Re: 49Mhz to 6Meters conversion?

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From: Daniel C Winkler (dwink@juno.com)
Date: Mon Jul 14 1997 - 09:07:19 EDT


Hi Gang,

>Radio Shack ...selling a 49Mhz walkie-talkie for about $5.
>... any plans fo modifying these to work on 6 meters?
>... cw built-in...

I don't think these are the same units Dana spoke of in his
post (7-9-97) ...(YES, I am that far behind on my mail!).

I have a pair of similar units from RS from a year ago.
ARCHER SPACE PATROL Model No 60-4020
I got curious, so I just now took one apart.

Plastic case 6 x 2.5 x 1.5 inches w/ 9v battery compartment...
case held together by single screw and a little gum (really).
Well, there are little plastic fingers to help.
PC board held in place by another single screw. Speaker is
glued in. Antenna is a 9" ducky... looks like it is a 9" length
of door spring with shrink wrap over most of it!

There are:
  3 transistors
 1 transformer
 3 switches (sorta...if you count a piece of tin can bent up over but not
quite
touching a longish rivet a switch!)(that's the "key")
 13 resistors
  8 ceramic capacitors
  3 electrolytics
  2 coils (To quote one of the masters {the good Rev.}{you gotta read
this
with a British accent!} "...look inside the radio, and if it has a lot
of coils, then
you know it is a good radio.")
  1 crystal
  1 pc board 3.5 x 2 inches, with .75 inch hole in it (for speaker)

These things are AM modulated crystal oscillators. The receiver is a
super-regen, and you wouldn't believe the RUSH it gives out on
receive. There is no volume control, only on/off. The "cw"
is mcw, achieved by introducing feedback into the audio amp.

THERE IS NO MICROCOMPUTER IN THIS RADIO!!!

It is about as minimalist as you can get and be voice. It
does work. Range abt 1/4 mile (I can shout as far).

I, too, bought them with 6m conversion in mind, but after looking
them over, I decided it would be better to start from scratch.

However, look at it another way. For $5 you get a door spring.
And an ok case with battery compartment. And a little speaker
built in (VERY built in). And a crystal (49.860). And a transformer.
The rest of the parts are probably not worth saving.

So you could keep the crystal and use it for the XO for a superhet
(it's an overtone xtal, so it won't warp much- not much of a VXO-
you are stuck on one frequency!) with a 455 kHz IF (use one of those
Murrata ceramic filters from Digikey or Mouser)- puts you at 50.315.
Buy a crystal for 50.315. (About $15) Run AM (you are above 50.1,
so anything goes, as far as FCC is concerned...)

With a little work you could stuff it all back into that case...

A lotta work for little return, I think. But the parts are probably
worth close to that $5 price, *if* you can use them.

Dan Winkler N7IVR Seattle WA


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