Stingray Marine Transceiver

Its been a while since the last post, a lot has happened. It looks like WordPress has changed quite a bit too!

At the Ballarat Hamfest recently, I picked up an old Marine transceiver for a princely sum of $10. What I liked about it was the cast housing and it seemed to have a bit of waterproofing which I guess is no surprise. It was made in Sydney by Findlay Communications. Australia used to have a lot of radio manufacturers once, what a shame most have now disappeared.

I had no idea what condition it was in, I could not go wrong at $10. After getting it home and prising the covers off (they were sealed with a silicone type stuff), it looked pretty good inside. It is crystal controlled with a claimed power output of 120 Watts. Frequency coverage is stated at 2-13 MHz, AM/USB with 10 channels.

Power was applied and a big fat nothing. It didn’t take long to see that the speaker wire was disconnected. After reconnecting, it sprung to life and crackled when a bit of wire was put in the BNC socket.

When the antenna was connected it seemed good and a signal generator confirmed that the sensitivity was good. Next thing was to try transmit. PTT resulted in a soft click from the relay but no change from receive to transmit. Inspection of the relay showed that it had sticky stuff on the armature. Removal of this fixed the problem and it went into transmit on PTT. No output though 😦

I posted a request for a manual on the local forum and was surprised that a guy, John in WA had a manual. It didn’t take long to find a burned out resistor in the PA from the output transformer to ground. The resistor was replaced and power output looked respectable. Something like 50 Watts in AM mode and more in SSB mode.

Crystals are petty expensive if you can get them these days, so I went about replacing the crystal oscillators with an Si5351a controlled by an Arduino. My main aim was to have a boat anchor radio for 160m AM and something on 30m SSB. The radio looked very tatty so I gave it a paint job and made some side grab handles for it out of 5mm thick Aluminium

It all worked out well, and I had the first call on it today to a VK2 on 30m. Good signals and the radio sounded pretty good. The radio has retained a few marine channels and I have added 1.825 MHz AM and 10.125 MHz USB. There is another output on the Si5351a clock generator, so I might add a 20 metre frequency. It would be easy to add a rotary encoder and display but that would probably be over capitalising the radio 🙂 The paint cost more than the radio.