[UK-CONTEST] UK-Contest Digest, Vol 109, Issue 49

[Ken Eastty]

I accept (more or less) the arguments about feeder loss, whether 'power at the antenna' is good idea or not is a different matter (how many people actually measure feeder loss?).
At V/UHF those who are able to erect big antenna arrays gain on both TX&  RX but some apparently still find it necessary to employ 2kW amplifiers using 'feeder loss' as a justification.
I would like to see station details published with more transparency, details given like 'Yaesu, Kenwood or Icom (take your pick) plus transverter O/P 400W etc.' are unacceptable. How many transverters are there that produce 400W? Either the make of the PA or the final o/p device(s) should be included&  since feeder loss comes into the equation the type&  length of feeder should also be declared.

73...

Ken

G3LVP

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> Message: 2
> Date: Tue, 31 Jan 2012 21:14:55 +0000
> From: Chris G3SJJ<g3sjj at btinternet.com>
> Subject: Re: [UK-CONTEST] Output power
> Cc: uk-contest at contesting.com
> Message-ID:<4F2859CF.3020102 at btinternet.com>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
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> Exactly Derek, nicely explained.
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> As I wrote the original comment I will add some more info as it seems the concept of "System Loss" is something many amateurs don't understand.
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> The "system" here is 100m of W103 from the shack in the house down the paddock to the main mast. At the base of which  is a metal box which houses the
> WX0B SixPak remote relay switch, then two runs, approx 20m each, of RG213 to the 80/160m dipole and A4S beam. In total there are 6 PL259s, plus one
> back to back connector to join the two ends which I sliced through with the mower
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> I estimate the "system loss" on 160m to be around 1dB absolute minimum, may be more if you reckon the connectors have been installed over 5 years and
> are not particularly well protected. According to the RSGB Radio Data Reference Book Third Edition, complied by George Jessop G6JP, CEng, MIERE, 1 dB
> is a power ratio of 1.26. Perhaps my interpretation is wrong, but I have assumed that to get 400 w to the antenna I would need to drive it with 500w.
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> 73 Chris G3SJJ
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