http://elecraft.85.s1.nabble.com/OT-Need-Antenna-Tuning-Help-tp7327188p7327406.html
Well, crud - my fat fingers messed up the original post. That reading at 3.654 should have been R=50, X=1, SWR=1.0. I'll take the MFJ out to the antenna base and see what I get.
> On 2/28/2012 2:22 PM, Jim Bennett wrote:
>
>>
>> I get TWO SWR
>> nulls. Yes, two. One is at 3.461 and has R=35, X-0, and SWR of 1.3.
>> The second null is at 3.654, R=0, X=1, SWR=1.0.
>
> You have something seriously wrong, 0+j1 ohms is a short circuit, or
> extremely close to one. I'm sure the SWR reading at that point is
> bogus, the MFJ was not designed to operate into a short circuit. In
> fact, the apparent "short circuit" could be bogus, I've gotten some very
> improbable results a few times with my MFJ.
>
> I'd suggest:
>
> 1. Take your MFJ259 out to the feedpoint of the antenna and see what
> you get.
>
> 2. Put a dummy load at the antenna end of your coax run and measure the
> impedance at the shack end. It should be 50+j0 ohms everywhere [within
> reason]
>
> 3. Check the SWR with your K3 with the tuner in bypass at 3501 and up
> the band a few places and draw a graph of the readings. Keep the power
> down, you can't really hurt the K3, it'll quit making RF if it gets
> really annoyed. If the null at 3461 is really the resonant point of
> your antenna, you should see the SWR climbing rapidly as you go up the band.
>
> When really weird things happen in conflict with known physics, it's
> almost always a simple error in the system or measurement configuration.
> I'd look carefully at the wiring. Let us all know what you find, I'd
> like to write it into my notebook for future ref.
>
> 73,
>
> Fred K6DGW
> - Northern California Contest Club
> - CU in the 2012 Cal QSO Party 6-7 Oct 2012
> - www.cqp.org
>
>
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