After information (hopefully a schematic) for the VSR5 Marine HF transceiver (and its matching speaker and vibrator PSU). Its from the mid 1960s and is proving to be very elusive on the internet......... Found a reference in a museum archive, and a mention of it in a book on the history of radio in Sth Aust. Note much else and no technical info. Anything appreciated...

I would expect some maritime museums just might have something as it is a more specialised field along with Ham Radio. There will be Ham Radio people au fait with such things.

Aside from a couple of CB radio's. The only valve one which I have done work on, was a Wireless Set 19, but at least I had paperwork for it. I still consider that it like a lot of allied miliary stuff, it was "designed" to be blown up, not fixed up.

I am currently rebuilding a VSR5. It was badly hacked by someone trying to turn it into a CW ham transceiver(!) and was a bloody mess, so I have started over. Because the coils were hacked, as well as the circuit, I have decided not to restore it per se, but turn it into something workable to possibly use on 80m and 40m AM.

The receiver circuit is straight from an RCA tube manual 'Automobile receiver'.

The transmitter is a 6AQ5 Pierce xtal oscillator driving a 6V6, choke-modulated by the receiver audio 6V6. Vaughan claimed 16W input, but I think that 16W includes the audio 6V6, as there is no way that a single 6V6 could modulate a 16W input! An interesting aside is that the speaker transformer is switched into the PA cathode on transmit, giving simultaneous plate and cathode modulation.

I had one of these years ago, with the vibrator supply/speaker, but it got junked in a flood. HT is 250V. Check the tubes, both 6V and 12V versions were made. My current one is a 6V one from the early 50s. My previous one was a 12V model, maybe a bit later, with a chrome, er, rusty dial escutcheon. The 12V ones used 12V tubes, with the 6V6 heaters in series.

I am attaching a scan of the receiver schematic (it really is basically identical, except for the oscillator wiring around the 6BE6) and an old ad from the Fisheries Newsletter.

I have some old experience with AM transceivers on the 75 to 80 MHz VHF low-band commercial (think taxi radios).

A 10 watt transmitter could be plate modulated with a single 6V6-style bottle. To get as much talk energy as possible into the sidebands and cut through the noise the modulator was driven well into clipping (10 watts at 75% THD!) and this also avoided over-modulation.

AM VHF would play havoc with lots of audio gear and even car radios in nearby cars! Testing one in the workshop into a dummy load would crash every computer in the building. And then there was that rock concert in Newcastle (but we won't talk about that, it was a long time ago!)