SC150Y Discriminator Tap Mod

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madonion

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I can see my self putting a ceramic condensator to block the DC. But I dont see why you would put a resistor. What pin did he tap on the IC ?
 

K4OC

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matthoward said:
I've had a few requests for pictures of the disc tap on my Uniden SC150Y, so here they are: Let me know if you have any questions.

Not sure where you tapped. Did you go on the underside and tap instead of tapping off the leg of the IC? I tapped mine but I think I separated the board and got access to the other side and tapped there. I used hot glue to provide strain relief. If I get my time I will post my pictures too.
I use my SC150y for the 868.7875 source for UniTrunker and T4WIN. I run them both.

The only thing I might do later is go back inside and couple the tap to the discriminator output via a capacitor. I did not have the correct type laying around at 2am when I performed my modification.

I'll keep in touch. Thanks for posting.


Sam Cederas
K4OC
Raleigh, N.C.
442.075
 

mhoward785

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madonion said:
Could you do a brief description of what you did please ? I have the same scanner.
I pretty much followed these directions for a BC245XLT:
http://www.discriminator.nl/ubc245xlt/index-en.html

slicerwizard said:
It looks like he did a direct connection tap - no isolation resistor, no DC blocking cap. Not a good idea. Kids, don't try this at home.
I'm no electronics expert. It works fine as is. Could you explain why I should not have done it the way I did? I'm not that concerned about damage to the scanner. I was about to trash it because everything in my area is trunked, but then I realized I could still use it for the disc tap.
madonion said:
What pin did he tap on the IC ?
I'm not sure how else to describe it other than if your looking at the chip (or "IC"?) with it oriented so you can read the markings I taped the top-right pin.
 

Airdorn

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slicerwizard said:
It looks like he did a direct connection tap - no isolation resistor, no DC blocking cap. Not a good idea. Kids, don't try this at home.
Could someone explain this instead of just poo-pooing it? I'd be interested to know why a cap and resistor is needed.

Thanks!
 
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