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Author Topic: W8AMZ G5RV and Icom 746  (Read 1037 times)

Posts: 211

« on: July 29, 2012, 01:46:51 PM »

Hello -
 I was wondering if anyone has had any experience with using an Icom 746 and its antenna tuner with the W8AMZ version of the G5RV? the W8AMZ version claims to work without a tuner on 40 and most of the bands above but it requires a tuner on 80, 60 and 15. I'm curious if the internal tuner on that rig is capable of matching it well. Thanks.

Bruce  K6RQR


Posts: 3616


« Reply #1 on: July 30, 2012, 03:03:20 AM »

I'm curious if the internal tuner on that rig is capable of matching it well.

This is a ZS6BKW style antenna. When it says it operates on a band without a tuner, it doesn't necessarily mean the entire band. The frequencies where it works without a tuner may not always be the frequencies you want to be on. For instance, EZNEC sez the antenna has the lowest SWR around 29 MHz which is indeed in the 10m band but on 28.4 MHz, where most of the action is, the SWR is 7:1 according to EZNEC.

The autotuner in the IC-746 is spec'ed to operate with SWRs up to 3:1 so don't expect it to achieve a match on 28.4 MHz. It might or might not. Also, the SWR will change with height above ground and in the inverted-V configuration, to name just a couple of things that can change the SWR. I modeled it horizontal at 40' high.

It is hard to predict whether you would be satisfied with that combination or not. A ZS6BKW cannot be recommended for 80m, 30m, 15m, and 6m operation so beware  the "works with tuner" marketing hype. It certainly is unlikely to work with the IC-746 internal autotuner on those bands. Even with a wide-range external tuner, the SWR on the coax between the tuner and antenna will be worrisome on those 4 bands.

73, Cecil,
The purpose of an antenna tuner is to increase the current through the radiation resistance at the antenna to the maximum available magnitude resulting in a radiated power of I2(RRAD) from the antenna.

Posts: 78

« Reply #2 on: July 30, 2012, 04:52:37 AM »

While i have not used his g5 I have purchased a couple antennas from him, 160 sloper and 40M inverted "T" vertical and they are well made, actually the construction is impressive!
I am very satisfied with his antennas and plan on purchasing more from him, if you buy the G5 or any G5 for that matter just bear in mind that it is a comprimise antenna, I myself use one (not his) flat hung at 55' set n/s and have excellent results the internal matching unit on my 756 proII and 746 pro matches just fine on the freqs it is rated for.

Either way a low power manual or auto matching unit is not very expensive...

Good Luck!
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