George Ramlow's Shortwave Receiver

Regenerative Shortwave Receiver Front View

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The receiver is a generic one-tube Armstrong regenerative using screen voltage to control regeneration. Not a lot of creativity or innovation with this one. I have some more complex receivers that I could have used, but I wanted to see what a one tuber could do. The tube used is a 1C5GT that was declared deceased by a former owner, but a 1Q5GT would work as well. I wound two coils for it. One covers ~5.2 MHz to ~11 MHz, while the other covers ~9 MHz to just over 20 MHz. I attribute the smaller tuning range on the first coil to the fact that it was close-wound and thus has more inter-winding capacitance. The antenna is coupled to the tank circuit via a 25 pF variable capacitor and a 2.5 turn link.

The antenna is about 60 feet of wire strung between a couple of trees in my back yard, and down to my patio cover. It's about 8 feet off the ground, but the trees are on a slope, so the distance from highest point to the receiver is probably more like 12 feet. Pretty makeshift, but better than the wire I have running around the floor of my bedroom. I didn't use a ground.

Overall, I was pretty pleased with the results, considering the simplicity of this receiver. I could receive almost everything my spotter (Grundig G6) could, but there were quite a few stations that I couldn't log because they were too faint, and I wanted to resist the temptation to add an audio amp or sound powered phones. There were a few others that I couldn't ID, so I didn't log them, either. Hand capacitance wasn't a problem, despite not having a grounded metallic front panel.

George Ramlow, AE6XF

Regenerative Shortwave Receiver Internal View

Regenerative Shortwave Receiver Schematic

See George's entry in the 2011 RadioBoard Contest