[Elecraft] 75 ohm coax

[donovanf at starpower.net]

Hi Tony, 


Reasonable coaxial cable loss isn't an issue on the low bands unless 
you're using an inefficient receiving antenna (e.g. small loop, BOG, or 
high impedance short verticals). Most inefficient receiving antennas 
use a remotely powered preamp at -- or very near -- the feed point so 
even in those cases feed line loss isn't an issue on the low bands 


73 
Frank 
W3LPL 

----- Original Message -----

From: "N2TK via Elecraft" <elecraft at mailman.qth.net> 
To: "Frederick Dwight" <kl7cw at mtaonline.net>, elecraft at mailman.qth.net 
Sent: Friday, April 3, 2020 5:31:45 PM 
Subject: Re: [Elecraft] 75 ohm coax 

I have been using Commscope F660BEF for years for both receive lines and 
transmit coax for my 80M 4-sq using F-connectors. The other year I had a 
100' piece of RG6 that had a solid copper center conductor and a copper 
braid. Compared that to the F660BEF on 1.8 and 3.5 for loss at 100'. I did 
not see any difference in power loss. I guess the F660BEF has enough copper 
plate to keep losses low on the low bands. Or maybe I just had a bad piece 
of copper RG6? 
N2TK, Tony 

-----Original Message----- 
From: elecraft-bounces at mailman.qth.net <elecraft-bounces at mailman.qth.net> On 
Behalf Of Frederick Dwight 
Sent: Friday, April 3, 2020 2:09 AM 
To: elecraft at mailman.qth.net 
Subject: [Elecraft] 75 ohm coax 

If your 75 ohm coax has a steel/copper coated center conductor, be sure to 
test it for loss on the lowest frequency band you will use. I experimented 
with a steel core 160 meter antenna and found it had some additional loss 
and probably due to the inductance it could be shorter for resonance (10 % 
perhaps ??) so I abandoned the idea. Never noticed the effect on higher 
frequencies. 

Sent from Mail for Windows 10 

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