This one is a simple crystal receiver with one stage of AF amplification. It covers the AM broadcast band, the HF bands, and (apparently) VHF using a switch and three different coil/capacitor combinations. You could make it a lot simpler by just building it for one band. Looks to me like a nice rig for an Altoid tin.
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Bill - thanks for sharing. There's a couple of oddities about the circuit.
ReplyDelete1. The resistor across the germanium diode - never seen that before
2. The segmented bands. Rather than tune the AM broacast band in one range it tunes it in two. One half of the dual gang tuning capacitor is used only for the lower range (300 - 500m or 0.6 - 1 MHz).
Bigger coils would have allowed a full 0.5 - 1.6 MHz range with the capacitor shown (gangs wired up). But tuning on shortwave would have been much coarser.
However I don't think it covers VHF - the highest it goes with the coils is 15m (20 MHz).
73, Peter VK3YE
Hi Bill,
ReplyDeleteIf you like reading old Italian technical magazines have you seen this site?:
http://www.introni.it/riviste.html
Should keep you busy for quite some time!
73; Kevin