A Six Band tower switching system

摘要

When I first moved to McKinney in 2000 and had the luxury of a tower, thoughts started on how to get on as many bands as microwave possible, (902 through 10G). Initial thoughts were to run a feed to each antenna (6 hardlines). However if running a MHP there was a risk of transmitting up the preamp so separate RX and TX lines were needed (12 hardlines + preamp power cables!) The weight of those cables hanging off the tower would be much too high. Thoughts then turned to switching all the TX signals onto one hardline and switching all the RX signals onto another hardline. This would require a pair of 1P6T RF relays on the tower, but the weight hanging off the tower would be lower. At this point 1 came across some SMA 1P6T relays (for RX) and some N type 1P6T relays with auxiliary switching contacts for which I paid $80 total, so construction could begin. The circuit diagram, Figure 1 shows how it was done with an example of my 2 band configurations; masthead preamp and masthead transverter. Note the Transverters do not need a PTT signal, TX/RX switching is done by sending 9V on TX up the IF cable. Not shown are the diodes across the relay coils.