[TowerTalk] Matching 75 ohm hardline for 3 bands

Pete Smith n4zr@contesting.com
Sat, 31 Mar 2001 12:59:06 -0500


At 09:22 AM 3/31/01 -0800, Jim Berry wrote:
>I had the same question once. The SWR change is not great enough to
>warrant any stubs or anything.  Just do not mix 50 ohm and 75 ohm
>coax.  Also remember that your SWR meters are probably set up to read
>50 ohm line.  They will not really be accurate on the 75 ohm stuff.
>I use the big hardline to the smaller flexible stuff like they use to
>feed your TV.  I have gone so far as to change all my stuff to the F
>connectors.

In my installation, my single run of 75-ohm hardine is connected on either
end to lengths of RG-213, and all my in-shack jumpers are 50-ohm.  I think
it makes sense, as Tom says, to not have more than one length of 75-ohm in
a run, but my setup certainly works OK(see my previous message).  

I would be very skeptical of the F connectors, particularly for significent
amateur power.  The very limited contact area of the center conductors
strikes me as a problem just waiting to happen.

73, Pete N4ZR
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