I feel that I understand something when I can explain it to
a rank amateur such that they will also understand it, but
one thing I have yet to understand is the purpose of the quenching
action in superregeneration, apart from thequenching itself.

How does the quenching of an oscillating stage yield a detector
that works for AM, FM and / or SSB, when the quenching frequency
is supersonic, and neither at the RF nor the AF frequencies?

"Brian Morrison" wrote in message
...
On Wed, 7 May 2014 17:00:29 +0100
gareth wrote:

I feel that I understand something when I can explain it to
a rank amateur such that they will also understand it, but
one thing I have yet to understand is the purpose of the quenching
action in superregeneration, apart from thequenching itself.

How does the quenching of an oscillating stage yield a detector
that works for AM, FM and / or SSB, when the quenching frequency
is supersonic, and neither at the RF nor the AF frequencies?



The quench kills the gain cyclically, allowing the RF stage gain to
build up again until the next quench. The result is that the RF, quench
and AF frequencies are all present at the output of what is essentially
a self-oscillating mixer.

But what does the quench DO? What it its purpose? Why not just let
the oscillator run for the self-oscillating mix?

"Brian Morrison" wrote in message
...
Well the point is that if you let the oscillation build up
sufficiently then the gain becomes so high (super regens are designed
to have massive static gain in the RF stage but high Q feedback means
that it takes time to ramp up) that the output limits and the audio
spectrum you're looking for is no longer present, there is just the RF
frequency rail to rail.

OK, now I understand.

The purpose of the quench is to keep an over-excited stage item calm and
usable.

How does one quench M3OSN?

How does one quench M3OSN?



squelching him would be better.......

"gareth" wrote in message
...
I feel that I understand something when I can explain it to
a rank amateur such that they will also understand it, but
one thing I have yet to understand is the purpose of the quenching
action in superregeneration, apart from thequenching itself.

How does the quenching of an oscillating stage yield a detector
that works for AM, FM and / or SSB, when the quenching frequency
is supersonic, and neither at the RF nor the AF frequencies?


Everything I wanted to know, and more besides ...

http://www.eix.co.uk/Articles/Radio/Welcome.htm

Thanks, BrianM, but google never occurred to me. But perhaps it is always
best to attempt technical discussion in the NG to encourage newcomers,
even though M3OSN will attempt to stifle such dissemination of information?

On Wed, 07 May 2014 19:38:13 +0100, gareth wrote:

"gareth" wrote in message
...
I feel that I understand something when I can explain it to
a rank amateur such that they will also understand it, but one thing I
have yet to understand is the purpose of the quenching action in
superregeneration, apart from thequenching itself.

How does the quenching of an oscillating stage yield a detector that
works for AM, FM and / or SSB, when the quenching frequency is
supersonic, and neither at the RF nor the AF frequencies?


Everything I wanted to know, and more besides ...

http://www.eix.co.uk/Articles/Radio/Welcome.htm

Thanks, BrianM, but google never occurred to me. But perhaps it is
always best to attempt technical discussion in the NG to encourage
newcomers, even though M3OSN will attempt to stifle such dissemination
of information?

Well, it doesn't fit in very well with the policy of discouraging
homebrew. If someone builds a regenerative rx, it is depriving the rig
sellers of trade. In turn, the advertising revenue falls - leading more
retailers to seek advertising opportunities elsewhere.

So while we see this as wrong, it is all in a day's work for the great
and good. From a commercial perspective, I can see their point.

On Wed, 7 May 2014, gareth wrote:

I feel that I understand something when I can explain it to
a rank amateur such that they will also understand it, but
one thing I have yet to understand is the purpose of the quenching
action in superregeneration, apart from thequenching itself.

How does the quenching of an oscillating stage yield a detector
that works for AM, FM and / or SSB, when the quenching frequency
is supersonic, and neither at the RF nor the AF frequencies?

Howard Armstrong came up with the regenerative receiver about 1914,
positive feedback making a stage get a lot more gain, and of course if you
weren't careful, it would kick into oscillation, which also showed that
tubes could be used to generate radio frequencies.

But the point where things were "just right" was critical, and was
affected by the antenna swaying in the wind, or the operator's hand coming
close to the front panel. A result was the receiver often went into
oscillation when not desired, a loud squeal in the ear.

Then Armstrong came up with the superheterodyne receiver in 1918, which
has nothing to do with it, but I like the sequence.

He had patent problems, Lee de Forest challenging his patent on
regeneration, so in 1922 before the case came to trial, he did some new
experimenting with the regen, and came across a phenomena he'd noticed
earlier but had never pursued. That was what became superregeneration.

The superregen is just a regen with quenching added. Obviously Armstrong
got the early results because the same stage could be the regen and the
do the quenching, but the quenching could be a separate stage. Indeed,
the superregen has become a kind of black box, people repeating what they
heard, explaining how the same stage can also quench, rather than explain
how the process works. SHow a separate quenching oscillator, and you see
that it is just a regen that's being "modulated". That explains why the
superregen always has such a wide bandwidth, modulate anything with a
square wave and you get lots of sidebands.

No, I still don't get what happens, but by adding the quenching, the regen
became more stable. It was never able to go into oscillation, and for a
lot of purposes that was good. They helped homestead the higher
frequencies, they weren't perfect but they were better than trying to use
a regen up there. And for a lot of consumer equipment (garage door
openers, 27MHz license free walkie talkies), they were simple and cheap
receivers that didn't need adjusting.

SUperregens are primarily for AM. FM comes from slope detection (and
since the bandwidth of a superregen is basically way too wide, they are
really only good for FM reception if the signal is wideband, like FM
broadcast. Otherwise, the narrow deviation provides too puny an audio
signal. They will not work on SSB, since they never go into oscillation,
needed to provide the beat signal to convert the SSB signal down to audio.

That said, since a superregen is just a regen with quenching, you can with
the right adjustment have a regen go into superregeneration. It's not
common, but I know one ARRL VHF receiver did that, allowing for all modes
(though in that case, they had the receiver at 14MHz and a converter ahead
of it).

Charles Kitchin about 20 years ago went back and looked at early work on
the superregen, and wrote about it for Communication Quarterly. And he
discovered that if the quench waveform and depth was adjusted, one could
have better control over the bandwidth of the receiver. I know when I
actually saw a superregen schematic with a separate quench oscillator (it
was around that time, but I hadn't heard of what Kitchin was doing), it
made sense that the wide bandwidth came from "modulating" the regen
receiver. But most of the books by that time had only the vaguest of
information.

Over the years, there were endless articles about getting rid of the wide
bandwidth, but it seems like everyone was looking in the wrong place.
High-Q circuits for 2meter receivers, apparently that helped, but still
not real narrow bandwidth. There was some article in Ham Radio in the
sixties about adding a diode to kill the hangover, that seemed to help,
but still just an incremental change. But in one of Kitchin's articles,
he claims to be able to receive 2m FM (ie narrow deviation) with the
superregen described.

Michael

"gareth" wrote in message ...
I feel that I understand something when I can explain it to
a rank amateur such that they will also understand it, but
one thing I have yet to understand is the purpose of the quenching
action in superregeneration, apart from thequenching itself.

How does the quenching of an oscillating stage yield a detector
that works for AM, FM and / or SSB, when the quenching frequency
is supersonic, and neither at the RF nor the AF frequencies?

You know as kids, during WWII, we played around with single O1A's in regens and learned that if one could control the amount of feedback there was a point just prior to bursting into oscillation, the gain (sensitivity) was incredible! (at night, the Mexican super stations could be heard anywhere in the US)
Controlling the feedback at that super critical amount was almost impossible. As others related, antennas swinging in the wind, or "hand capacity" to the front panel were among the problems.
There were a few articles published (wish I could remember those sources) that brought up the "super regen" where the gain or feedback was modulated around that critical spot. This, apparently allowed the gain of this one tube monster to rapidly go just into oscillation and back out of oscillation, at this super high gain condition in bursts at near an audio frequency rate........ isn't this the effect called "quench"?
I'll bet Mr. Black could set me straight on that!

Oh, but the simple, one tube versions were noisy! noisy! noisy! That characteristic rushing noise which quickly identified a properly operating superegen, like the little "lunch boxes" was awful! Sorry about wasting so much of your time!

Old Chief Lynn, W7LTQ

On Wed, 07 May 2014 19:01:46 +0000, Steve wrote:

Well, it doesn't fit in very well with the policy of discouraging
homebrew.

Sorry, I may be dense but who's policy is it to discourage homebrew?
I accept that to be a 'good' citizen one is meant to sit back and consume
but I don't see any actual policy.



--
M0WYM
Sales @ radiowymsey
http://stores.ebay.co.uk/Sales-At-Radio-Wymsey/

"Wymsey" wrote in message
...
On Wed, 07 May 2014 19:01:46 +0000, Steve wrote:

Well, it doesn't fit in very well with the policy of discouraging
homebrew.

Sorry, I may be dense but who's policy is it to discourage homebrew?

It was a response to a disparaging remark by M3OSN