Pro-43 discriminator tap

[manross]

I've searched the site and the web for a picture of the discriminator tap point for a Pro-43. Does anyone have a pic that they can post or send me?? Thanks in advance.

Marty

 

[slicerwizard]

Photo here:

http://home.ica.net/~phoenix/wap/Pro-43/Pro-43 Discriminator Tap.jpg

The tap point is the pad on the audio board with the white circle around it. It's right next to the black five pin connector that runs between the RF and AF boards. It normally has a metal test lead soldered in place, but I removed it to make room for the 20k resistor that you see in the photo. The signal runs through the resistor and the 10uF tantalum cap to the outside world. You can use any convenient ground point, even under one of the silver screw heads.

You can try to do the work without removing the RF board, or if it's too tight, you'll have to remove the six screws plus the PLL cables and the BNC connections to get the RF board out of the way.

 

[manross]

Fantastic. That is absolutely perfect. Just what I needed. I already have the board off so getting to it is a piece of cake. I just wanted to make sure I was getting the right place.

If this board supported "Reputation Points" you would surely get some Thanks again.

Marty

 

[slicerwizard]

Sounds like you're in great shape. The 43 is a decent data workhorse; mine has been doing the job for close to ten years now.

 

[FrankJ]

Yes, I still use mine daily for UHF and VHF milair with a Diamond RH77CA antenna.

Frank

 

[slicerwizard]

I meant as a discriminator audio source, but yes, they seem to take abuse (mine have been dropped a few times) and just keep on working.

 

[manross]

That's funny about the Pro-43. Before my city went to APCO 25 the Pro-43 and the Realistic 1600 mobile was my listening equipment. The poor things sat out in my unheated garage for a couple of years on my work bench getting shuffled around and buried under god knows what. When I started to investigate getting into MilAir monitoring, I fired them both up and they worked perfect. I would never have thought that I'd be using old technology to enjoy new technology Now I need to find a use for the 1600....

Marty