Ok, people keep asking me how, so I finally resolved to overcome my laziness
and to post this file once for all. As with the preceding ones, standard
disclaimers, I take no responsibility, I like to hear comments, etc.
I've been reported that this works with pocsag and symilar decoders, anyway
(There is not much where you can fail in soldering one wire on a pcb). So:
**************************************************************************
* Direct (unfiltered) FM discriminator out for the AR3000/A scanner *
**************************************************************************
Several firmas offer this mod routinely, and it is not difficult.
AOR-UK gives instruction for doing it yourself. They reccommend to bring
the signal to pin 1 of the backpanel DIN connector; I think that should be
standard.
-> pinning of the din is:
2
4 5
1 8 3
6 7
The discriminator out is found on pin 9 of IC1 of the main/if/af board (the
lowermost of the scanner). It carries an unfiltered output in N/WFM modes,
I'm not sure if it gives still a (bandwidth limited) NFM when the scanner
is in other receiving modes.
All the mod is to solder a piece of wire from that pin to the DIN8. For
extra protection, I added a 0.2 uF capacitor inbetween.
The IC is easily identifiable once the board is unscrewed and turned upside
down. There are few smd ics on that side of the board; IC1 is the only '3357'
and is located more or less on the opposite side of C70 - L28 - L29 - X4 etc.
If you're too lazy to unscrew the board, as I was, the signal track is also
available on the upper side. Here is how to find it:
/---\
/ VR3 \
\ /
\---/
..........._,
: XF2 : #
: :
..........:
the wire has to be soldered to the point #.
Enrico Segre,
[email protected]
