[Elecraft] A Good Antenna Length?

[Wayne Burdick]

Jim,

Try 102 feet (or so) for each leg of a dipole fed with twinlead or open-wire line. This is not a close multiple of a half-wave on any band from 160-6 meters, so it stands a chance of providing a reasonable match on all bands. 

If the internal tuners can't find a match on one or two bands, adjust the length of one or both sides by a couple of feet experimentally. It'll be slightly imbalanced if it ends up off-center-fed, but this won't have much practical impact.

At my QTH I use a 4:1 balun (Elecraft BL2) right at the radio to feed this antenna. The BL2 also has a 4:1/1:1 switch. I use the 4:1 setting for all but one band, where the 1:1 setting makes it easier on the ATU. Note that if you don't get to a low SWR when you first tap ATU TUNE, tap again within 5 seconds and the tuner will try more LC combinations. This will nearly always provide a 2:1 or better match unless the antenna presents a very high impedance. 

The KXAT3 will match a wider range than the KXAT100. For safety reasons, our QRO ATUs put limits on the SWR they will try to match.

Use a good ground at the station. If in your installation you experience any RFI at higher power, drop back to a lower level.

73,
Wayne
N6KR


On Jul 4, 2014, at 2:21 PM, Jim GM <jim.gmforum at gmail.com> wrote:

> What antenna lengths are you using on 160M with your KX3 or  KXPA100
> internal tuner? What is best for 160-6 meters? I like making my own
> antennas with wire.
> 
> I usually have to give up one band or another cause it just would not tune
> up on a certain band.
> 
> I have tried to stay with in these guide lines.
> 
> -- 
> Jim K9TF
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