Quench Frequency

[mstechca]

This is about the only thing left I have to figure out with my superregen, the optimal quench frequency for the receiver.

One site states a frequency between 25 and 200kHz is good.
Another one claims 20 to 30Khz is good.

I'm a bit confused.

How does the quench frequency affect the whole operation of the receiver?

And let's just say there is one perfect frequency to use. What happens if I go under it? and what happens if I go over it?

 

[audioguru]

Another topic about the same topic. It is best to continue an existing topic instead of starting a new one each time.

I found your last one where Rick Andersen says about his super-regen design, "Another drawback is that the interaction between the main VHF frequency with the 25 KHz quench oscillation causes lots of "hash" -- broadband noise with many minor points on the dial where the audio can be heard; tuning though this can sound like a "fluttering" and it is sometimes difficult to find the exact center of tuning."

I think the quench frequency is affected by the RF input's signal strength.

 

[mstechca]

but the values for the quench frequency are chosen for a reason. It seems in my circuit I currently have a quench frequency of 250Khz, which will be changed. I can't see the input signal electrically changing the quench frequency, but I can see one changing the quench frequency so that it is optimized to match the input signal.

I am still looking for the optimal frequency.

My incoming frequency target is between 100 and 200Mhz.

 

[audioguru]

You don't want the hash points on the dial caused by the quench frequency to be spaced exactly the same as the 200kHz channel spacing on North American FM stations nor whatever the channel spacing is for the aircraft band.

 

[mstechca]

if I were to pick up FM, is it better to make the quench frequency lower or higher than 200kHz and why?

 

[audioguru]

Who knows? Try both. :lol: