Tuesday, 12 July 2016

Mirfield Quad Band Vertical - I cannot even give it away

WARNING - This posting ends with complex and obscure surreal metaphors based on the lyrics of a song released in 1968 and a mysterious and secretive baker of fruit filled sweet rolls who vanished at the same time. If you do not understand the references you weren't around in the aftermath of the  Summer of Love.

This is probably my last posting about this antenna before I break it up for parts.

As you may recall this antenna seemed like a good idea but the SWR was high and the performance not good. So I sent it back.

When it was returned from Mirfield, inside I found a note telling me the SWR results I should be getting. Nothing else seemed to have changed and I had already explained when I sent it that I could not get those SWR figures. So really I was not much wiser.

Being at a loss and knowing that GM6ZFI was looking for a vertical for 2m and 70cms I suggested to him that he might like it. I explained that I had not tried it much on 2m or 70cm, but the SWR was better there and it should work better on the higher bands. At least the length of the antenna then was somewhere near a multiple of a quarter wave.

Doug sped off with it and put it on his mast. Immediately his signal strength here dropped from S8 to just opening the squelch. I could just about hear him but I could not make out anything he was saying. It was the same story with my signal. After a few days Doug returned it to me saying that he could not get any acceptable results with it. Even though I had given it to him, he would rather return it as it was no use to him.

After he took it down and went back to his normal set-up I could work him again fine.

It was interesting to be on the receiving end of an antenna experiment, but a bit of a pity that he would not even take it away for free.

Doug's advice was that I should return it to Mirfield. I have already tried sending it back and it just came back after 6 weeks with the note in the package telling me what I should be getting. No amount of experimentation here came anywhere near those SWR figures.

So I guess I am stuck with it. No point putting it up, so it is leaning against the garage wall still in the cardboard tube it arrived in ...

I cannot really see the point in trying again. Why should I send it back again? I have already paid to send it back once and when you take into account my drive to the Post Office, and what I might otherwise do with the time I would spend on it, I guess I can only write it off.

I need to remember that if something looks too good to be true it probably is too good to be true. Antennas as short as a quarter wave are not going to be very good, and ideally when it comes to VHF verticals, they need to be longer than that. Most people use half waves, 5/8ths or longer co-linears.

If it had worked for me, it would have been the shortest vertical I have ever built or used on 2m, and it was supposed to work at 50 and 70 MHz despite being 1.2m metres long. Worth a try I guess, but it simply lacks the performance I need.

I might move it round the corner inside the garage, and eventually use up the brackets and fittings for home-brewing. What a round-about way to get antenna hardware.

However, like the cake in MacArthur Park, perhaps I should just leave it out in the rain.

It does not really matter how long it took to bake it. I don't like the recipe. I prefer Fig Rolls anyway.

Come to think of it, the Donna Summer version beats the Richard Harris version any day.

Does Jim Figgerty have a callsign?

73

Jim
GM4FVM

2 comments:

  1. Still prefer the Richard Harris version. Sad to say that I remember the 1960s - so I might not have been there (or was I?).

    I have repeated my comment on the previous blog page with apologies. Your findings are probably much the same as mine.

    VSWR was acceptable for me on 70, 2 and 4, but around 3:1 on 6. I have an arrangement with Mirfield to return the antenna at the Kempton Park radio fair on 30 Apr 17. Incidentally, I did see a comment somewhere that suggested that the antenna consists of a resistor with a wire above, which would explain the VSWR results, but leaves the capability to radiate satisfactorily in some doubt. I cannot confirm this finding, however, not being willing to lose £60 in the pursuit of experimentation.

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  2. Ah Keith, Richard Harris had a voice that sounded like a cinder under a door. I don't remember too much else about 1968 apart from riots in Paris, but I do recall Watney's Red Barrel. Watney's Red as it had become when I got to know it. Strange what you recall.
    But you are spot on about the antenna. "Leaves the capability to radiate satisfactorily in some doubt" - great expression which hits the nail very much on the soggy cake (as they might have said on "I'm Sorry I'll Read That Again" - a 1968 Bill Oddie reference). I cannot confirm it either but I suspect it is built that way.
    My KW/Decca dummy load has a geat SWR but it does not radiate much. £60 is too much to lose, but it still lurks here. I did bring it in out of the rain, but only to save the cardboard tube.
    Sorry to hear you had problems too. If it was me, I would turn it into £60 as arranged. Then you can buy a copy of "Endless Summer - Donna Summer's Greatest Hits" to see what I mean. Now I wonder what she was on about. She always seemed to put a lot of effort into things.
    MacArthur Park isn't on that record anyway. I wonder why.
    Jim

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