Wednesday 24 April 2019

The equipment sale of a silent key amateur caused me doubts

Four or five months ago a local amateur became silent key. I shall not mention his callsign and I shall call him "Roland" here. I do not want to cause any distress.

Roland lived about 20 miles from me in the Tweed Valley. I encountered him 5 or 6 years ago when he came over the GM4FVM a couple of times to see my set-up. He wanted to create something similar as his interest was in VHF, and there are not many others round here doing that. So he phoned me a few times and then came and looked, and later built something similar.

When Roland passed away a fairly common situation arose. Basically his equipment was to be disposed of very quickly by people who did not really know what it was. At this stage I was contacted by his brother in law, also an amateur, to see if I could help. The initial questions surrounded Roland's IC-7100, the purpose of which was unknown to anyone. I went over and explained to his brother in law how it worked.

The next thing which emerged was that everything was to go, and as soon as possible. Roland's 10m Tennamast, 2m, 4m and 6m antennas, rotator and all associated metalwork was taken down and left on his front drive. I was asked about it and I quickly offered the Tennamast to another amateur in the area who I knew was interested in one. However, he only needed a 7m Tenna, so there were no takers. The antennas and the Tennamast were quickly scrapped.

This was a bit of a wake-up call. Coax and rotator cables had been chopped up to get them out of position. The cables for the IC-7100 could not be found, neither could the associated CD, nor various similar items. Large quantities of magazines and paperwork went to the local dump, so different items were being separated from their manuals. I was told that the rotator was headed for the dump.

Faced with this, I was unsure how to act. I did not want to see valuable items being dumped. Roland's widow deserved to get some value for them. The Tennamast had already been assigned for scrap. So I stepped in and bought the rotator, the IC-7100 and an old low-spec oscilloscope. I really had no need for any of these items, but I did not want to see them dumped. I then had to scrabble together a large sum in cash and hand it over, something we don't do much in these days of plastic money.

I had to deal with the issue of how much to pay for some things I didn't really want and I was not even very sure about their history. I had never heard Roland on the air - if he ever transmitted I never heard him, nor had I met anyone who had worked him. Had I not heard him because nothing worked? The amount had to be high enough to make Roland's widow better off than scrapping them or other disposal. I did not want to hear later that these items were sold off too cheaply. The scrap value for the Tenna mast might not have been zero but was certainly very low compared to its true value as a mast. The other items were headed for the dump.

I had to make it very clear that if these items were carefully marketed on eBay they might fetch more, and if they were offered for a straight sale to a dealer they might fetch less than that but more than I might pay. Either way was an option for the estate. In the end, as I say, I bought three items. Some other things found good homes, in particular a rather nice ATU. A couple of small high value items were rescued and remain to be sold, including a DMR handheld and an MFJ antenna analyser, but everything else was thrown away.

I apologise if I have got some details of this wrong, but it all happened very quickly, and a lot of it occurred outside my knowledge. I was not directly involved in most of it. However, it is clear to me that there was no plan as to what to do, and the need to do it quickly probably resulted in high value items being scrapped or thrown away.

Still, some good came of it.
Roland's Yaesu G-450 rotator had to be hastily pressed into service yesterday when the azimuth sensing potentiometer in my G-450 failed. OK, it had sat in my garage for 4 months while I wondered what to do with it, but it came good in the end.

You may notice that my 6 metre antenna has changed again, it is now my old 4m/6m Vine dual band antenna resurrected. Why do I need 2 antennas on 4m? More on that later.

My original 450's pot should be easy to fix but it was very handy having a spare rotator to change over. The job only took just over an hour to do.

If I had any idea what to do with Roland's rotator it was to use the control box as the basis for a plan to use my EA4TX controller to run the G-450. I was working on that when the rotator pot failed. The controller plan wasn't going well by the way, as the voltage on the G-450 azimuth sensing line was very low and too low for the EA4TX unit to reliably measure. Never mind that for now.

And Roland's old IC-7100 is also in use. I did not need another radio. I still don't. The arrival of the IC-7100 might have seen it sit idle like the rotator. As it turns out, the IC-7100 is just what I needed for 70cms, and the rig sitting idle is my IC-7300. Who would ever have thought I would end up with a radio as good as an IC-7300 sitting here doing nothing?  It just proves that I did not need another rig.

The moral of this story? Well, Yaesu rotators break down --- NO --- the moral is that we do need to think about what would happen if we end up going silent key. It is the necessary result of being alive that at some stage life will leave us. Is it fair to abandon our nearest and dearest to sort out what we leave behind? Is a mountain of old gear easily sold off by grieving relatives? Can we provide for this in some better way?

I read an article on this subject a year or so back in QRZ.com. Somebody who had acted for two widows in selling off SK gear had written to say that we should be better prepared. He acted in good faith, and one widow left him to it, the other demanded cash receipts and detailed accounts and justifications for each sale. In an slightly older local case, a couple of amateurs who acted in good faith were later accused of feathering their own nests. I certainly thought they paid fair prices for piles of old and uncertain gear, but the widow later accosted one of them in the street and accused him of under paying. It left everyone feeling uncomfortable.

So I ask this general question - if you were to die tomorrow, would anyone know what to do with your gear? Would they even know what it is? Shouldn't you write down what it is and what to do with it? Should it go on eBay? Should it go to a dealer? Is any one person to be trusted to sell it off? And what if the trusted seller want to buy some themselves? What price is fair then?

I fell sad about the way that Roland left this world. His carefully assembled radio shack was never used for what it was designed for. What did he do in his shack for all those years? His expensive cables were cut up. Some of his gear could not even be identified by the people sent to remove it.

Perhaps it was inevitable that a lifetime's collection of Rad Coms went straight to the paper recycling section of the local dump. But some things that others could have re-used were scrapped. If more had been known, and more time spent on it, I believe that more money could have been recovered. But perhaps more importantly, some gear could still be being used.

I hope that Roland takes a break from operating in that great shack in the air sometimes to look down and see his rotator turning my beam.

73

Jim

GM4FVM

Friday 12 April 2019

"Almost Sporadic E" and 6 metre band readiness

At the start of April we find ourselves back in the "Almost Sporadic E Season".

For the past ten days I have been decoding one-way FT8 signals on 50MHz which look like Sporadic E, and so have others. Sometimes I have called CQ and been heard all over the place ...
Stations reporting hearing GM4FVM on 50MHz, 7 April 2019, on PSK Reporter
All of this has produced just one QSO for me - SP4MPB on 4 April. The rest of the time I just see parts of signals being received. Even more frustratingly, I see myself being reported as heard be other stations, but I hear no replies. Collections of dots and lines which are almost enough to decode but not quite there, then maybe at a different time several decodes. Although I can receive them, none of the stations answer when I call. Lots of activity, even quite a few decodes at time, but only once a QSO.

Almost Sporadic E.

There could be lots of explanations for this, but I think it is all the more noticeable thanks to WSJT-X and that darned mode FT8. I have speculated before about the ability of the "weak signal" modes to receive signals which are otherwise inaudible, and this may exploit the effect of partial reflection in the ionosphere.

http://gm4fvm.blogspot.com/2017/09/8-sept-aurora-and-above-muf-propagation.html

"Above MUF propagation" is a fairly silly expression, but what it means is "above normal MUF propagation", in other words by using very sensitive protocols like FT8 we can decode signals we never noticed before.
Plenty of 6m activity on PSK Reporter, 9 April 2019, no QSOs though.

Partial reflection occurs when there is refraction, but usually we do not notice it because the refraction produces a much stronger signal which swamps the partial reflection. It may cause phase differential QSB, which many of us note on radio signals without giving much thought to the causes. However, just now the E layer is only strong enough to produce some refraction but not enough to deflect the signal back to Earth, so the weaker reflected one is heard.

Partial reflection is really only capable of being understood as a quantum effect. I do not think that I am alone when I say that at school I was taught the wave theory of radio propagation in my physics classes. It is very comforting to think of radio progressing as a wave, especially as many observed radio effects can be explained by wave theory. But wave theory does not explain partial reflection. Like many more complex aspects of elecro-magnetic theory, we need to consider quantum effects to understand it.

When considered in quantum terms, radio energy travels in straight lines carried by photons, and these are only deflected by:-
a) gravity (but the Earth's gravity is too weak to have any significant effect)
b) collision (producing what we know in radio as scattering)
c) refraction (the main way signals are deflected back to Earth)
d) reflection (quite rare at common radio frequencies).
It is in the process of refraction that partial reflection occurs, and it is often dismissed as a byproduct as it is very weak.

You could add to that list e) absorption. Radio signals encountering a very dense object will be effectively absorbed. The object gets hotter, and the photons involved cease to exist. Not really deflection, but worth mentioning. Although there is some absorption (and scattering) in the atmosphere, the radio signals we notice getting weaker do so mostly due to the Inverse Square Law

However, you will note that neither electric nor magnetic fields deflect photons, so neither the ionisation itself, nor the Earth's magnetic field, will deflect a photon in the ionosphere. What we hear back on Earth is almost returned to us due to refraction (plus a tiny element of reflection).

I had written 10 long paragraphs on the subject of the analysis of radio propagation from a quantum perspective. It is all so complex it hardly seems worth it. I have just deleted them. Instead I will show my home drawn diagram from the earlier posting again, and it applies equally to the E-layer as it does to the F-layer:-

The partial reflections, shown by the white lines, would normally be swamped by the main signal, but just now the ionisation is not quite strong enough to refract the main signal back to Earth. So we have some weak reflections, and we would never notice them were it not for using FT8 and other very sensitive modes.

As partial reflection is a quantum effect it happens in the world of probabilities. We can see through glass yet from the correct angle it can reflect light too. Up to 4% of a light beam falling on a single layer of glass is probably reflected by this process. "Up to" and "probably" being key here. The effect we see with glass is faint and ghostly. You have probably seen reflections from glass, when you expect to see through a shop window but also see a faint impression of yourself as a reflection.

In the dire 1960s UK comedy TV series "Harry Worth", Harry used to open the show with a recording of himself reflected in a shop window .... no Jim, don't go back there again. Harry Worth's TV show should be forgotten but, yes, it did feature partial reflection in the titles. Yes, Harry was a bit of an amateur scientist. Anyway, partial reflection is a faint, shadowy event, and that seems to explain what I am hearing.
Harry Worth (the things we used to find funny) Photo Wikipedia (Fair Use).
Sure you can also explain these strange signals in other ways. For example, maybe the ionisation is rapidly variable and just reaching levels able to support refraction. I do not think so, as these signals are very weak (Es is very strong), and there is a one-way element. I can copy one or two or even three signals from station, but they do not hear me at all. At other times different stations hear me and I do not hear them.

If you look at my diagram and imagine another signal coming the other way you can see that the angles do not match up - you could not reverse the angles symmetrically as the path of the signal passing the other way would need to be pass through a different patch of ionisation - and Es clouds are notoriously localised.

Whilst it is possible a second patch of ionisation would occur, or the first one is wide enough, it is unlikely to happen until there is much more ionisation - not until into the Es season proper. If this sounds odd it is due to the asymmetry of the path - the partially refracted signal is not straight, whereas the reflected one is more likely to arrive at a different angle as it passes through different paths of ionised space. While the path my exist, the signal will be a different strength. This effect becomes less as more ionisation occurs.

Certainly there is marked one way propagation in the present period. Soon we will have more ionisation, stronger refraction, and we can forget these odd lumpy traces on our waterfalls.
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In order to be ready, and as predicted in my last posting, I have readied my 6m linear amplifier. I have taken the TE Systems 0552G out of its box, cleaned all the corroded cables, tuned it up, and Hey Presto!, it works. I suspect that the trouble was simply power starvation after the 50 amp drawn through the PSU output terminals melted everything that would melt and scorched and blackened everything else.

I have imposed a current limit of 40 amps, but I can still get 200W output for that so it is no hardship.

As I suggested in the last posting, the three element 50MHz antenna seems to be fine for now. Perhaps by late May I will feel the need for something bigger.

Also mentioned last time, I am investigating more power on 70cms. Not a lot more, but maybe up to 3dB more would help the Earth Moon Earth strike rate a lot.
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At last, thing are beginning to look better for the new season. Well, I did work SP4MPB, so technically the Es season has started and the Lyrids meteor shower should be going soon.

73

Jim
GM4FVM
P.S. I have to post this now, as I have spent so much time drawing diagrams of one-way paths, small patches of ionisation, asymmetry ... grrr ... I am going MAD. Quantum theory, who needs it?