/// AG, the letters and number are used for fuses and wire sizes. I am searching for a low (very low) voltage and wattage switching diode. Hams use the arrangement in receiver inputs with small transmitters to avoid putting a relay in the antenna circuit. The two diodes switch on with voltage so that the receiver antenna is shorted together (to ground). When the transmitter is off (morse code) there is no recovery time for the receiver. You can actually hear the receiver between the code dots and dashes you send. The voltage difference in these different situations may require the lower voltage/wattage part. The AG 20 could be 20 milliwatts or some other power designation. If I use a 75 volt 1N914 it will not be as sensitive I suspect.

I got the Hosfelt catalog yesterday and ordered the Allied CD Rom. This may be a proprietary item for car radio manufacturers. I had hoped to find a refurbisher or rebuilder through the manufacturer.

BTW never put a CB duplexer in your car radio antenna circuit. The PO had tried to use the car radio antenna as a CB Antenna. That 4 watts directly into the receiver antenna blew the diodes. Duplexers do work but the theory and why CB Duplexers don't work is too much for a Brickboard post.