Ladder line Quick connections

[VK4ADC]

Hi OM Jim,

Should you ever need remote operation, a DPDT Latching Relay would be the right choice as it would obviate the need to keep relay coils on continuously.

73,

Nandu.

Nandu

The physical closeness of the pairs of DPDT relay contacts within a single relay unit would not retain the 450 ohm characteristic impedance of the open wire line.  The other issue might be that we don't know what RF transmitter power level is involved so finding a latching relay to handle the RF current might be difficult, let alone the breakdown voltage rating (high Z = high voltages).

Most latching relays require the polarity to be changed for subsequent changeovers so that might complicate the switching control arrangements slightly. (Yes, I am aware that some latching relays have two coils but they aren't commonly found.)

I use SMA latching relays in my microwave transverters and use a "buck" electrolytic capacitor arrangement in series with the coil and the +12V to snap them in quickly and then the quiescent relay current reduces to a very low nominal value. Works well except you must make sure that the latching state is set on initial power-up so that you know which way it is set (ie Tx or Rx).