My 1 transistor FM Super-Regen Receiver!

[zlatkoMM]

I don't mean only two fets just for input / mixer stage are used
this two fets then are 3 transistors for IF amplifier then
is freq/voltage converter.
Do you maybe know what i can use to replace this freakin
micro alloy transistors used in sinclair schematic ?
I have tried with BF506 VHF Siemens transistor but he
refuse to oscilate in this circuit ?
I will try also mesa AF239...
or i must find something different from old MW radios ..hmmm

 

[zlatkoMM]

Ok.
I build RF stage of microFM ...and
my first clue is that this circuit not work
because i think that this oscilator is a just modification
of super-regen oscilator BUT i was wrong.
It is a really oscillator-mixer which oscilate on cca 120kHz.
Insted of standard 'hiss' sound produced by any regen this
stage produce only very low noise sound.
So next stage will be IF stage with 3 transistor as cascade amplifier..

 

[zlatkoMM]

Here is another simple FM receiver which use so -called synchro
detector with two transistors.
This circuit work 'out of box'..

 

[zlatkoMM]

Here is fremodyne receiver - minimal superheterodyne receiver
with super-regenerative detector with two RF transistors.
Circuit perform very well and is imune to hand capacitance like
any standard superheterodyne receiver.


- - - Updated - - -

And here is a simple super regen FM receiver with tuning LC
tank in emitter with a low impedance .
Circuit perform good as a super regen .

 

[zlatkoMM]

here is excellent Kosmos X3000 fm super regen

 

[zlatkoMM]

Here is superregen fm receiver with Hartley oscillator.
If you have vericap diode from $1 radio BB910 you can use
power supply +3V

 

[Audioguru]

You forgot to post your Hartley super-regen receiver.
With only one tuned circuit then the selectivity must be awful unless you have only a couple of FM radio stations in your city.
My city has about 30 FM radio stations and other nearby cities all around me also have many FM radio stations. Then on a good quality FM radio the dial is full of stations and good selectivity is important.

Don't you notice terrible distortion on your AM super-regen receivers tuned to one side of an FM station's frequency so it slope-detects the FM?
Do your super-regen receivers produce severe distortion on loud audio from an FM radio station? Because then the RF frequency deviation is the highest and if the tuned circuit in the receiver has high Q then its bandwidth is too narrow.

Does the quenching frequency cause interference with the stereo sidebands or SCA sideband of an FM radio station?

 

[zlatkoMM]

Here is superregen fm receiver with Hartley oscillator.
If you have vericap diode from $1 radio BB910 you can use
power supply +3V

 

[Audioguru]

Your circuit is a simple regenerative (regen) radio, not a super-regen. Your simple regen has a fixed amount of positive feedback (most regen radios have an manually adjustable amount of regen) but a super-regen uses an RC network on the emitter of the oscillator causing it to build up gain then stop and build up gain and stop again over and over (called quenching) resulting in automatic high gain for weak signals and automatic less gain for strong signals.

Your schematic has a dark background that makes it hard to see. I tried to increase its contrast but I couldn't so I lightened it instead:

 

[zlatkoMM]

Here is fm super regen based on Vladimir Poliakov receiver..