[TowerTalk] TH7 phasing-line impedance

Chris Tran GM3WOJ gm3woj@talk21.com
Fri, 25 Feb 2000 18:45:36 -0000

Hello all

I'm converting an old TH7 to a 10m monobander, but would like
to retain the original 'phasing tubes' and 'beta match' if poss.
(just to save time, and use the original R-DE to F-DE spacing,
but the 70" long 'beta match' looks far too big for 28MHz

Can anyone tell me what the impedance of the existing phasing-lines
on 28MHz was intended to be - I'm guessing 150-200 ohms ?

Maybe I should just discard one driven element and make a hairpin
match for the other, but I'm hoping to widen the useful bandwidth by 
retaining the 2 driven elements (I'm a 6m fan and need to go
on 28885 at times!)

Thanks for any help

GM3WOJ/GM7V    gm3woj@talk21.com

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