Topband: 4 Direction Reversible Beverages Remote Control via Coax Feedline

Paul Baldock pbaldock at
Sat Apr 16 10:48:55 PDT 2011

Google the K9AY controller by K9AY (the original). It uses +ve half 
wave rectified AC, -ve half wave rectified AC, Full wave AC and No AC 
for the 4 conditions, all going down the single coax. Works great.

- Paul  KW7Y

At 12:06 PM 4/15/2011, k2waltk wrote:
>Hey all,
>I was wondering if anyone has built  a circuit to control the switching of a
>pair of two-wire reversible beverages, using only the coaxial feed to carry
>the control
>signals.  The usual design calls for 3 DPDT relays.  One relay is used for
>beverage selection and one each for direction and unused port termination.
>In other words, one relay for the NE/SW directions, another relay for the
>NW/SE directions and the third relay is used to select between the two
>reversible beverages.  The truth table is straight forward, but the
>circuitry to accomplish this is beyond this old, feeble brain addled with
>advanced CRS.  I can't figure out the circuitry (diode matrix?) to route the
>control signals to the 3 relays.  I understand how to isolate DC from RF,
>through the bias-T method and I've seen designs using positive, negative and
>AC to accomplish 'generic' remote antenna switching.  Maybe I can use a
>similar method to build the control switch back at the shack and the remote
>relay box.  Any of your suggestions, diagrams or references would be greatly
>                                     73 de Walt - K2WK
>                                     Gordonsville, VA
>UR RST IS ... ... ..9 QSB QSB - hw? BK

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