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G0FTD > ANTENA 13.04.06 02:17l 42 Lines 1603 Bytes #999 (0) @ WW
BID : AC4309G0FTD
Read: OE5AKM DL6DBA DL5SFI GUEST
Subj: Short vertical balun trick
Path: DB0FHN<DB0MRW<DK0WUE<DB0RES<ON0AR<N9ZZK<CX2SA<GB7YFS<GB7SYP<GB7ESX<
GB7NNA
Sent: 060412/2257z 03782@GB7NNA.#31.GBR.EU $:AC4309G0FTD [Witham, Esx]NNA V3.1
I've just been messing about with my "trolley mobile" antenna on the LF
bands and trying in particular to get 160m to tune up reliably.
In effect it's just a 7.5m vertical and a 15m throw out wire radial on the
ground.
At 160m the values of the atu components start to run out of steam when
trying to cope with large reactive impedances down there.
My trolly vertical is typically 1-j1300ê , a bit much for my little
LDG Z100 atu to cope with.
So I inserted a 4:1 balun at the feedpoint to transform this high reactance
to something more manageable and voila!
Nice and easy to match now.
With the trolley system stood in the back yard my first QSO was with an
OK2 station and I was running a genuine 30w of CW. The QSO was easy, so
it proved the antenna was radiating.
I didn't make any other QSO's as it was getting a bit chilly, so I went QRT.
So the moral of the story is - well that should be obvious by now ;-)
.-"""""-.
/ 73's de \
.-. | _ _ | .-.
(_. '._ | |_\ /_| | _.' ._)
-._'-.(_ A _).-'_.-'
'-._| _____ |_.-'
_.-'_\`"""""`/_'-._
.-.-'_.-' `-----' '-._'-.-.
(,_.'` `'._,)
Colonel Andy
Supreme Commander of the Trolley Platoon
And The Laughter Corps
www.southgatearc.org/articles/g0ftd/shopping_trolley_wally.htm
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