PSR-500 Discriminator

N9JIG · #1 (**permalink**) 10-27-2007, 8:21 AM

I bit the bullet and opened my PSR-500 and found the Discriminator. Being a GRE radio I took a wild guess and tried looking for a "TP-4" and sure enough, there it was on the main board an inch below the volume/squelch control.

I connected this to a CD-1 PL decoder and a data slicer and it worked as well as other radios for decoding PL, DPL, DTMF and 3600 baud trunked control channels.

To access this remove the four screws on the rear case after removing the battery and battery door. You may wish to use a pigtail type jack connection or try to mount a jack on the radio someplace.

Standard disclaimers: Your radio, your risk etc. This will probably void your warranty. Your mileage may vary. Void where prohibited or taxed and in Vermont. Winner responsible for taxes and fees.

KD4YGG · #2 (**permalink**) 10-27-2007, 4:52 PM

Rich

Congrats on the first voided warranty (Heh! Heh!)

Actually thanks for posting the information.

DickH · #3 (**permalink**) 10-27-2007, 5:43 PM

Quote:

Originally Posted by KD4YGG

Rich
Congrats on the first voided warranty (Heh! Heh!)
Actually thanks for posting the information.

Didn't I read in one of these threads that a Discriminator Tap is a built in feature of the PSR500?

WayneH · #4 (**permalink**) 10-27-2007, 6:14 PM

Quote:

Originally Posted by DickH

Didn't I read in one of these threads that a Discriminator Tap is a built in feature of the PSR500?

It only outputs the formatted data messages sent out by the trunking formats which the scanner understands. These would include APCO-25 Trunking ("Motorola 9600"), Motorola 3600, EDACS, and LTR.

So no MPT, PassPort (damn IP), ATCS, paging, etc that others find of interest besides the big name formats.

ScanManQSL · #5 (**permalink**) 10-27-2007, 10:11 PM

Quote:

Originally Posted by KD4YGG

Congrats on the first voided warranty (Heh! Heh!).

N9JIG, Thank you for taking a bite out of your warranty just to share the useful information with all of us on RR. My first thought when seeing this picture was I cant believe you opened up your brand new $500 scanner!!!

Thank You!

mkewman · #6 (**permalink**) 10-28-2007, 12:37 PM

huzza! you've got some cajones on you brother!

kikito · #7 (**permalink**) 10-29-2007, 2:07 PM

Quote:

Originally Posted by mkewman

huzza! you've got some cajones on you brother!

Are you saying he's got some "big boxes" (cajones)? Or you mean "cojones", big bull balls?

KSJ745 · #8 (**permalink**) 10-29-2007, 2:25 PM

That's WILD! Soooo COOL too!

Happy Scanning!

TexScan780D · #9 (**permalink**) 10-29-2007, 7:37 PM

What software will one be able to run with the PSR-500 Discriminator?

N9JIG · #10 (**permalink**) 10-29-2007, 8:07 PM

Quote:

Originally Posted by TexScan780D

What software will one be able to run with the PSR-500 Discriminator?

There are a lot of programs that require or at least prefer discriminator audio. These include many variations of Trunker, Treport, Trunk88, as well as ATCS Monitor, and many other programs that decode a variety of digital signals.

rchalupajr · #11 (**permalink**) 10-29-2007, 8:12 PM

Rich, are you going to do the tap?

mancow · #12 (**permalink**) 10-29-2007, 8:18 PM

By the way,

I already cracked mine open for other reasons.

While I was in there I put a small piece of white plastic on th e tri color LED with some duble sided tape. It made the light usable in a dark environment without blinding you even on a lower setting. It seemed to make the colors more true too since they seemed to mix in the white plastic. The color is more even, sort of like a flourescent light.

N9JIG · #13 (**permalink**) 10-29-2007, 8:42 PM

Quote:

Originally Posted by rchalupajr

Rich, are you going to do the tap?

Probably not, at least not now. I have a pair of PRO83's that I have taps on for the few times I need a portable with discriminator audio. Better a $60 radio for this than a $500 one.

I do have most of my mobile/base radios tapped, I use them all the time with various decoders.

tojohnso · #14 (**permalink**) 02-27-2010, 2:51 PM

This is a really old post, but I found it using a Google search. If you're still around, I'm curious why you did that when you could use the data port and USB cable?

Will the GRE, Uniden, and RadioShack radios with data port work with UniTrunker?
A: With the GRE PSR-500 and PSR-600 as well as the Radio Shack Pro-106 and Pro-197 you do not need a discriminator tap; the program reads through a USB cable attached to the radios' PC/IF data port. UniTrunker has support for EDACS, Motorola and P25 systems with the GRE PSR500/600, RadioShack Pro-106/197, and Uniden

N9JIG · #15 (**permalink**) 02-27-2010, 4:16 PM

That's great if you are running applications that support that data format. I often need straight discriminator audio for things like data decoders (ATCS, trunked, etc.) or specialized PL/DPL decoders.

Since all my tapped radios are set up the same way, it is real convenient for me to do it this way.

tojohnso · #16 (**permalink**) 02-27-2010, 7:08 PM

I see. Thanks!

mainetrunk · #17 (**permalink**) 12-13-2012, 9:08 AM

This post may be 2 years old, I just got here. Now, you are saying to open my pro 106 and?-- simple english please. Bottom line I wanna scan Mototrbo. I got soooo many mixed answers. Tell me your way is best.

DickH · #18 (**permalink**) 12-13-2012, 10:03 AM

Quote:

Originally Posted by mainetrunk

This post may be 2 years old, I just got here. Now, you are saying to open my pro 106 and?-- simple english please. Bottom line I wanna scan Mototrbo. I got soooo many mixed answers. Tell me your way is best.

You need a discriminator tap to get up the raw (unfiltered) audio. You feed that into your computer, then get a program called DSD?. I believe that is the only way you can hear MOTOTRBO.
Rather than tie up your PRO-106, just get an old 800MHz capable scanner and install a discriminator tap and put it on the control channel freq.
Search around this site for more info.

mainetrunk · #19 (**permalink**) 12-13-2012, 10:11 AM

I been looking, searching-but the question is unanswered-where to get a tap. Got a chance to get 1 from the Netherlands-installed. I am desparately looking for 1, but around here-who what? Technology gets to Maine LAST. Kinda good, but need to be in the present. WHERE to get 1?

Spitfire8520 · #20 (**permalink**) 12-13-2012, 10:26 AM

Quote:

Originally Posted by mainetrunk

I been looking, searching-but the question is unanswered-where to get a tap. Got a chance to get 1 from the Netherlands-installed. I am desparately looking for 1, but around here-who what? Technology gets to Maine LAST. Kinda good, but need to be in the present. WHERE to get 1?

You make it yourself with with a resistor, capacitor, solder, and a small perf board. If you're bad with electrical stuff, you can alternatively look around for a radio shop or something and pay them to do it for you.

Pro-106 Discriminator Tap - The RadioReference Wiki