I have been working on antennas today and have a puzzle. I am finding that the K3 SWR indications are unbelievable generous.
With my 40M inverted V fed with RG8X (50 ohm) coax I see that the K3 seems generous in the SWR indication on tune with ATU bypassed. I have noticed a slight change in SWR with K3 power setting so the following was taken with K3 tune power set to 100 watts. If I set it to 10 watts the discrepancy is greater... SWR SWR SWR Freq. K3 VA1 Daiwa 7.00 MHz 1.3 1.92 2.0 7.05 MHz 1.2 1.92 1.9 7.1 MHz 1.2 1.98 1.95 7.15 MHz 1.3 2.26 2.1 7.2 MHz 1.9 2.60 2.3 7.25 MHz 1.5 2.88 2.6 7.3 MHz 1.6 3.32 2.7 The Daiwa is the CN-101L cross needle meter. The VA1 is the Autek Rx Vector antenna analyzer. The VA1 does not have a tuned input so it is possible that it can be fooled by local broadcast stations. I don't suspect this issue here as there aren't any close by broadcast stations that I am aware of. The Daiwa and the VA1 tend to agree pretty well anyway. The K3 measurements are the outliers. This antenna on a "Tenna Dipper" shows minimal SWR at 7.040 MHz, just where I tuned it a few years ago. The LED does not extinguish indicating higher than 1:1 SWR at the minimum. If you look at the numbers, I guess I don't believe the K3, Do you think my antenna is below 1.6 to 1 across the entire 40M band? So now on to 20M dipole fed with RG58 (50 Ohm Coax)... The Tenna Dipper fully extinguishes at 13.805 MHz indicating that my antenna is bit too long but is close to 1:1 at that frequency. Freq K3 VA1 Daiwa 13.81 -- 1.12 -- 14.0 MHz 1.1 1.24 1.31 14.1 MHz 1.1 1.30 1.70 14.2 MHz 1.1 1.55 1.85 14.3 MHz 1.2 1.69 1.85 RG58 may have some losses on this band so perhaps all of the SWR indications are generous, some more than others. The dipole is a low one and probably isn't 72 ohms at the feed point. Mike Scott - AE6WA Tarzana, CA (DM04 / near LA) K3-100 #508/ KX1 #1311 _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com