To Reset Relay


two-way intercom between shacks; (2) remote control of all the separate feedlines for a three-band, two-element quad for 10,15 and 20 meters; (3) remote control of a two-band trap dipole for 40 and 80 meters, and (5) lighted indicators

Since all of the antennas already existed at Phil's, we left them there and I undertook the construction of the switching system. The design considerations were: (1) as little disruption to Phil's shack as possible; (2) a low control voltage between shacks; (3) fail-safe normals so that power supply failure would not inconvenience Phil (after all, I was saving lots of bucks by not having to buy and erect an antenna system); (4) a simple singlevoltage power supply; {5} grounding of all antennas when not in use, and (6) ability to override the other shack - if one operator forgot to clear his control panel, the other still could gain access to any antenna.

There are four sections to the system: the control relays, Phil's control panel, my control panel, and the antenna relays. The basic control relay hookup is shown in Fig. 1.

If I press 51 (a momentary NO SPST push-button switch), K1 pulls in. The lower set of contacts applies a latching ground to the relay coil through two dependent normals: S2 (an NC momentary push-button switch) and an NC set of contacts on K2. 52 is on Phil's control panel and when it is pressed, it resets the condition that S1 set. K2 and S3 allow a momentary break in the ground used to latch K1. I use S3 to reset anything I've remoted, Phil uses S2 to reset the relay if I walk off and leave something remoted.

Point R is connected to all of Phil's switches, allowing reset of any remote condition to my shack.

S1 and S2 have internal lamps that are lighted when K1 pulls in. The lights indicate a remote condition. All bulbs are 28 V dc running on 24 V dc to lengthen life. All control relays are 4PDT 24 V dc.

This circuit is duplicated five times; four for the antenna relay control and the other for rotor control

Sb is a push-on, push-off SPST switch with an inter-

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