Discriminator Tap Plans/Diagram Question

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fourthhorseman

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hey all!

im getting ready to tap my 106,
so im dotting my I's and crossing
my T's..

just freshining up on the job and ive
had a question now for a while..


ive seen 4 diff styles of taps made,

1 comprised of
2 resistors,1 tant capacitor,
another,
1 resistor,1 tant capacitor
and another,
1 resistor,
and...
1 tant capacitor


so i ask,,
whats the consensus?
 
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fourthhorseman

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Never had a warranty,
besides,,i think the LED-LCD mod that i performed would
have surely achieved that already.(and for the record,
That was a hard mod,,once you cut out the lil amber SMT
LEDs..you get that,,ugghh,,thats permanent!..and tiny
too..just my eyeballs to do the connects...)
...
not runnin unitrunk,,can run that off my PC-IF

need the info on the tap only.

thanks though..4th...

Sheesh,,why's everyone so hung up
on voidin the paperwork,,,lol...
 
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VE3RADIO

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The resistors and values of the resistors basically tune the output quality, you can do it with one or two .. i know for a fact mine is done with two resistors and has an amazing decode rate for Trunk88! A very wise person gave me a very detailed lesson on good taps vs bad taps.. unfortunately I am nowhere near smart enough to try and re-explain in anywhere near the details he did.
 

DickH

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... Sheesh,,why's everyone so hung up
on voidin the paperwork,,,lol...
That wouldn't be my hangup either. But why tie up your 106 when any old 800MHz capable scanner will be easier to tap?
Also, Trunk88 does not require a disc. tap and does all sorts of things.
 

fourthhorseman

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doing the 106 because its my travel radio..i like to have a reciever that can get full spectrum RX when in areas that im not sure whats out there TX'n!


WZ1,,
you happen to remember the values of the rez's..or the config?..
were they 10k and 47k's?
 

fourthhorseman

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yeah it would,
the question though Isnt how to tap,

its regarding that Actual tap,the make up of the resist's/cap's

the process is a breeze as stated above,looking for thought on the
tap itself..
 

slicerwizard

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ive seen 4 diff styles of taps made,

1 comprised of
2 resistors,1 tant capacitor,
That's how it's supposed to be done.


another,
1 resistor,1 tant capacitor
Only suitable for driving a data slicer.


and another,
1 resistor,
No DC blocker. Only suitable for driving a data slicer that has its own DC blocker.


and...
1 tant capacitor
Garbage. Provides no isolation for the scanner's discriminator circuit.


so i ask,,
whats the consensus?
You're driving a PC sound input, so the capacitor is a good idea to isolate the DC voltage (~1.5V) on the discriminator circuit from the DC voltage (~2.5V) found on mic inputs.

A 600 ohm line input puts an excessive load on a discriminator circuit, so that's generally out. That leaves you with a mic input, which won't tolerate a direct feed from a discriminator, hence the two resistor voltage divider. Some sound devices, like the cheap "3D SOUND" USB adapters, tend to distort waveforms if you feed them a too-high impedance signal; they seem to like a 27k-5k divider.
 

Radioman96p71

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Originally Posted by fourthhorseman View Post
ive seen 4 diff styles of taps made,

1 comprised of
2 resistors,1 tant capacitor,
I want to build this inside my IC-R7100. Where can i find the schematic? I will try google again after a bit but wanted to see what the pros had to say :) TIA
 
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