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I agree with Pete: One of the few scientifically credible beam camparison reports I know of is: Overbeck, W. "Quads vs Yagis", Ham Radio, May 1979, pp.12-21. Generally the tribanders are pathetic with respect to bandwidth and forward gain. Adding lossy elements improves the F/B but does little for forward gain, hence the multielement tribanders showed little forward gain advantage over the two element tribander used as the comparison antenna. There was no comparison with a full size two element yagi, but this would have been expected to perform better or as well as any of the tribanders tested with respect to forward gain. Two element quad looked good. The larger monoband yagis tested blew away even the largest tribanders. Modelling exercises with realistic figures for trap losses agree with the above. If F/B is important at a given location then overall system performance may be better with a multielement tribander and upping the transmit power (mind you don't burn the traps, tho!). At this QTH where F/B not an issue, changing from TH5 to the modest 3C-S gave immediate audible improvement, as Pete says. 73 Barry Kirkwood PhD ZL1DD Signal Hill Homestay B&B 66 Cory Road Palm Beach Waiheke Island 1240 NEW ZEALAND www.waiheke.co.nz/signal.htm ----- Original Message ----- From: Pete Smith <n4zr@contesting.com> To: <force12talk@qth.com> Sent: Sunday, 09 July, 2000 1:26 PM Subject: Re: [Force 12 Talk] C3 over Cushcraft A4 > At 09:20 PM 7/8/00 -0400, wa4dou@juno.com wrote: > >Hi Len, > > I doubt that the C3 represents more than a slight improvement over what > >you already have. I would recommend the C19XR as the logical step up for > >you. I have the C3SS and i'm happy with it. If i had more rotator(i only > >have a Yaesu 450A) i'd opt for a C19XR myself. > > I just gotta disagree with Roy here. In the N0AX/K7LXC tribander tests, > the C-3 rated above all the small tribanders tested and all but 2 of the > big ones. While the test protocol isn't perfect it's about the only > concrete info we have, and it pretty clearly demonstrates that the C-3 will > wax any trapped tribander except maybe the KT-34XA. Not to revive an old > argument, but I bet you can hear the improvement over an A4, even in casual > operation. > > That being said, if you can handle the wind area, weight and cost of the > C19, why not... it is clearly better yet! A 2-element yagi (or 3 of them, > like the C-3), will not have either the gain or (particularly) the F/B > ratio of an antenna with 3 or more elements per band, with a comparable > element spacing (longer effective boom length). > > 73, Pete Smith N4ZR > > The World Contest Station Database > is back up and running at > http://www.qsl.net/n4zr > > > > > -------------------------------------------- > Force12Talk mailing list provided as a service by Force 12 Antennas, Inc. > Force 12 Web site: http://www.qth.com/force12 > > Submissions: send to Force12Talk@qth.com > To unsubscribe: send a blank e-mail to Force12Talk-leave@qth.com > Force12Talk Message Archive: http://www.qth.com/force12/list/force12talk > For problems with the list, contact force12@qth.com > > > -------------------------------------------- Force12Talk mailing list provided as a service by Force 12 Antennas, Inc. Force 12 Web site: http://www.qth.com/force12 Submissions: send to Force12Talk@qth.com To unsubscribe: send a blank e-mail to Force12Talk-leave@qth.com Force12Talk Message Archive: http://www.qth.com/force12/list/force12talk For problems with the list, contact force12@qth.com |
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