Regen receivers of the past.
 

G'day all, I recently built myself a regenerative receiver for the broadcast band based on the classic Armstrong circuit using a field effect transistor and whilst it is extremely fiddly to tune, its sensitivity is quite impressive.

I wonder if in the valve/tube days of the past whether any regenerative receivers made any appearance in the consumer market, alongside TRF's and superhets? Regards, Felix (vk4fuq) aka catman.

Hello Felix,

Crosley had a line of regenerative receivers.

IIRC there was a model 51 made in the middle 1920s and others from earlier dates in the mid teens.

Again IIRC the model 51 was a 2 tube radio and there was the Radiola Senior Regenerative Receiver from the early 1920s.

Thanks for sharing the information about your build.

Knight(kit) Span Master comes to mind..

http://www.dxing.com/rx/span.htm

A number of radios in the 20s were regenerative... some shown here:

http://www.radioblvd.com/20sRadio.html

jr

G'day all, many thanks. Fascinating stuff! Regards, Felix (vk4fuq) aka catman.

The Span Master and the following Star Roamer were kit sets from Allied Radio in Chicago. Not Japan or others. I still have my originals of both from my early years. Dad taught me to solder on the Span Master. One divorce later I did the Star Roamer on my own.

The Span Master is tricky to run. The Star Roamer is a standard set more like the day.

If we are including kits... we can't leave out the "Ocean Hopper" Knight Kits:
http://www.ohio.edu/people/postr/bapix/oHopper.htm
Crude, but effective.

jr

Think I have a Philco that used some superregenitive action in the IF amp stage. IIRC (and a good chance I don't) it was this one:
http://www.wa2ise.com/radios/ph1933.jpg
It had a knob on the back of the chassis that could adjust the gain/superregenitive action of the IF tube.

Isn't superregenerative where the oscillation is switched ("squegged") on/off at an ultrasonic rate?

In the case of the Philco it could stand for Superhetrodyne front end Regenerative IF....It could be a good way to squeeze a lot more sensitivity out of a puny single stage IF.

In general terms, in the classical super regenerative receiver, the RF oscillation obtained at the output of the oscillator is applied to a non-linear detector followed by a low pass filter.

The principle of super regenerative receiver is based on the theory of quenching, where a quench oscillator causes repeated build up and decay of oscillations and the oscillations are maximum at the zero crossing where the quench signal goes towards the positive half cycle.

The super regenerative detector stage operates simultaneously at three frequencies: the radio frequency of interest, the super sonic quench frequency, and the the audio or baseband frequency.

The super-regenerative detector constitutes a sampled-data system; that is, each quench period samples and amplifies the RF signal.

These were popular in the early days of RC model airplanes because of low parts count, low weight and low power consumption.

In modern times they have found applications in short range sensor and radio control, such as garage door opener receivers and wireless key less locks.

The next step up is the synchronous super regenerative receiver. In this application the quench frequency is much lower and a PLL is required.

But it still has the advantage of low parts count and low power consumption and of course good sensitivity.

G'day mate, interesting on the 'super' regenerative circuit. Apparently the operation is a lot more complex than first imagined.

I think that I'll stick to the basic regenerative circuit as it gives me plenty of squeals and assorted noises to 'enjoy'. Hi. Regards, Felix (vk4fuq) aka catman.

A regenerative receiver can be more interactive (fun) to use.

Sorry that I drifted a ways off topic.

I'm glad you are enjoying yours.

G'day mate, I'm going to try to make the assembly a bit more decent looking and 'neater' today. I was going to 'box it', but the idea of a bread-boarded assembly is somewhat appealing! Regards, Felix (vk4fuq) aka catman.

Brits and Euros use the term "reaction" for regeneration (wunner what they use for super-regeneration):smoke:
Here's an early Philips 'reaction' set..
http://www.tuberadio.com/robinson/museum/Philips_930A/

A very popular set in the early twenties was the Radiola III two-tube, one stage of regenerative detection and a stage of audio. The III-A added two more tubes and could drive a speaker. I have a III from 1924 and it easily picks up anything an ordinary superhet can all over the eastern U.S. at night with just fifteen feet of wire. It doesn't like too much antenna which tends to load it down and keep it from regenning.

There are countless versions of regen circuits and much written about them. They were popular with amateurs even into the 1930's due to the great sensitivity possible with few components. The touchiness in operation can be reduced with proper shielding and often a regenerative detector tube "likes" a particular B+ voltage for smooth operation: often voltages from 12 to 22 volts work better than higher voltages.

G'day all, well I finished it this afternoon, built on a wooden 'cutting board'. It works well but the setting of the regeneration trimmer capacitor is critical! Regards, Felix (vk4fuq) aka catman.

The Philco model 57, was my mother's first radio. It used an autodyne converter and regenerative IF setup. There was a knob on the back, but it was a band selector. The regeneration setting was a trimmer on the back of the chassis. The Philco model 80, 84 and 37-84 was similar. They were referred to as Philco Jr's.

BTW, Don't forget about all the CB sets and the "Benton Harbor" lunch boxes, that were popular in the late 50's, early 60's.
The Fremodyne FM receivers of the late 40's, early 50's.
Also the German "peoples receivers".

Cool.:yes:
If you use a pot across the tickler instead of a trimmer cap, it makes adjustment much less finicky. Also doubles as a volume control. I always used a 50K pot.