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Sci.Electronics.Basics -> Regenerative Radios
There are 13 messages in this thread.
You are currently looking at messages 1 to 13.
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Author: Dave.HDate: 05:32 26-05-08
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I've been looking for a transistor regen schematic, finally found one,
but it doesn't give the coil specs. I want to receive the AM band,
from 530 kHz-1500 kHz. Any help on this very much appreciated.
http://www.techlib.com/electronics/regen.html
Thanks,
Dave
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Author: Dave.HDate: 06:03 26-05-08
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On May 26, 7:32 pm, "Dave.H" <the19...@googlemail.com> wrote:
> I've been looking for a transistor regen schematic, finally found one,
> but it doesn't give the coil specs. I want to receive the AM band,
> from 530 kHz-1500 kHz. Any help on this very much
appreciated.http://www.techlib.com/electronics/regen.html
>
> Thanks,
> Dave
Would A 180 uH or 470 uH choke work as the coil? If not I will have to
wind my own coil.
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Author: Tom BiasiDate: 06:20 26-05-08
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Author: Dave.HDate: 07:48 26-05-08
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On May 26, 7:32 pm, "Dave.H" <the19...@googlemail.com> wrote:
> I've been looking for a transistor regen schematic, finally found one,
> but it doesn't give the coil specs. I want to receive the AM band,
> from 530 kHz-1500 kHz. Any help on this very much
appreciated.http://www.techlib.com/electronics/regen.html
>
> Thanks,
> Dave
I found another circuit, that uses a 2N3904, at
http://home.pacbell.net/lengal/ip/amregen.pdf
Can I leave the LM386 amplifier out, and could I use a 3.5 inch coil
form with SWG21 wire? The schematic has two specs for the coil, which
one is for AM? I'm not good with working with coils, I know how to
wind them, that's about it.
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Author: Don BoweyDate: 09:59 26-05-08
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Author: Don BoweyDate: 10:05 26-05-08
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On 5/26/08 4:48 AM, in article
28f3ebd3-ccff-4872-813d-05a5a460aa4d@u12g2000prd.googlegroups.com, "Dave.H"
<the1930s@googlemail.com> wrote:
> On May 26, 7:32 pm, "Dave.H" <the19...@googlemail.com> wrote:
>> I've been looking for a transistor regen schematic, finally found one,
>> but it doesn't give the coil specs. I want to receive the AM band,
>> from 530 kHz-1500 kHz. Any help on this very much
>> appreciated.http://www.techlib.com/electronics/regen.html
>>
>> Thanks,
>> Dave
>
> I found another circuit, that uses a 2N3904, at
> http://home.pacbell.net/lengal/ip/amregen.pdf
> Can I leave the LM386 amplifier out, and could I use a 3.5 inch coil
> form with SWG21 wire? The schematic has two specs for the coil, which
> one is for AM?
Both are for the BCB, Use the one that matches the tuning capacitor you
want to use.
> I'm not good with working with coils, I know how to
> wind them, that's about it.
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Author: Tom BiasiDate: 10:39 26-05-08
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Author: Dave.HDate: 12:39 26-05-08
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On May 26, 9:48 pm, "Dave.H" <the19...@googlemail.com> wrote:
> On May 26, 7:32 pm, "Dave.H" <the19...@googlemail.com> wrote:
>
> > I've been looking for a transistor regen schematic, finally found one,
> > but it doesn't give the coil specs. I want to receive the AM band,
> > from 530 kHz-1500 kHz. Any help on this very much
appreciated.http://www.techlib.com/electronics/regen.html
>
> > Thanks,
> > Dave
>
> I found another circuit, that uses a 2N3904,
athttp://home.pacbell.net/lengal/ip/amregen.pdf
> Can I leave the LM386 amplifier out, and could I use a 3.5 inch coil
> form with SWG21 wire? The schematic has two specs for the coil, which
> one is for AM? I'm not good with working with coils, I know how to
> wind them, that's about it.
What pins would I connect to on the LM386? I just found one of these
in my junk box, and want to use it.
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On Mon, 26 May 2008, Dave.H wrote:
> I've been looking for a transistor regen schematic, finally found one,
> but it doesn't give the coil specs. I want to receive the AM band,
> from 530 kHz-1500 kHz. Any help on this very much appreciated.
> http://www.techlib.com/electronics/regen.html
>
First, you actually may get more out of the project by tuning shortwave
frequencies. IN the broadcast band, you the regen won't actually mean
that much on local stations, you may also find that the ease with
which a regen can kick into oscillation will be annoying on the broadcast
band that consists of AM signals, since the oscillation will beat against
the carrier of the station and cause an annoying beat note.
On shortwave, you get new territory, and the gain of the regen will start
being useful. Plus, you'll come into contact with signals that require
the regen to go into oscillation, so you get to sample that.
On another matter, the thing about regen receivers is that they've often
focused on simplicity. In the beginning, that reflected the cost of
components, but then in more recent decades it's because there are better
reception schemes, which are complicated, so the only reason to use
regenerative receivers was for the simplicity.
Yet, modern components have made it so easy to make things better. In
the days of tubes, nobody wanted to add extra tubes since the cost was
there and it increased the size of the receiver. But semiconductors are
outright cheap, and their size means you can have hundreds or more
transistors in the space that one tube took up.
Charles Kitchin has done quite a bit of work on regen and superregen
receivers, going back to the beginning (instead of cascading on what's
been there recently), trying to distill the basic concept and seeing
how to improve upon it. He's published quite a few different regen
receivers (and some superregens) that are still relatively simple
yet don't go for the fewest of components.
So he'd add a stage of amplification before the regen detector, not
because amplification was needed, but because it isolated the detector
from the antenna, so the antenna moving around had less affect on
the regen's operation (in the old days, a single stage regen would
pop into oscillation because the antenna waved in the wind). It
complicates the electronics, though only relatively speaking, but
it simplifies useage. He'd add voltage regulation, again to help
stabilize the amount of regeneration so it didn't suddenly pop
into oscillation. In the tube days, voltage regulation would require
another big tube, in solid state times, it's a diode or three terminal
regulator, nice and easy.
But most of his designs have also focused on being easy to build. So
he uses things like 35mm plastic film boxes to wind the coils, though I
suppose at this point those are getting scarce as film cameras disappear.
In at least one design, he used a varactor for tuning, to sidestep
the issue of getting a variable capacitor. He even had one that
used a crystal for frequency selection, useless for most purposes
but great when there was a code practice station on that frequency.
So you might do a search on "charles kitchin", at least some of his
designs have appeared on the web.
Michael
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Author: AllenDate: 15:40 26-05-08
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On Mon, 26 May 2008 18:39:47 +0200, Dave.H <the1930s@googlemail.com> wrote:
>
> What pins would I connect to on the LM386? I just found one of these
> in my junk box, and want to use it.
Before somebody swears at you, have you considered browsing to your
favourite
search engine and entering 'LM386 datasheet'? It's free, it shows
initiative,
and you'll get a result FAR more quickly than waiting for somebody to do it
for you.
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Author: christofireDate: 17:28 26-05-08
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"Allen" <allen.versfeld@gmail.com> wrote in message
news:op.ubr0x3xxh37c9k@supermole.mole.boldlygoingnowhere.org...
> On Mon, 26 May 2008 18:39:47 +0200, Dave.H <the1930s@googlemail.com>
> wrote:
>
>
>>
>> What pins would I connect to on the LM386? I just found one of these
>> in my junk box, and want to use it.
>
> Before somebody swears at you, have you considered browsing to your
> favourite
> search engine and entering 'LM386 datasheet'? It's free, it shows
> initiative,
> and you'll get a result FAR more quickly than waiting for somebody to do
> it
> for you.
I couldn't agree more. In fact, at the risk of sounding like a boring old
fart (or a teacher), nowadays there seems to be little point in constructing
any kind of simple radio other than for the purpose of discovering for one's
self how the things work, how they're designed and put together, and what
the design options are. Asking people in a Usenet group for elementary
stuff like this just seems bonkers and counter-productive - if the desire is
only to obtain a working radio with the least effort then the best solution
is to visit a pound shop (in the UK; five and dime, etc. elsewhere).
But perhaps any blame should be shared by all the willing, helpful
collaborators (including myself on occasion) who rise to the bait! Perhaps
if every banal request was met by a standard 'go Google it' response every
time the perpetrators would get the message and become bored of asking the
obvious. The grey area would be those requests for which the responses
sometimes turn up facts useful to others.
Chris
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Author: Don BoweyDate: 18:37 26-05-08
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On 5/26/08 9:39 AM, in article
4be06470-5d11-4f82-af17-bfdd6f6423a2@u12g2000prd.googlegroups.com, "Dave.H"
<the1930s@googlemail.com> wrote:
> On May 26, 9:48 pm, "Dave.H" <the19...@googlemail.com> wrote:
>> On May 26, 7:32 pm, "Dave.H" <the19...@googlemail.com> wrote:
>>
>>> I've been looking for a transistor regen schematic, finally found one,
>>> but it doesn't give the coil specs. I want to receive the AM band,
>>> from 530 kHz-1500 kHz. Any help on this very much
>>> appreciated.http://www.techlib.com/electronics/regen.html
>>
>>> Thanks,
>>> Dave
>>
>> I found another circuit, that uses a 2N3904,
>> athttp://home.pacbell.net/lengal/ip/amregen.pdf
>> Can I leave the LM386 amplifier out, and could I use a 3.5 inch coil
>> form with SWG21 wire? The schematic has two specs for the coil, which
>> one is for AM? I'm not good with working with coils, I know how to
>> wind them, that's about it.
>
> What pins would I connect to on the LM386? I just found one of these
> in my junk box, and want to use it.
How about this thought?
You sketch out what you think you must do to make it work, scan it, and post
it to a.b.s.e. Then ask for comments. You'll get much more out of it that
way.
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