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On Feb 23, 12:40 am, "Sal M. Onella"
wrote: wrote in message ups.com... On Feb 22, 12:16 am, "Sal M. Onella" wrote: It was a bust. :-( They can be quirky..And the decoupling is pretty critical. I always preferred a base fed half wave for those reasons. You still need to decouple for best performance, but there are no "coax in the way" issues, etc.. I use a simple "gamma loop" feed. IE: single turn coil, and a cap if needed. Sometimes you don't need the cap, but if you do, 30-50 pf is about the usual value for 10m. I make those from a short length of coax.. I'm basically copying the feed system of the usual cushcraft ringos.. BTW, cushcraft sells a 10m ringo if one doesn't want to build one, or have the tubing. I will try decoupling and also try that feed. I have several commercial antennas but I tend toward building them myelf. I learned the hard way about the three types of copper pipe, K, L, & M. Until I got home and hit google.com, I didn't know to shop for the more economical Type M and paid premium $$$ for Type L. I don't want to think what Type K would have cost. "Sal"- Hide quoted text - - Show quoted text - Sal, I would like to know how it works with the PVC as I have tried it on exactly this type of antenna and it worked horribly. Apparently the PVC I was using has some really lousy dielectric qualities, This stuff would melt in a microwave while other PVC pipes do not.. I understand that all PVC is not created equally and that some may be OK. To get mine to work I used larger pipe, smaller coax, and a different insulating material but my original was identical to your first attempt. Unfortunately for me I made all the changes at once and really dont know which fixed the problem except that the PVC was an issue. I am very interested in finding whether or not just adding the choke fixed the problem because this is also something I forgot to do on my intial attempt. Second attempt had one of those chokes from "Wireman" made of a length of coax and ferrite beads. One thing that concerned me even after the antenna was working is the the SWR appeared to be a little too good. It was 1.2:1 in the middle of 10 meters and never got ave 1.7:1 even at the band edges. I thought that this is a little too good to be true.. Jimmie |
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