"Alan Horowitz" wrote in message
om...
Is there a place in modern technique for regeneration (Q-multiplication)?

I guess that depends on the application. I don't know how true it is, but I
believe I saw that some of the 433 MHz ISM band receivers use either
regenerative or superregenerative detectors. They are tiny and have
sensitivities better than -106 dBm.

There has been new work on superregens (September/October 2000). An article
was published in QEX, a ham radio journal. The first file at
http://www.arrl.org/tis/info/vhfproj.html is that article but it requires
membership to get it. However, on the same Web page, I see another that
appears to be available without membership. It is An Ultra-Simple VHF
Receiver for 6 Meters .

You can probably contact the ARRL and buy a reprint of the first article. It
is well worth it. The author, Charles Kitchin, says the gain in a superregen
detector is about a million. He discusses his discovery of shaping the
quenching waveform so that selectivity is not lost. And he says it is
possible to receive FM and NBFM as well as AM. It is a very enlightening
article.

I plan to build a superregen to play with. After I get one going, I think I
will try to make it work at 450 MHz. Like some other posters here, I built
my previous regen 40 years ago.

Cheers,
John

I plan to build a superregen to play with. After I get one going, I think I
will try to make it work at 450 MHz. Like some other posters here, I built
my previous regen 40 years ago.

Cheers,
John

Hi John,
I built a few superregens about 40 years ago too!! They were on 288
MHz when Australian amateurs had the one metre band. Surprisingly good
sensitivity for a one-valve receiver (6J6 usually) but of course they
put out a fair bit of rubbish over a fair bit of the band. I often
wonder if the quench frequency could be better controlled - perhaps an
external injection oscillator or something like that. Anyway, best of
luck with your 450 MHz.
Alan
VK2TWB

"John Smith" wrote in message link.net...
"Alan Horowitz" wrote in message
om...

Is there a place in modern technique for regeneration (Q-multiplication)?


I think its possible it might become popular technology again. The
advantage of high gain per cost is attractive, and it has other
benefits. Stability is the prime issue: it can be controlled by low
frequency quenching, which can of course be adaptive. The question now
is whether a simple scheme can be devised that ensures consistent
stability and gain with small quench control circuit cost. If solid
stability is achieved, the rf emission problem is eliminated at the
same time. If its achieved at minimal cost, it may be a winner.

I know I've seen it used in some modern receiver chips, but damned if
I can remember the details.


NT

On Fri, 29 Oct 2004 15:55:06 -0500, clifto wrote:

Bob Masta wrote:
Just thought you'd like to know!

If only you could explain cochlear hydrops in a way that suggested a fix.


I'll ask around about progress on this. When I worked in the hearing
research lab, some folks were trying to come up with an animal model
so that they could study various treatments. At the time, they didn't
have any animals that developed hydrops spontaneously, so they
had to go in surgically to plug things up and prevent normal fluid
flow. I'm not sure it they came to any insights with this approach,
but it seemed a long shot to me. That was maybe 15 years ago,
so they could have come a long way. I still attend weekly seminars
in my old department, so I'll ask around about this.

You probably already know this, but the conventional advice is
to cut salt intake. That basically means you prepare all your own
food from scratch, in light of the amount of salt that restaurants
and processed food contains. Tough job, but easy enough to
try out.




Bob Masta
dqatechATdaqartaDOTcom

D A Q A R T A
Data AcQuisition And Real-Time Analysis
www.daqarta.com