[Elecraft] SWR Readings:Differences

[Fred Townsend]

Hello Mark:
Question? What is the SWR of a mile long piece of coax if it is unterminated.
Answer 1:1. That is because a long length coax will act as a matching transformer. Actually it doesn't have to be too long as you found out. If reading is not better in the shack something is wrong.

Mark what you are seeing is entirely normal. If you want to measure the antenna impedance from the shack you should use something like Time Domain Reflectometer.

73
Fred 

-----Original Message-----
>From: pastormg2 at verizon.net
>Sent: Sep 2, 2014 5:06 PM
>To: elecraft at mailman.qth.net
>Subject: [Elecraft] SWR Readings:Differences
>
>Good Evening,
>This is Mark Griffin, KB3Z and I have some questions regarding the SWR readings I get at my tower versus what I get on my K3. I will give the SWR readings that I got at my tower for a 40 meter rotatable dipole at 55 feet.
>
>Tower:
>
>7000  2.2
>7025  1.8
>7050  1.5
>7075  1.3
>7100  1.0
>7125  1.1
>7150  1.3
>7175  1.6
>7200  2.0
>7225  2.2
>
>K3 Readings:
>
>7000  3.5
>
>7025  3.2
>
>7050  2.9
>
>7075  2.6
>
>7100  2.4
>
>7125  2.3
>
>7150  2.4
>
>7175  2.5
>
>7200  2.6
>7225  2.9
>
>What would cause such a big difference. The cable run from my antenna switch on the tower to my K3 is only an additional 75 feet. I am using RG-213 cable. Is there anyway that I can test the SWR reading that my K3 is giving me?
>
>Mark Griffin, KB3Z
>
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