Rick Andersen KE3IJ

In case you missed it, it appears that Rick is SK. The good news is that much of his work is archived on the Wayback Machine. His memory lives on.

See https://web.archive.org/20210430124905/http://www.ke3ij.com/radios.htm

Rick Andersen KE3IJ

Yesterday, I posted a circuit that appeared on Rick's KE3IJ's website back in 2012. This website seems to be no longer there. Does anybody have any information please?

Something for nothing

Like many, I like the idea of getting something for nothing. 

This circuit was on the website of KE3IJ some years ago. I think the website is no longer there. 

The same idea might even work with a microwatt beacon?

Simple Home-Built Radio Projects page

The website of Rick Anderson KE3IJ is one of my favorites as it is filled with simple circuits, mainly simple receivers, that can easily be reproduced and that work well. See http://www.ke3ij.com/radios.htm. What I like is that on many pages there are little extra bits of circuitry that can be used in other projects too.  Lke me, Rick loves the humble 2N3904 transistor which is useful from audio to VHF.  They appear all over the place in his novel circuits.

Free power radios

KE3IJ's always excellent website has a novel receiver circuit that derives its DC power from AC mains hum and noise it picks up on its antenna.  It uses a single 2N3904 in a regenerative circuit. Ideally the circuit would be better with a lower Vbe device i.e. a germanium transistor.

Taking this one stage further, I know from my experiments at VLF that the AC mains hum between a pair of grounded electrodes can be pretty high. There is certainly enough 50(or 60)Hz energy going free in the ground to power something useful. I keep wondering if I could get a few uWs of HF RF power from a low voltage crystal oscillator that would be enough to work some local stations on CW? My nearest station is 0.3km and the next nearest 3km. Now having a QSO using free power from my back garden would be rather fun.

Free power QRPp transceiver or beacon?

The idea of powering a low power receiver, or even a transceiver or QRPp beacon, from free, otherwise wasted, RF energy that is all around us appeals to me. A few people have been toying with this idea and there are even some commercial ICs likely to appear which "harvest" energy from stray RF and even vibrations. The circuit shown here is from the excellent site by KE3IJ (R.Andersen) and shows how to use 50 or 60Hz mains "fog" and stray RF to power a simple receiver. See http://www.tricountyi.net/~randerse/nopower.htm .

See also Ben Tongue's crystal set pages for a circuit using a supercap to store harvested energy which is then used to power a micropower op-amp.

A "harvester" QRPp transceiver or beacon which derives its energy from stray RF, storing this is in a supercap and allowing brief periods of transmission at very low power is worth developing I think. I have not seen such "harvesting" circuits used to power a transceiver or beacon before but for a uW level beacon this should be feasible.