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Re: improvement of a C-3 over an A-4 Yes, the C-3 is an impressive step up compared to a trapped antenna such as the one on question. Most everyone can come to that conclusion by going through a few logical steps: a) the trapped tribander has minimal elements and fixed element positions, so the location of each element that contains traps is a compromise b) the feedpoint of the trapped antenna is 50 ohms on all 3 bands. Anyone who has done computer modeling can tell you that moving a Yagi up to 50 ohms requires some effort and to have all 3, with compromised element positions is a real clue that there is loss in the antenna (remember how well a dummy load produces a 50 ohm load.) One of the 3 bands can be set for 50 ohms (such as 10 mtrs), but the others are moved up to 50 ohms using loss. This was first noted to me many years ago by Brian, K6STI, who wrote all that fine modeling software (AO/YO). c) having measured the trapped antenna in question, as well as many others, is how we determined the minimum gain level for a higher-performing antenna. It was obvious that a 2-element Yagi would easily surpass the trapped antennas and the result is the C-3 and subsequent variants of the basic design. The measurements were made by an outside consultant and measured several wavelengths and at 12-15 degrees in the main lobe of the antenna (not at zero degrees). A full size dipole was substituted before and after each test, at the same height, same location, same coax. Each test was performed more than once and the spectrum analyzer was at 2dB per division (consultant showed us the calibration information). d) the comments from those who have changed to the C-3, or any of the C-series, from trapped antennas are consistent - many have said that they no longer need to use their amplifier. Have dozens of written letters and e-mails about this. Sure, these are anecdotal remarks; however, they are always the same, over years, in all sorts of locations and environments and track with other test data. Sometimes, people think that we build non-trapped antennas just to be different. The fact is that we performed the trapped antenna testing to determine how to build a better antenna. If a higher performance Yagi could be done using traps, that was fine. If it meant using an LPDA design, that would be fine, too. These technologies were already available and time to market would be very quick. However, the multi-monoband Yagi was the right answer and it took years of effort to perfect it: the overlay and forward stagger techniques, plus more years to have the lossless open sleeve feed system patented. If you move up to the C-3, you will notice how alive the band sounds. If you like 10 mtrs, use the C-3E. I just put back up C-3 #1 (1993), which is also C-3E #1 (1997). It has been a long term test antenna, using half of the rivets as normal and only 1 in the tips. No mechanical problems at all and the PVC is also fine, even after baking in the 100 degree and higher sun here for the past 2+ years. As a standard 80 mph design, it has survived 5 storms of >100 mph. It has been taken apart several times, moved and re-installed with no difficulties at all. It was on the air in the IARU/WRTC this past weekend by K2KW who operated part-time, mainly looking for WRTC stations. Don't have the exact figures, but I believe he worked 51 individual WRTC stations and more than 110 total band/mode WRTC stations. I never hesitate to recommend it, or a stack of them, to a serious contester. The C-19XR does have more gain and excellent F/B; however, it is also more windload and 20+ pounds heavier. The C-19XR is aimed at only 20-15-10. The C-3 also has some gain on 17 & 12, so it is more versatile, plus you can add 40 mtrs to it. Finally, you should review the testing done last year by Ward Silver and Steve Morris. These two gentlemen tested most of the contemporary tribanders and the results indicate some of the trapped designs have little or no gain over a dipole. You can obtain this report from Champion Radio Products at 888 833 3104 I use both the C3E and the C19XR at my home station, therefore I'm very familiar with these two antennas. Furthermore, six years ago, I conducted a three month test with a C3 on one tower and a new A4S on my other tower. Compiled the data for six weeks and then reversed the two antennas. The final results using A/B type switching were overwhelmingly in favor of the C3 on all bands, seeing vast differences in favor of the C3. Finally I switched out the A4S with a rotating 20 meter dipole and found that the differences between the C3 and the A4S were repeated using the dipole! 73 Natan W6XR Force 12 East Ithaca, NY FN12sk force12@qth.com ----- Original Message ----- From: <leon0@attglobal.net> To: <force12talk@qth.com> Sent: Saturday, July 08, 2000 7:06 PM Subject: [Force 12 Talk] C3 over Cushcraft A4 > Hello I want to replace a Cushcraft A4 with the C3 or the C19XR > > was wondering if the C3 has that much more gain over the A4 also would > the > > C19XR be worth it over the C3? > > Thanks for reading and any info. > > Len WA7ZXZ > > > > -------------------------------------------- > 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. 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