Thank you for your response. The problem is that the repeater is located on top of a building and the tower on that building is only about 20 feet tall. We can move the two antennas apart horizontally, but only 20 feet vertically. Duplexers are way too expensive and hard to find for the 200 Mhz band. We are running about 20 watts and the frequency separation is 1.6 mhz. Sometimes a week signal comes in and sometimes the transceiver is desensitizing the receiver and covers it up. Any suggestions? Thanks Chris In a message dated 8/30/2010 8:36:53 P.M. Eastern Daylight Time, wb6...@verizon.net writes:
Chris, You do not have to use a duplexer, but it makes building a repeater SO much easier! Keep in mind that "antenna separation" usually means vertical separation, not horizontal separation. Moreover, the same isolation provided by 1000 feet of horizontal separation might be provided by 10 feet of vertical separation. The amount of isolation you need is based generally on the transmit power, frequency separation between TX and RX, and the sensitivity of the receiver. The receiver bandwidth and antenna types also play a factor. 73, Eric Lemmon WB6FLY -----Original Message----- From: _repeater-buil...@yahoogroups.com_ (mailto:Repeater-Builder@yahoogroups.com) [mailto:_repeater-buil...@yahoogroups.com_ (mailto:Repeater-Builder@yahoogroups.com) ] On Behalf Of Mackey Sent: Monday, August 30, 2010 4:44 PM To: _repeater-buil...@yahoogroups.com_ (mailto:Repeater-Builder@yahoogroups.com) Subject: [Repeater-Builder] Duplexers Our club was recently given a 220 repeater. We have two seperate antennas. We do not have a duplexer. My question is do we have to have a duplexer? How can we keep the transmitter from desensitizing the receiver? The antennas are apart but can be moved farther. Thanks Chris Kg4bek
