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 Tuesday, Feb 28, 2012, at Tuesday, 3:43 PM, Fred Jensen wrote: > 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 > > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
