Because of a lack of shielding in most RC transmitters you don't really know how long the antenna really is. The "real" length includes the base that goes into the transmitter, sometimes all the way to the bottom, and also the wire from the RF deck to the antenna. The only way to tune the antenna length is to use a SWR (standing wave reflection) meter, which requires rewiring of the transmitter. Since all current transmitters have more than enough transmitted power to control the plane within sight there really isn't a reason to go to all this effort.
Anker -----Original Message----- From: Bryan Becker [mailto:[EMAIL PROTECTED] Sent: Friday, August 13, 2004 3:42 PM To: [EMAIL PROTECTED] Subject: RE: [RCSE] Antenna Info Simon, Is there an easy way to tune your antenna length, once you have installed your RX in your model? --Bryan -----Original Message----- From: Simon Van Leeuwen [mailto:[EMAIL PROTECTED] Sent: Friday, August 13, 2004 1:34 PM To: Jared Cc: [EMAIL PROTECTED] Subject: RE: [RCSE] Antenna Info Just to be clear here, longer is not better. Take 72MHZ, a frequency that is resonant at ~4 meters. This equals lambda, therefore 1/4lambda is ~1 meter. In order for an antenna to be resonant, it must be close to these values in length. changes in length either way (longer or shroter) produce the same losses. Quoting Jared <[EMAIL PROTECTED]>: > Thanks for everyone's replies! I think I'm going to do a little more > digging about building antennas before I start on this. > > Bill - the only way that I could see to make a longer antenna less effective > than a shorter one is to have it tuned out of the wavelength...or to have a > unidirectional antenna pointed the wrong way ;) But I do agree that in > general longer = better. > > Again thanks to everyone for their replies! > > Jared > > -----Original Message----- > From: Bill Swingle [mailto:[EMAIL PROTECTED] > Sent: Friday, August 13, 2004 1:50 PM > To: Albert E. Wedworth; Jared; [EMAIL PROTECTED] > Cc: [EMAIL PROTECTED] > Subject: Re: [RCSE] Antenna Info > > >>I have always had great sucess with R/C Direct products.. > > > Please understand; I was not commenting on R/C Direct products specifically. > > But, in my experience. Most any antenna designed to be shorter than the > factory monopole will Decrease signal. The R/C site agrees with this and > claims a minimum range reduction. No surprise here. > > I was merely trying to headoff the folks who have in the past touted a few > antennas that are better than stock. It was just sales baloney and I'd hate > for folks to be misled again. Smaller equals worser; doesn't have to be that > way. But, that's just how it tends to be. I'd love to find an exception. > > Bill Swingle > > > > RCSE-List facilities provided by Model Airplane News. Send "subscribe" and > "unsubscribe" requests to [EMAIL PROTECTED] Please note that > subscribe and unsubscribe messages must be sent in text only format with > MIME turned off. > > > RCSE-List facilities provided by Model Airplane News. Send "subscribe" and > "unsubscribe" requests to [EMAIL PROTECTED] Please note that > subscribe and unsubscribe messages must be sent in text only format with MIME > turned off. > Radius Systems Cogito Ergo Zoom RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off.
