Ruined Radios And A Dual Beam Scope

After being laughed out of the Derby & District Amateur Radio Club Home-brew Competition, I thought I'd have a go at going commercial. A CODAR CR70A. This radio introduced me to The 1930 Net, the Top Band natter-net on 1930kHz at 1930GMT. With the closure of the Coastal Stations this June, it's good to hear 160m alive again.

It fitted well on my bedside table - you could almost read by the dial lamps. Was it RNI or a parallel interest in Hi-Fi that has embedded Lucky Man by Emerson Lake and Palmer in my memory? And to think ELP are now the theme to The Generation Game. Proof that nothing is sacred.

Did I modify the Codar? Er, the normal output stage was a Class A ECC81 but with the EZ80 rectifier usurped by silicon, it made way for a 6BW6. A wonderful radiogram quality due to hideous mis-matching. Minutes of happy listening until the mains transformer burnt out.

It was replaced by a PCR Receiver. I liked this little radio. Made by Philips Lamps, it was really a domestic set made up for NAAFI Service. It was chosen because the dial lamps shone as bright as the CODAR so I could carry on reading in bed. How I don't know.

Little? The PCR was about the size of a PC base unit. Small in the world of militaria.

New readers now know you are dealing with high-end engineering. It needed the best test equipment. The best you could get for £22. The HARTLEY ELECTROMOTIVES 13A OSCILLOSCOPE was the toy of toys. Dual beam with only 807-class valves for gain to a 5-inch tube with 3000 volts on the plate, it got as hot as hell. Spent most of its time monitoring audio, stuff like Walter Carlos' Switched On Bach, the nearest I ever got to drugs.

Use the scope as a TV Monitor. To do this, feed CRT cathode signal via Z MOD link to scope. Bond scope earth return across to a live TV chassis and take X and Y drive from the timebases. Watch Vision On in a 3 by 4 inch green/black display with a perfectly good 21 inch monochrome picture on the telly right next to it.