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Remote Antenna Relay Selector

 

 

The circuit above is what I propose to use for remote relay antenna selection.  After discussion with Julius D. Jones, the owner of W2IHY Technologies, who kindly related how he achieved 70 dB isolation through the use of two relays instead of a single relay that only provides 40 db of isolation, I have decided to construct a remote coax selector box myself.

I have designed a circuit that uses a single 3-pole DT relay that should provide the requisite isolation and protection from high voltage flash-over by placing two open contacts in the path of the unused portion of the circuit. (Drawing above) This permits me to incorporate metal-oxide varistors (MOVs), and other surge protection, on the relay control lines to mitigate potentially harmful surge currents that may be induced into them, and place capacitors and 1KV PIV diodes reverse biased across the relay coils to dampen any inductive spikes that may be generated upon coil de-energisation.

Constructing a remote relay coax selector also permits me to incorporate a weatherproof enclosure, and provides the pride and satisfaction afforded by designing and constructing.

Below are some photographs taken during the construction of the remote antenna relay selector system.

 
                 
         
                 
         
                 
         
                 
         
                 

The Alpha Digital Antenna Selector (DAS) controls the remote antenna selection relays.  The Alpha 78A linear amplifier automatically tunes to the transceiver VFO transmit frequency, and selects the antenna that has been previously programmed for that frequency band.  The DAS may also be controlled directly by TRX-Manager either locally or remotely.

 
     

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Hits: [an error occurred while processing this directive] Date of last edit: January 21, 2013 05:50:40 -0800
Copyright: L. Dighera, 2012; All Rights Reserved: LDighera@att.net