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[TowerTalk] RE: [Antennas] coax 'sweet lenght'

To: "'FireBrick'" <>,"'TowerTalk List'" <>,"'Antenna List'" <>
Subject: [TowerTalk] RE: [Antennas] coax 'sweet lenght'
From: "Chris Boone" <>
Date: Sun, 10 Oct 2004 11:03:34 -0500
List-post: <>
ANY feedline repeats the Load Z (Impedance) every
1/2wavelength..remember that must take into account the velocity factor
of the feedline...for normal coax its about 66% so 0.66 x 468/freq in
MHZ = length of 1/2 wl coax at that freq...the only thing about this is
you can use ANY feedline bewteen radio and antenna as long as its 1/2 wl
and the radio will match the antenna (if the antenna is 50ohm +0j
already)....SWR at the radio will be accurate.....if the antenna is NOT
50ohms or has reactance, the feedline will always cause a WRONG SWR
reading at the xmtr unless it is a 1/2 wl (in coax)..
Hope that helps.


> -----Original Message-----
> From: 
> [] On Behalf Of FireBrick
> Sent: Sunday, October 10, 2004 8:49 AM
> To: TowerTalk List; Antenna List
> Subject: [Antennas] coax 'sweet lenght'
> I remember discussion that there was a 'sweet length' for 
> rg8, rg13 coax lengths. The length was a multiple that gave 
> the best match, etc. 
> Or is this the Ham version of 'urban legend'???
> But senility won't allow me to remember what it was or where 
> I stored this info.


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