On Sat, 13 Nov 2004 07:20:09 GMT, m II
wrote:


Is the Superheterodyne set over rated?
Useful Bandwidth control and true synchronous detection are things you
cannot do with a Regen. Try receiving SSB or FM with a Regenerative
receiver.


It seems to me there were
certain advantages to the OLD ways. Ease of control perhaps not being
one of them.

What was the WORST feature of the Regenerative sets?
Selectivity and stability . Calculate the Q required for a 5Khz
channel at 20 Mhz...

The BEST feature?
Simpllicity. You could build a fairly useable radio with just 3
stages, in fact quite a few 27 Mhz walkie talkies were built that way,
with the Regen detector doubling as the Oscillator/output stage in
transmit.

Would it be worthwhile to build a kit?






mike

matt weber ) writes:
On Sat, 13 Nov 2004 07:20:09 GMT, m II
wrote:


Is the Superheterodyne set over rated?
Useful Bandwidth control and true synchronous detection are things you
cannot do with a Regen. Try receiving SSB or FM with a Regenerative receiver.


You most definitely don't need a synchronous detector for SSB reception;
indeed there is nothing to synchronize to. One can argue that the "direct
conversion receiver", ie a mixer and oscillator that translates the signal
directly to audio, is just a variant on a regen set to oscillate in order to
likewise beat the signals down to audio. A regen does have its limits
when it comes to SSB, including the lack of selectivity and since they
were built for simplicity, lack of stability.

Synchronous detection is not need for FM, either. What may be fooling you is
that one way to detect FM is to use a phase locked loop that tracks the
incoming signal; the feedback voltage hence follows the modulation of the
signal and recovers the audio. There are plenty of other FM detectors, but
yes the regen isn't usually one of them. Theoretically it can be used
like any AM detector to demodulate FM by mistuning and "slope detection".


The BEST feature?
Simpllicity. You could build a fairly useable radio with just 3
stages, in fact quite a few 27 Mhz walkie talkies were built that way,
with the Regen detector doubling as the Oscillator/output stage in
transmit.

Actually, regens were rarely or never used for those applications. It was
the superregen, also patented by Howard Armstrong, that was used. It
was an extension of the regen, the addition being quenching of the detector
at frequency in the hundreds of kiloHertz range. This pulsing of th
regen detector allowed for maximum gain without the instability of the
regen going in and out of oscillation. It also results in a much wider
bandwidth. Note that the superregen is promoted for reception of FM, though
in its case it is slope detection.

Michael

On 14 Nov 2004 03:15:13 GMT, (Michael Black)
wrote:


matt weber ) writes:
On Sat, 13 Nov 2004 07:20:09 GMT, m II
wrote:


Is the Superheterodyne set over rated?
Useful Bandwidth control and true synchronous detection are things you
cannot do with a Regen. Try receiving SSB or FM with a Regenerative receiver.


You most definitely don't need a synchronous detector for SSB reception;
Actually you are taking that out of context. Synchronous detection is
useful only for AM, and a Regen cannot deal with selective fading any
better than a standard envelope detector can.

The fact is however, that synch detection is unavailable on a regen,
because you need to phase lock to the original carrier. In theory a
Regen can handle SSB, in practice it cannot due to lack of a stable
carrier, lack of a product detector, and inadquate sensitivity. YOu
can get SSB without a product detector, as long as the injected
carrier is very large relative to the SSB signal so the envelope
detector is operating in a linear part of the V/I cure. NB fm can be
slope detected, standard FM cannot, it is much too wide for slope
detection work. NB FM is mathematically the same as AM with a low
modulation index.

Synch detection isn't much good for FM.

On Sun, 14 Nov 2004 23:02:15 -0700, matt weber wrote:
Regen can handle SSB, in practice it cannot due to lack of a stable
carrier, lack of a product detector, and inadquate sensitivity.

Of course a regen rx can handle SSB. My 3-tube set works fine on the 80m
and 40m ham bands. Naturally, the tuning needs an occasional tweak but
once it has warmed up it will stay on an ssb signal for quite some time.
Selectivity is not an issue - that is done at audio like a direct conversion
set. Tests by ZL2JJ have shown a good regen receiver to be as sensitive as
many modern superhets.

The German military were using regen receivers* right through WW2 for
AM and CW reception and if you can resolve CW you can handle SSB.

* For example the excellent Hagenuk Ha6K39b tranciever.
--
Cheers,
Stan Barr stanb .at. dial .dot. pipex .dot. com
(Remove any digits from the addresses when mailing me.)

The future was never like this!

On 15 Nov 2004 18:34:05 GMT, (Stan Barr) wrote:

On Sun, 14 Nov 2004 23:02:15 -0700, matt weber wrote:
Regen can handle SSB, in practice it cannot due to lack of a stable
carrier, lack of a product detector, and inadquate sensitivity.

Of course a regen rx can handle SSB. My 3-tube set works fine on the 80m
and 40m ham bands. Naturally, the tuning needs an occasional tweak but
once it has warmed up it will stay on an ssb signal for quite some time.
Selectivity is not an issue - that is done at audio like a direct conversion
set. Tests by ZL2JJ have shown a good regen receiver to be as sensitive as
many modern superhets.

The German military were using regen receivers* right through WW2 for
AM and CW reception and if you can resolve CW you can handle SSB.
WRONG! There is no requirement that that the envelope detector be
linear. BFO and a Diode detector will work just fine for CW. It
doesn't work very well at all on SSB unless the BFO signal level is
much much greater than the SSB signal level.

Phase and waveform distortion have no impact the ability to receive
CW. They have a pretty serious impact on the SSB quality.

On Mon, 15 Nov 2004 17:17:25 -0700, matt weber wrote:
WRONG! There is no requirement that that the envelope detector be
linear.

It *must* be non linear otherwise no detection takes place...

BFO and a Diode detector will work just fine for CW. It
doesn't work very well at all on SSB unless the BFO signal level is
much much greater than the SSB signal level.

Phase and waveform distortion have no impact the ability to receive
CW. They have a pretty serious impact on the SSB quality.

Nope! My regens produce fairly good quality ssb...as does my Racal
RA-17 which doesn't have a product detector either. Resolving ssb is a
mixing process, any form of mixing device will do the job, and a product
detector is just a (non-linear) mixing device (which may be made from
diodes). A regen detector in ssb/cw mode is a tube or transistor self-oscillating mixer and makes a quite good ssb detector.

Obviously a well-designed product detector is *better* at ssb detection
though, but simple detectors can work well.

Anyway, playing around with simple regen sets is good fun... :-)

--
Cheers,
Stan Barr stanb .at. dial .dot. pipex .dot. com
(Remove any digits from the addresses when mailing me.)

The future was never like this!