Bernie Doran wrote: > Hi Larry: what a dinosaur!!! you might even be older that I am. I > have not heard an 80 AM station since 1950s. but that sure qualifies > for a few feet. I wonder if anyone ever thought there was something > wrong with their xmtr. bet you could tell them that you are setting it > for side band the way TV does!! Bernie Hi Bernie!
Yep, vestigial sideband. Nope, you're older, but I probably have older gear! The first time I got a report like that I didn't think much of it. The second time it was from I a guy whose technical expertise I knew and trusted, so I took it as accurate. At first I couldn't think what might make a classic plate-modulated class C transmitter have asymmetric sidebands, and wasn't coming up with anything for a satisfying explanation (mobile transmitter was/is an Elmac A-54H, class C 807 modulated by pair of 5881s). Then I though about how sharp the antenna tuned, and I came to the conclusion the antenna was acting as a sideband filter - albeit not a terribly effective one (assuming you wanted SSB - but who would want that? ;-)) 73 and hope to talk to you on the air again this fall/winter, -Larry/NE1S > ----- Original Message ----- From: "Larry Szendrei" <[email protected]> > To: "Discussion of AM Radio in the Amateur Service" > <[email protected]> > Sent: Tuesday, June 22, 2010 12:19 PM > Subject: Re: [AMRadio] Antennas > > >>> There have been some interesting cases with short loaded antennas >>> in the BC band, the bandwidth has occasionally been so narrow that >>> the AM >>> sidebands become attenuated! Not going to see that effect in the >>> amateur >>> bands unless someone is running an antenna only a few feet long!! >> >> Correct. This has been observed on my 75M AM mobile signal, with reports >> of one sideband being attenuated relative to the other. Antenna is a >> Webster bandpanner ("a few feet long"). >> >> 73, >> -Larry/NE1S > ______________________________________________________________ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/[email protected]/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Post: [email protected] To unsubscribe, send an email to [email protected] with the word unsubscribe in the message body. This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
