Discriminator Tap Pro 2055

[gorak]

A few questions here....

1. What does a discriminator tap mod exactly allow me to do, lets say I want to buy a pro 2055. Would it allow me to plug it into my sound card in my computer and decode Digital trunking p-25 transmissions via my computer? If so what software is needed in order to do this?

2. How do I do it: are there any additional parts required, how hard is it?

 

[N1BHH]

Google finds you anything you want: http://www.linkerror.com/pro2055.cgi?lang=en

 

[loumaag]

Or you could just look on the RR Wiki for the answers to these basic questions.

 

[dcubed]

I've recently done this mod to my pro-2055, added the parts and image to the wiki
Pro-2055 - The RadioReference Wiki

 

[nosig55]

This an old thread but I want to revive and old pro 2055 with a discriminator tap. Can wires just be ran from the tp4/resistor & ground point to a 1/8" plug and not use a panel mount jack? So you end up with a wire stuck out the back of the radio.

How critical is the capacitor (.002uf) size? Can it vary and not be exact and then what is acceptable?
First time doing a D-tap, wanting to use DSD+

Any advice is welcome...

 

[slicerwizard]

This an old thread but I want to revive and old pro 2055 with a discriminator tap. Can wires just be ran from the tp4/resistor & ground point to a 1/8" plug and not use a panel mount jack? So you end up with a wire stuck out the back of the radio.

Yes, that's fine.

How critical is the capacitor (.002uf) size? Can it vary and not be exact and then what is acceptable?
First time doing a D-tap, wanting to use DSD+

A tiny cap like that will destroy all of the low frequency audio and you'll get very poor decoding. The 'net is full of instructions for data slicer taps that are near-useless for audio input taps. Use a 10uF cap to a voltage divider to your 1/8" plug.

 

[nosig55]

Thanks for the info.
The cap size came from post #4 above.
I'll give it a try and see what happens.

 

[jfhtm350]

What am I missing here?
The radio goes down to 25mHz. At 25000000 Hz and a 0.002 cap will add 3.1 ohms of resistance according to this page.
Resistance Frequency Capacitance Calculator

That doesnt sound that bad to me when your adding a 10,000 ohm resistor.
Im using a 10k ohm resistor with a 10uf cap in series on the positive wire.
Just curious to know.

 

[nosig55]

The D-tap on the pro-2055 is installed. I went with a 10k resistor to center of plug and a .01uf cap from 10k to ground. The cap was all I had or could find in the junk box.
I am able to decode a p25 system with very good decode.
Just started reading up on the DSD Plus and decided to use my old scanner on the shelf doing nothing. Very cool program. Still trying to figure it all out.