[comp.dcom.telecom] Scanner Diodes, etc

NJS@ibm.com (Nicholas J. Simicich) (08/20/90)

 From: TELECOM Moderator <telecom%eecs.nwu.edu>

>  I beleive it is illegal in and of itself to make the mods in a radio
>  simply because having done so, the radio loses its type acceptance
>  from the FCC, and radios without type acceptance cannot be used.

>  All radios, even those that 'only' receive, such as scanners, still
>  none the less also transmit, even just a little, using the
>  intermediate frequency. That's why no mods are allowed, since you
>  could, if you know not what you are doing, cause the radio to transmit
>  in an inappropriate way ... even a scanner.

My belief is that one is allowed to build receivers without government
type acceptance.  I know that all radios that receive using a
superhetrodyne circuit also transmit (radar detectors, for example)
but I don't think that the emissions are considered to be "enough" to
matter.  I believe this, partially, because you can commercially
purchase receiver kits and build them without any sort of permission
or warnings against modification.

>  You take a diode from one place, and set it in another place. To
>  merely remove it is not enough (I don't think). You have to replant it
>  elsewhere to do the job, and in so doing, you lose 30-50.

There is a ftp site which maintains a list of mods for radio
equipment, scanners, etc.  A friend of mine pulled the Pro 34 mod for
me.  I've reproduced this file at the end of the note.  I believe that
it does indicate that you remove the diode, and throw it away.  If you
are interested in the name of the site, I've copied him on the note.
Respond, and I'm sure that he will be happy to tell you the name of
the site and give you FTP instructions.

>  I might be wrong on that, but to prove it, I'd need to open the unit
>  again, and pull the diode from where it is now and see if 800 still
>  was open in the process along with 30-50. Anyway, 30-50 is pretty much
>  a dead issue around here (most other places also?). No one is down
>  there to speak of.

Around here, all of the local Fire Departments are down around 39 Mz
or so.  VHF Low is alive and kicking in NY.  There is also some County
Sheriff activity in VHF Low.


Nick Simicich (NJS at WATSON, njs@ibm.com) ---SSI AOWI #3958


  Date: 4 Apr 89 14:24:01 GMT
  Subject: PRO-34 Scanner Modifications


    In  the  May 1989  edition  of  Popular  Communications  is a
"Letter  to the Editor" on the Radio Shack PRO-34 Scanner.  Below
is the text of that letter.


                  PRO-34 Scanner Modification

    In regard to the information  presented (March Issue)  on the
handheld Radio Shack PRO-34 scanner,  my own observations  on the
modifications have been:

1. To restore missing 800 MHz frequencies, remove D-11.

2. To add 66 to 88 MHz  (European Coverage),  install a diode at
   D-9.

3. D-10 must remain in place for full 800 MHz coverage.

4. If a diode is added at D-13 it cuts out aero band, also seems
   to affect 800 MHz channel spacing.

5. D-12 added dosen't seem to have any affect.

6. Only D-10 and D-11 are factory installed.

    I  wish to thank you  for a fine and informative  magazine. I
have had much reading enjoyment.

                             Sam S. Jones,
                             Rebel Antenna,
                             Falls Church, VA


Julian Macassey, n6are  julian@bongo    ucla-an!denwa!bongo!julian
n6are@wb6ymh (Packet Radio) n6are.ampr.org [44.16.0.81] voice (213) 653-4495