Sam, Just to give you a ballpark estimate, I used CommShop for Windows to generate a solution for a 50 watt transmitter that is separated by 600 kHz from a receiver with 0.25 uV sensitivity in the 2m Amateur band. CommShop reported that a minimum of 90.14 dB of isolation is required, which can be met with a vertical antenna separation of 240 feet- assuming that the antennas are identical and are exactly in line with each other vertically. The required horizontal separation to achieve the same isolation is about five miles, which is obviously impractical without a link radio. If you use a transmitter with greater power, or use a receiver with greater sensitivity, the required isolation and the separation will increase.
It makes no difference if your machine is used once a year or continuously; the isolation requirements are firm. 73, Eric Lemmon WB6FLY -----Original Message----- From: [email protected] [mailto:[EMAIL PROTECTED] On Behalf Of Sam Sent: Friday, March 23, 2007 9:27 AM To: [email protected] Subject: [Repeater-Builder] TX & RC antenna seperation What would be the guidelines to use for antenna separation on a 2 meter machine w/o a duplexer. Horizontal and vertical, this will be a limited use machine, so there will not be a lot of traffic. Sam KE5MID
