with Ian, GM4UPX, who knows about them but so far it shows no sign of wanting to turn the tone burst on. It seems to be set by the software (just as well as that rig has no readout nor many controls). Ian says he has got it to work so more conversation there soon.

Then again it was good to hear from Chris, GM4ZJI. Chris has migrated towards 2m satellite operation which is a great idea but I am not there to hear him. Still, he has put up a 4m vertical and we had a "part text/ part phone call/ part QSO". A vertical is a good way to get involved on the Es as well as for FM contacts. Good to hear him too. I look forward to further chats.

Funny really. This is a hobby about communication, but we often sit alone in stuffy little rooms and ponder to ourselves about things. We set up computers or solder things together, and we often forget that conversation is very helpful. At least I have a few sensible people to chat to, and I am grateful for that. The little things matter - Richard, GI4DOH, must have seen me on 10m via the cluster at 23:06 local time last night and he sent a friendly e-mail.

Speak for yourself Jim, not everybody's shack is stuffy.
========================================
My linears are a motley bunch.

There was no strategy behind buying them, and in fact I am not keen on linears much at all.

For Es working, a linear is not that much use. Just like Es, auroral signals are often strong too. Tropo working here is limited by my site and if I cannot hear them there is no point having a linear. It is when it comes to meteor scatter that I felt the need for more power.

Meteor scatter signals can also be quite strong, but only for fractions of a second. They tends to start quite strong and fade away. By using more power you extend the time that the station at the other end can hear your signal. It is this time extension which makes the difference rather than the level of the peak "ping" at the start.

I do not have any 400 watt or larger amplifiers. I simply wanted to raise my power to be in the same order of magnitude as the stations I was working. For meteor scatter this turned out to be 200W on 6m and about 150W on 4m and 2m. I have not found any need to go further.
GM4FVM linear shelf as at April 2017
The photo shows the linears in a previous layout. Since then, as the shelf keeps sagging under the weight, I have moved the 6m linear onto a nearby shelf.

Just about the only thing which they all have in common is that they are all hard wired separately to the PTT line for their various dedicated rigs.

I ended up with this strange line-up mostly by chance. Back when I used transverters for 4m I could produce about 25W output. This was useful on meteor scatter, but not quite enough. I needed something a bit more muckle. So about 5 years ago I bought a TE Systems 0610G 70MHz linear rated at 130W, which happily ran at 100W if I added a pair of cooling fans.
My TE Systems 0610G for 70MHz now sadly sold.
This linear did great service for five years. I had no particular reason to change it, but it was replaced rather by chance.

My previous 6m linear was a Bremi valve CB linear converted for 50MHz. When I finally got fed up with the instability and unreliability of this vintage monster I decided to buy a Linear Amp Gemini 4 to replace it.

The Gemini claims to produce 270W on 6m, with me hoping to use about 200W for meteor scatter. While I was waiting for it to arrive I contacted a GM operator who had one, just to ask about it. He mentioned that he had a 375W 50MHz TE Systems 0552G which he was not using. I quickly arranged to buy that amplifier and it is the one on the left on the shelf. The Gemini then took up its place on the right as the 4m amplifier. So the Gemini replaced the 70MHz TE and its 300W theoretical maximum output allows me to raise my 4m power to 150W. In between is a Microset SR200 2m amplifier which I use at about 150W.

The Gemini comes complete with integral mains power supply and (noisy) fans. The TE linear, on the other hand, comes with a 12V input and no fans. The TE handbook states that with a high duty cycle mode you should fit fans controlled by a 12V TX output available from the socket on the back. It recommends using a timing circuit to keep the fans running for longer than just the TX periods. Being a good amateur who does what he is told, I tried to fit a timed relay only to find that the 12V output from the linear could not provide enough current to lift the relay I had.  At this point it seemed simpler to follow GM4JJJs suggestion and make the fans temperature controlled.

Cheap temperature controlled relays are available from eBay for about £4. These allow you to set a desired maximum temperature as measured by a remote wired sensor which I placed at the bottom of the linear heat sink near the output device fixings. The LED readout on the chip allows you to set your desired temperature and it then switches the fans to maintain the range to within 2 degrees C of the desired level. In my case I set it to 25C. At that temperature setting the fans come on within a minute of my first transmission and stay on continuously until after I have finished.
Cheap temperature control relay from eBay being fitted into an ABS box

It is a simple matter to fit the temperature board into a box, which you can equip with all the sockets you need. In my case, probably unwisely, I use phono plugs for DC supply leads, the fan leads and the TX 12V output from the linear. It might be best to use different plugs to avoid some wiring mix-up catastrophe but that seems to be my standard now. I make clear labels and hope that I read them! There are several sockets on the box for my fans and one which I use to illuminate the backlight on my 6m power meter. I cannot hear the fans so it is useful to have a visual indication that they are likely to be working.

When I comes to fans I really dislike the standard 80mm PC fans. I find them noisy and ineffective. For the TE Systems linear I use four 120mm fans. At 200W output this finds an equilibrium temperature of around 30C. At the quoted maximum for the TE 0552 is 375W, at which point it is drawing well over 50 amps from the power supply, it is running at about 33C thanks to the fans. Whilst the linear would be happy at 375W on SSB, on modes with 1 minute TX times it gets rather too warm internally.

I suppose if I went for screaming small diameter fans moving the air more quickly I could use more than 200W, but I prefer to under-run the linear at 200W. That way it stays nice and cool, (hopefully) linear and the power supply remains happy providing about 36 amps. The over-temperature switch fitted as standard inside the linear trips at 65C.

So that is the TE Systems 0552G. It runs happily and fairly cool at 200W. Apart from the switch panel supply failing as soon as I got it (the repair for which was described earlier in this blog) it seems to do well. Whatever caused the supply to fail to the switching circuit, I think that is also the cause of the lack of current available to switch the fans.  My bet is that despite what they say in the handbook, it is not capable of powering fans via the socket at the back for long before something fuses. Still, that is solved now.

It couldn't be that you put in too thin wire when you fixed the problem Jim? Aw no, that would be impossible.

TE might have used a socket type in more general use for PTT than the RJ45 socket they now use as standard. I built a break-out box for the PTT and fan supply. It might also have had "N-type" RF sockets. It might even have had the necessary fans already fitted (though a continuous duty rack version with fans is available). It had none of these things. I bought it second hand and so far to does the job nicely.

Moving on to the Linear Amp Gemini 4, it was bought initially for 50MHz use. As the TE linear turned up, I moved it to 70MHz. There it runs happily at 150W. It is self-contained, causes no heartache and runs away needing very little attention.

Drawbacks, well it is noisy, with the transformer, fans and the changeover relay all contributing. On SSB it is possible to trip the overdrive cut-out on speech peaks early in the transmission. I am pretty sure that this problem stems from an initial spike in the IC-7300 output. Reducing the power setting on the 7300 seems to function via the ALC. This arrangement can allow instantaneous spikes at the start of a tx period. This is a common issue with many rigs. If I set up the 7300 carefully enough it is not a snag, and it only affects SSB. I know another amateur who has the same issue with the Gemini, and others who do not. To my mind, this is a rig issue rather than a linear amplifier problem. That does not explain why two stations with the same rig and amplifier have different experiences, but then, am I am expected to explain all the mysteries of the Universe?

There is a simple reason why the spikes were never a problem with the TE Systems linears. TE Systems have no protection circuits apart from an over-temperature cut-out. You can never trip the overdrive limit by transmitting a spike into the TE Systems Linear because it has no overdrive limiter. Nor does it have a high SWR cut-out like the Gemini. You take a risk using linears with no protection, and I read that the TE Systems amplifiers have been prone to problems for this reason.

Dealing lastly with the linear in the middle, we turn to the Microset SR200. This is a 200W rated 2m linear. It has overdrive and high SWR protection. To produce the rated 200W output it needs about 50W drive. Like the TE Systems linears it has a built in GaAsFET preamplifier, but in both cases you can switch them out of circuit independently of the PA TX stage.

I bought the SR200 direct from Italy, and at the time I saved about 20% of the UK list price. In the four years or so since then it has worked without drawing any attention to itself. It never failed like the TE, nor tripped like the Gemini. It has always just worked away to itself.

The drawbacks for the Microset include that it needs to have fans fitted for high duty cycle operation. It never gets very hot, but then I never draw full rated power. It does not have a fan control output, so I will be installing another temperature control to its fans. For once I am going to try a variable speed control and we will see how that goes. You can buy fans with integral temperature control and remote sensors which I will try, though these have preset temperature ranges. I will be changing over to 120mm diameter fans at the same time. In the past I used the Microset with 2 small and 1 large fans with nothing more complex than a switch.

Strangely for a high-VHF item, the Mircoset is fitted with SO239 RF sockets rather than "N-type". These are easily changed.

I use the same 12V power supply for the Microset linear as  I use for the 6m one. This could be a problem if I accidentally transmitted on both at once, but that has never happened yet.

So back to the start. Why do I have linears? Because nobody can use a commercial rig at full output on meteor scatter QSOs and expect it to survive at full rated power. I drive the 6m linear with 8 W for 200W output, meaning that the rig only needs to run at less than 10% of its rated out (and the linear at just over 50% with added fans). On 4m it is 8W for 150W output, using just 16% of the rig's output (and again using only 50% of the linear's rated power). On 2m the rig provides about 25W. To try to get a lot of power from a rig on a regular basis is risking a very expensive item for little benefit.

Also, none of the linears is working near its full rated power. If, say, you took the manufacturers advice and drove the Gemini and TE with 25W and the Microset with 50W, you might get away without overheating them on SSB. However, you risk pushing them into non-linearity. Personally I set them up using a power meter, checking full power output and then backing the power off to well below the maximum possible, and ideally to 50 to 75% of the maximum.

To me anyway, linearity is very important. I do not wish to get a bad name for over-driving a linear amplifier. The drive levels quoted by a manufacturer will be maximum figures, and my meters are not sufficiently accurate to ensure that I do not overdrive the amplifier. So I tend to back everything off - and it saves the rig too.

There was a magazine article recently which tried to suggest that everyone should have a linear and run full legal power. It suggested that this was our duty as amateurs as otherwise our legal power limits would be cut. Well, if that is the case I am failing in my duty.

There is a school of thought that says that more power is just better in every situation. Sorry, but at 200W I have gone as far as I ever need or want to go.

I suppose therefore there is no logic in my choice of amplifier or the use I put them to. For now though I am fairly satisfied with them, and the results they deliver.

73

Jim

Thursday, 18 May 2017

Some more thoughts on JT65 as Es gets under way

1) The two phase theory
Someone asked me what time of the day he should look for Es.

It is often said that Es features two peaks during the day. I have already said that my examination of my logs shows no distinct pattern, though despite this I do think that the two phase theory has some usefulness.

So what am I on about? Well, of course Es is sporadic, and some days there is none (no phase at all), some days there is Es only in the morning or afternoon, or even the evening or night (one phase). And sometimes there are two distinct phases with a lull in between.

Recently we had an example where Es first appeared around 08:00. It carried on until about 13:00, then faded to return at about 17:00. So two phases could be noted, on that one day. The difficulty in trying to interpret this is that on one day the first phase might start at 12:00 and finish at 14:30, whereas on a different day the second phase might begin at 15:00.

How is the possibility of this two phase characteristic useful? Consider a day when I am working Es and at, say 13:00 it fades out. My 28MHz WSPR station goes quiet. All the Es clouds fade from the Es MUF on DX Maps. I can then do some of the more important things in life, such as perhaps writing my will, or changing the wheel on a wheelbarrow. I can be fairly sure that there will be no Es for about 2 hours. Maybe three hours, or it might not come back, you never know, but there is a definite gap.

The Es may have faded that day at 12:00 and I will be looking for a return later, maybe after 15:00. But on another day it might only fade at 15:00, in which case the clock starts from there.

So the concept is useful in knowing when there will probably not be an Es opening, rather than when there will be. There generally will not be another phase right after the current one fades out.

It seems to be impossible to predict (reliably) when the Es will start or finish. However, when it fades it does not come back for a couple of hours. Or so it seems to me. There might be  no second phase that day, but I know I have some time to do other things before I need to worry about listening again.

Let us imagine I have some gardening duty to do. I would routinely look in at the radio in case there is some Es about in the morning. If there is I can put off the gardening until the gap between the two phases. It is very unusual for Es to run for the full day, as otherwise I would never do any gardening. And that would be terrible.

It is said that we should look for Es in "late morning or late afternoon". After I read that I worked into Greece at 09:25. (Nice contact by the way, SV9CVY in KM25, 3091km. I have worked him before, but still a good one). That was not "late morning". Also not "late afternoon" was a contact with SM5CNQ (JO78) the following day at 22:21. You cannot make too much of one or two contacts, but looking earlier than "late morning" and later than "late afternoon" proved worthwhile there. They have a general point, there does seem to be a lull, but trying to pin it down like that is tricky.

If there is supposed to be a lull in early afternoon every day, I have already worked stations on Es at 13:25, 14:42 and 14:50 (F6ECI, OE5OLL, and EB1AO), which suggests otherwise.

So far, 37% of my contacts have been outside the "late morning, late afternoon" slot. I just think that it is not helpful to put labels like that on Es, which might have the effect of limiting the times people operate and thus causing them to miss useful contacts. 37% of useful contacts, indeed.

For this year's Es season, only one day so far has had a "classic" two phase double peak.

As always, I need to say that this is what happens at this QTH, it might be different where you are, especially if you are in tropical regions.

I cannot predict when to listen for Es. I cannot say that if the morning Es has faded out that there will be a second phase. However, if there is a second phase there will often be a long gap in between. The useful thing is that you know that you can go and do something else for a while.

Given that both wheelbarrows now have new wheels, what else can I do?
=========================================
2) When to send you locator on JT65, and when to send 73?

Especially on VHF, JT65 can be an unwieldy beast. It takes six minutes between sending your CQ and sending it the next after having a QSO. In six minutes the propagation can have come and gone.
There is a shorthand way of doing this. I do not have any from today to show you, but I found this one in the FVM vaults, showing some Winter Es:
It may need to be clicked on to enlarged.

It goes :-
1) CQ GM4FVM
2) GM4FVM OH6WD +14dB (not his callsign and locator)
3) OH6WD GM4FVM R+05
4) GM4FVM OH6WD RRR

That would save 2 minutes if I left it there. In the short Es openings which we get, 4 minutes is probably long enough.

However, I was still stuck with the idea that I should complete the QSO in the classic way, and I sent OH6WD GM4FVM 73. That was silly. I should have gone on to call CQ again. If I did that, OH6WD would have realised that I had got his RRR, as otherwise I would have repeated my report.

If you reply to a CQ without sending your locator, but go straight to the report, the station at the other end does not know where to point their beam (if they are using a beam). It will also set the QSO off on the opposite segment, so you are giving your report and RRR when otherwise you would just be giving the report, and the whole thing ends 2 segments early if you do not send 73. If you do send73 you find yourself listening to silence for a minute when you could have been doing something more useful.

Coming from HF JT65 you might find all this a bit brutal and dare I say it, impolite. Coming as I do from VHF meteor scatter, it is quite common. When your QSO could last over an hour to confirm six pieces of information you are accustomed to short cuts.

The way I make sense of the example above as follows:-

1) I had worked OH6WD before, so he can feel free not to send his locator.
2) If he can take a shortcut like that, he will assume that me calling CQ at the end is the same as the 73 message - I have your RRR and I am moving on. Otherwise I would have repeated the previous message.

I personally would only skip the locator if I had worked the station before. For example, I have worked OZ1JXY 65 times now, and he knows where I am.

By the same token, I would always accept seeing a CQ as a confirmation that the QSO is finished. I do not need to exchange 73s if it takes 2 minutes to do it, and especially as I already have his report and his R, and I have confirmed this by sending RRR.

However, if the QSO progresses the normal way then the 73 costs nothing in terms of time, so I will send it. It is his frequency and it is up to him to call CQ next, so I fill the empty space with a 73. If I reckon I have the time I always do the whole thing by the book, 73s and all.

Polite, what, what?

What I need for a QSO is

1) his callsign
2) his report
3) "R" to indicate he has my details

The locator is required if it is the first time I have worked him from that QTH, otherwise I can live without it. 73 is nice but not required if the other station goes on to transmit again.

Contests, of course, are different.

If I ever do skip the 73 and the other station fails to hear my CQ, then I send a 73. It is what I do, but I see from several QRZ.com postings "you are wasting your time!". Now where did I hear that before? Buggleskelly, where the Porter told Will Hay all about it n the 1937 film "Oh! Mr Porter". That film was based on an original play by the great Arnold Ridley.

Ah well. You remember things like that if wheelbarrow wheels are the only other things you have to think about.
==================================
3) Keep your head when all around are losing theirs.
During a strong opening, JT65 here turns into a bear pit. I have three locals within 5km of here, and when they come on I have little choice but to fall in line with whatever segment they are transmitting on. So long as we all stay together on first or second, and none of the four of us changes, then we are fine.

The snag here of course is that the best DX might be on the same segment. There is no rule applying to Es, as there is on meteor scatter, that beaming South and East is second, and beaming North and West is first. In any case, none of the locals has a directional antenna.

If I can work round this, I do. It is tricky though, with strong signals inside the SSB filter. There is not much you can do about it.

I often turn to JT9. There are not so many stations on it, but it is theoretically 2dB better than JT65 and it puts the locals outside my filter. You can often see JT9 signals appearing at the top of the JT65 waterfall. I find that JT9 is a useful mode to have.
======================================
4) The last few days
13 to 18 May 2017 50 and 70 MHz Es contacts at GM4FVM
Nothing to complain about there, though I missed openings into the Middle East and across the Atlantic. Not that I am the complaining type. I am a cheery, "get along with things" person. But there has been another major aurora warning and yet again nothing has happened yet. Maybe today. This seems to happen a lot lately, the conditions seem right for an aurora but nothing happens.

Ah well, even though there is a ton of Es out there to be worked, you just have to make the best of things.

😁


73

Jim

GM4FVM

Friday, 12 May 2017

JT65 Conundrum continues

In the interest of science, and at some personal cost to my energy levels later, I rose this morning in time to see how I would get on trying to see if DK8NE would hear my signal.
In fact, I had been reported earlier but I missed it.
Careful inspection that image, if you click to enlarge it, shows that I was reported at 04:10 too.

I would expect that at 04:10 there would not be so many aircraft around, and not much Es either.

You do not usually get me in the shack at that time either, and this sacrifice on my part for the benefit of science is something I will not let anyone forget in a hurry.

26 times I have been spotted by DK8NE since 1 May, but I have not worked or been heard by any other German station.

Not that I am paranoid, but I can see why people think that there is someone listening to their phone ...

I was even spotted when I was beaming East (again, today).

I had one decode each from two other stations today and worked no 6m Es at all, but I still managed to be clocked by DK8NE ten times. I cannot work anyone anywhere with a beam, but DK8NE can receive me fine all day on his loop.

To say that I was spotted ten times actually means I called CQ ten times, and I was spotted ten times. The only occasions I was not spotted was when I cut the power or after 15:19.


Some things I seem to have established.

1) No contact so far after 15:19 on any day. Not yet anyway, but I know it works fine at 04:10.

2) I tried WSPR from 21:00 last night until 04:08 this morning. Although G4CPD was hearing me, and DK8NE was hearing local stations (so both stations were working), there was no result after 6 hours. The power level on WSPR was just a bit over 20 watts, the most that I felt I could comfortably run overnight. Probably not enough power for a fair test.

3) I have poured over information on radio horizons for aircraft. From the figures I have seen so far an aircraft at 30,000 feet is too low for a path of 1000km. However, at 39,000 feet it might be possible. The site conditions at each end are hard to factor in, especially with Ayton Hill cutting me off in that direction. This is not my field of expertise (what is?) so I may have got the calculations totally wrong. Let's say that any idea I had of ruling out aircraft scatter on path grounds alone is looking shaky.

4) Multiple modes have been suggested. Yes, I can see how one propagation method can feed into another. However, for this to keep happening 10 times spread over an 11 hour period is a bit of a tricky scenario for me to envisage.

Does any of this matter?
No, not really. It could be aircraft scatter, or it could be ionoscatter, troposcatter, or a combination, or something else. The odd thing is that the path exists for so much of the day, plus it does not coincide with Es or any other opening.

I think, having got this far, I should shut my investigation down for now and see how things go over the next few weeks. Either it will stop, or something will emerge which pins it down once and for all.

I am certainly not trying again at 04:10 tomorrow.

73

Jim

GM4FVM