[sdiy] AM reciver

[D A F]

If you want to make a simple AM reciever for near-by stations, a simple
crystal set with some added audio gain is all that is needed.  However, I
think if you want to try making a simple AM reciever that has some real
station-pulling power, you can't beat the not-too-much-more complex
regenerative circuit.

I have played with some tube regenerative AM receivers and I think this
would be just the thing for you to make.  The tube can be subbed with a
J-Fet and lower voltages (9 volts or less) used.  With a regen, you can
recieve AM, SSB, Continuous Wave, and even FM (using 'slope detection').
There are tons of regen articles out there.  The appeal is that many times
you only need one active device.  The regerative detector is a resonant L-C
filter and AM detector all in one circuit.  Coils can be wound by hand on
paper tubes (toilet paper, etc.) for all frequency bands.  Variable tuning
caps can be bought fairly cheaply or even home-brewed.  Definitely capable
of lots of strange noises to play with, especially when you allow the regen
to oscillate.

Dave




----- Original Message -----
From: "Gareth B." <paul-clinco at mindspring.com>
To: <synth-diy at dropmix.xs4all.nl>
Sent: Saturday, March 19, 2005 11:11 AM
Subject: Re: [sdiy] AM reciver


> >>does anyone know much about building a AM reciver ? i was thinking
> >>that it would be a intresting "noise source" and random sound
> >>generater
>
> > You do realize that you can probably buy one for far less money than the
> > parts would cost you? Unless you really want to learn how to create a
> > radio
> > from scratch, it would be much easier and cheaper to purchase an
> > inexpensive one, and then modify it to suit your needs.
>
> Ocean State Electronics, a mail-order supplier of hobby electronic items
> (120 page catalog) offers several single chips which contain complete
> radios; also a few semiconductor receiver kits from Ramsey (broadcast band
> AM and FM, aircraft band, shortwave, ham...)
>
> All-American Five tube radios are reasonably plentiful at yard sales. I
> found one for $15, improved it greatly by replacing one power supply cap.
>
> If you're looking for higher quality and all-new homebrew, there was a
> multipart article in AudioXpress on building a vacuum tube radio.
>
> But if it's just noise you want, ebay often has General Radio Noise
> Generators for less than $30, if bulky black-wrinkle finish electronic
> dinosaurs are your thing, perfect for Mad Scientist arrays of strange
> creations.
>
> -- Paul
>