Ring modulators and Dalek kits for voice scrambling, shifting and sideband inversion
This is under the 'Receivers' section of this website but there's many other uses. You'll find these videos interesting if you want
to convert upper sideband to lower sideband (or vice versa) or shift audio by a certain amount of kilohertz. That could be useful for
various receiving and other experiments.
Fun with ring modulators for inverted SSB reception
Ring modulators are often used by the electronic music crowd to achieve various audio effects. They are also used by radio hams to build
balanced modulators for SSB transmission and product detectors for SSB reception. This video details some experiments with them.
Australian electronics retailer Jaycar sell a 'Dalek voice modulator' kit that makes your voice sound like a robot's when you speak into a microphone. Just one component change can allow it to do more.
This video discusses how you can use it to subtract audio to allow you to receive lower sideband on an upper sideband receiver (and vice versa). It could also work for transmitting.
Using the Dalek voice modulator kit as an audio frequency shifter
Here I use the above described kit to not invert but shift audio frequencies. Again only a small modification is needed. Why might you do it? Supposing you translated a bandwidth of several tens of
kilobertz in an amateur band. Eg a slab of a CW portion of an HF band. If you sent that into a frequency shifter with a variable local oscillator you'll be able to tune in CW signals on various
frequencies. I haven't done it yet but there's potential interesting combinations with simple phasing direct conversion receivers such as the 2020 80 & 40m QRSS receivers described by PA2OHH.
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Items were chosen for likely usefulness and a satisfaction rating of 4/5 or better.