Tuesday 23 October 2018

Galashiels Rally and how you should spend your money on VHF

Last weekend I visited to Galashiels rally. I should have taken a photo but it never occurred to me. Anyway there were plenty of people there and various trade stands. I bought a solder sucker (90p), a switched mains plug (£1.60), two fixings for wire antennas (50p) and a rather flash loud speaker for £6.00. This was all swamped by the fuel to get there and back, which I estimate at £10.00, plus an hour's drive there and another hour back. You see, I compare all costs and all benefits.

"He is mean".

It was worth it though to meet various people, including a couple of hams who I have worked before but not met. I enjoyed a chat with Dick GM4PPT who is a stalwart of VHF operation, and Robin, GM7PKT, who I have contacted quite a few times on FT8 on the 144MHz band. What both these amateurs have in common is that the paths between us are very difficult due to the mountainous terrain. So it was good to have the time to chat.

Robin's experiences with FT8 are very like mine. In fact the mountains which surround him are much taller than the hills I have to deal with. Despite this he is having success with FT8. This, and comments on this blog, all make me ponder about the success we have been having with FT8. I was a regular user of JT65 and JT9 before FT8 and somehow I never seemed to do as well with those modes, The facts though are that FT8 is slightly less sensitive than those modes. I suspect that a lot of it is due to the greater take-up of FT8 on VHF.

Also at the rally were a lot of second hand radios. There were the usual rather ancient VHF rigs, but there was also a rather neat looking Icon IC-7100, the very rig I was claiming is quite good value at £700. There it was at £550. And they didn't sell it during the rally so I asked how to buy it afterwards just in case.

At the same time I met another amateur who had brought a year old 2m and 70cm radio which he was offering for sale at £35 and eventually he took £33 for it. He then tried to buy a 40 year old 2m FDK for £25. Here he was bringing a perfectly good modern radio and trying to upgrade to an ancient one. He admitted to me that the FDK was very large and would probably not fit in his car. I asked him why he would make a swop like that and he said "nostalgia". In the end somebody else bought the FDK from under his nose - no doubt soon to find that it doesn't have CTCSS or 12.5kHz channel spacing and it is pretty deaf anyway.

Thinking a bit more about all this, I have come up with my own theoretical "law of diminishing returns". This is entirely non-scientific and definitely not a law. It is just my theory about how to best spend money. It was prompted by the experiences at Galashiels and also one particular local who has an interesting approach to VHF operation. The guy in question has outdoor HF antennas, and used to be a keen VHF dxer. For VHF now he uses an indoor quarter wave whip on a magnetic mobile base, stuck onto a biscuit tin lid.

I cannot help feeling that running a radio into a quarter wave vertical and using a biscuit tin lid for a "ground plane" is not a really good use of resources. So I have come up with a graph to represent my law of diminishing returns (which, again, isn't a law). The graph shows a better way of gaining returns for your money be showing an alternative red line.

The idea is that if you use an indoor vertical it doesn't matter how much you spend on a better rig it makes little difference. Your money is better spent on ancillaries like masts and antennas, or coax and pre-amps. Well, that is my view.

Of course lots of people have problems putting up large outside antennas (though the biscuit tin lid guy can as he has HF ones), or have planning issues, but it might be worth a try with something simple - more than buying a new radio anyway. Even if you go portable because you cannot get a good antenna up at home the same general rule applies, so long as you can lug the associated gear out to your portable site. It will usually make your station work better than the same investment in a fancy radio.
The GM4FVM VHF cost/benefit graph (aren't results measured in "JIMMYs"?)
 You will probably need to click on this to enlarge it enough to see it.

I am suggesting that after you have got a "new" multimode (by which I mean modern, the second hand IC-7100 at Gala show would do at £550 and save you some dough for antennas), spending more on radios just keeps you nearly flat on the dotted line. You will have diminishing returns in that there still is a return, a better rig is a better rig, but you get less benefit in term of results for the £££ you spend now than on your basic radio. On the other hand, spending on other things (along the red line) brings you steady returns. I have found that spending a £ on the red line brings a considerable result, whereas spending a £ on the dotted line seems to do very little..

Who am I to tell people how to spend their money?

I have no right to suggest all this, but I do believe that you get a lot more return out of improving your station generally rather than improving your radio. Yet at Galashiels nobody was selling yagi antennas, good co-ax or masts (well, there was one old but nice second hand Clarke pump up mast which I looked at for a long time!).

So what is the way I am measuring "results"? Well, based on my experience - locator squares, distance, countries, surprise long distance contacts, learning about propagation, lots of things. I never said my theory was scientific.

Hey, results are measured in units of increased utility (work that one out).

As for my order of things to improve, well that is based on what I see going on around me. A gable end mast is just a pair of T and K brackets attached by expanding masonry bolts into the end wall of a house - fine if you have a masonry end wall, but there are other ways of doing it. If you have a vertical, get it into the clear and as high as you can using a gable end mast. Ideally use something like a half wave which does not need a biscuit tin to ground it. Next thing is a directional antenna, even if it has to be turned by hand. We used to have TV rotators but nobody has made one that passes the CE test so they are not available in Europe at present. Rotators are simple things, just a motor and a gear box and you can usually get them cheap second hand.

Here is s simple example. For a while I used a vertical on 50MHz. I did very well during the sporadic E season. Then I got an HB9CV (the Diamond one) mounted on a simple bracket cadged off a neighbour and supported by 1.5 inch thick-walled alloy tubes. With the vertical I could work Europe; once I had the HB9CV I could work across the Atlantic. It wasn't easy, but it was possible.
Simple, HB9CV, old TV rotator, good enough to work Puerto Rico on 6m.
The step up in results from a vertical to a directional beam, even a simple one, was huge and far greater than any investment in radios or linears could have done. I was very chuffed when I worked across the Atlantic for the first time. That antenna opened the door to meteor scatter and aurora work too. Better antennas are better on receive as well, so they beat linear amplifiers by a mile.

After that, a better antenna - I am not suggesting that your first steps in improving your antenna are likely to be your last. I certainly have tried my first setup and then upgraded in every case (except, so far, 70cms). As you know, none of my current antennas has a boom longer than 3m and that is enough for me. My advice is to pay little attention to the number of elements and more to the length of the boom (the HB9CV being an honourable exception).

It cost a bit, but I found a tilt-over, crank-up, mast to be very valuable - also more valuable than a linear. For VHF use it allowed me to get to twice the height over the ground of the gable end type of fixing. Partly getting a tilt-over is due to me getting older and less about to climb and haul things about up ladders. Also I live in a wild and windy place. Once again a wall-fixed tilt-over mast is enough for me, free standing masts are a step too far here.

Whilst I rank the free-standing mast as being more useful than a small linear, I don't rate big linears anywhere. I do not see the need for full legal output anyway, and I am content with moderate power. After a while barefoot is not enough, but I am happy to look in the magazine at what the contest operators are using and get with about 3dB of majority are using.

Better coax. A lesson we all have to learn one way or the other. It is expensive but it is worth it and in my book worth more than the same amount of money spent on the radio. Coax does not last for ever, and when you need to change it there is a chance to improve it. A mast head pre-amp - the final essential item on my list to a achieve best results, something to bring your receive performance into line with your transmitting ability.

Then, maybe, someday, a better radio. I like better radios, but I am kidding myself if I was to claim that they really get much better results.

I bet I am criticised for saying all this. If it was not for the subsidy the amateur radio magazines receive from equipment sellers advertising really expensive radios then we wouldn't have a radio press. And we all love a nice radio, including me. Yet when I want to buy a £200 mast head pre-amp I had a devil of a job finding somebody to sell me one, whereas I can buy a TS-890 at £3999.95 (carriage extra) - reduced from £4299 - a snip - anywhere.

By all means spend your hard-earned money on a shiny new radio. But please, think about climbing the red line first.

"There he goes again - off on his hobby-horse."

"I bet he buys some fancy radio soon - he is just softening us up."

73

Jim
GM4FVM

2 comments:

  1. A good article Jim, you're not mean, just canny ;0)

    Agreed though that a beam, decent mast and coax fed into a not so good radio will beat a top end radio fed into a quarter wave on a biscuit tin.

    I should practice what I preach though but alas other commitments get in the way. I am reduced to being a tinkerer!

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  2. Lest it be said that I am trying to act as the Radio Police (heaven forfend) I just want to point out that tinkerers are fine with me.
    Lots of people don't have the spare time I have, Indeed many cannot possibly put up a reasonable antenna, nor maybe the cash to do it. That is just fine with me. What gets my goat are those who could do things but choose to do nothing and then blame everybody but themselves.
    Gav, you are not in my sights. Everybody doing their best in this hobby is welcome to be here in my view. 73. Jim

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