Geoff Try putting a 50 ohm dummy load in line and see if the K3 and your ext. meters read the same swr. This will take reactance and inbalance out of the picture.
Steve Ellington [email protected] ----- Original Message ----- From: "Geoffrey Downs" <[email protected]> To: <[email protected]> Sent: Monday, May 04, 2009 10:14 AM Subject: Re: [Elecraft] K3 - SWR Indication > ----- Original Message ----- > > From: "Steve Ellington" <[email protected]> > > >>It appears that your coax does not exactly match the impedance of your >>dipole (It rarely does).... > ------------------------------------- > > Thank you Steve for your comments. I fully accept about a probable > mismatch > between dipole and coax (and of course the performance of the antenna > remains to be seen), also that there are many factors affecting SWR and > that > sampling at different points along the coax will produce different results > if there is reactance in the load. In this case the antenna feeder was > connected to the LP100A about 2.5 inches down the line from the ANT 1 > socket. To my mind that seems a short length to account for an SWR > difference at 7 Mhz as big as 1.2:1 (K3) vs 2.0:1 (LP100A and MFJ 259B). > We > all need to know what sort of load the rig or the amplifier is looking > into > and a discrepancy like that is unsettling. > > All three measuring devices see no reactance and 1.0:1 at 7.145 MHz. What > seems to happen is that as one moves up or down in frequency from that > point > (and the load gains reactance) the K3 indication remains significantly > lower than than other two. I doubt if 2.5 inches of coax would account for > the difference and the MFJ259B, which agrees with the LP100A, > connects to the antenna feeder at exactly the same point as the K3's > ANT 1 socket so there is not even that extra 2.5 inches. > > It leads me to think that maybe my K3 is not measuring SWR as well as it > should either due to a fault in my particular one or to the way it is set > up > to work. > > 73 to all > > Geoff > G3UCK > > > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[email protected] > > 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:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
