[ARC5] Pipsqueack Info - SCR-522

[Mike Morrow]

Last November, Jack Antonio described the interplay of the RC-96 Pipsqueak system (BC-608-A contactor/timer, BC-616 relay box) with the SCR-274-N:

>The BC-616 box does a couple of things. First off, is that for
>the first second of the transmit cycle, the radio is keyed on
>the channel selected by the control box, with MCW.  For the
>rest of the cycle, the transmitter is switched to channel one
>with no tone.

That MCW tone was 1000 cps, and the keying cycle was 14 seconds out of every minute.

I promised to research how the BC-608-A contactor/timer controlled the SCR-522 VHF command set.  The BC-608 connects directly to the SCR-522 with no equivalent external relay box like the BC-616 being required.  I found my latest copy of the SCR-522 maintenance manual, and can now report:

For early BC-625-A transmitters:  When the BC-608-A contactor closes, a 1000 cps tone is transmitted on whichever channel A, B, C, or D is selected on the BC-602 control box.  Less than a second later, a slow release relay in the BC-625-A drops out which stops transmission, selects channel D, then resumes tone transmission on channel D for the remainder of the 14 second contactor closure time.  These actions are very similar to the type of actions that take place on the SCR-274-N, except that the transmitter is always modulated with a 1000 cps tone.

For later BC-625-AM transmitters:  When the BC-608 contactor closes, a 1000 cps tone is transmitted on whichever channel A, B, C, or D is selected on the BC-602 control box for the full 14 second contactor closure time.  The manual also states that in these installations the BC-608 contactor was usually removed and this transmitter control circuit was connected to a "D/F Homing" switch.

Mike / KK5F