I have always found the the OCF antennas require a sufficient amount of feedline to mask the weird impedances it has. I have successfully used 135 foot 33% offset fed 4:1 balun with W1JR choke and >100 feet of coax necessary. I tried to use 22 feet and it was a total loss. All with <100 watts of course like Jim suggests. The added length does not add enough loss to account for the change.
Mel, K6KBE On Saturday, July 5, 2014 9:50 AM, Dave <[email protected]> wrote: I tried a 40M OCFD for a while. I gave up on it and went back to a centre fed dipole instead. Even on 40M it didn't seem very good and I was plagued with RF getting into PCs and them shutting down or periferals stopping working. Plus, despite the hype, it didn't really seem to work well on other bands. The Antenna analyser was very dismissive, showing resonances outside of the Amateur bands and, on some that it was supposed to work on, no sign of any resonance at all. Dave (G0DJA) ----- Original Message ----- From: "Jim Brown" <[email protected]> To: <[email protected]> Sent: Saturday, July 05, 2014 2:24 PM Subject: Re: [Elecraft] A Good Antenna Length? > On 7/5/2014 2:05 AM, David Cutter wrote: >> You might consider an off-centre-fed dipole with appropriate balun and >> choke. > > Not if you're going to run power. An off center fed antenna generates high > common mode voltage, which will fry even the best choke when running > power. I wouldn't consider such an antenna at greater than 100W. > > 73, Jim K9YC > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[email protected] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [email protected] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [email protected] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [email protected]
