Thursday, January 13, 2011

Icom PCR-100 IF output mod

I acquired a USRP N210 in December and love it. I was using an old Pro-2022 as my IF but it has alot of freq gaps, cant be controlled with the pc, plus other issues.

So I bought a PCR-100 off eBay for cheap and proceeded to read the service manual for it which can easily be found online. The service manual labels the parts really well, although my pcb rev is slightly different then the one in the manual its close enough.

I chose a spot right after the 2nd IF, right past a cap. Your going to need a cap anyways to filter the DC out, plus it had a through hole to make it easy to solder a wire too. (I see now recommends the same spot hehe)

Now if your only interested in 230khz of bandwidth (ie a softrock which has 192khz bw) then you may want to consider choosing farther down the line. Past the point I chose it goes to a NBFM or WBFM filter, then to another IF amp. You may want to choose that IF amp as a tap point, but I wanted alot more bw then that, I wanted to get as much as I possibly could from the Icom unit. Plus Ive got a IF buffer amp from Clifton Labs I will be eventually putting inline, so the extra gain isnt that important to me.

I took pictures as I went along, you can download them in high res here

As a note, I use qpcr1k in linux to control the PCR-100, which works well over X11 forwarding so my mac has access to it as well. I use gnuradio companion (grc) for the USRP N210. That USRP w/Gnuradio is an amazing combination, one heck of a SDR.

edit: 05 March 2011
Ive uploaded my Simple PCR app, all it does it turn the device on/off and tune a freq
edit the .py file to set your /dev/ttyUSB# or /dev/ttyS# your using to connect the computer to the pcr with


  1. Hello, it seems I can do some switching from the pcr command, but when I use the same options with the qpcr1k command, the program seems stuck on /dev/pcr1000 instead of /dev/ttyUSB0 for me (USB to serial converter). Did you modify any file so that it works in your configuration? Thanks. Sebastien.

  2. qpcr1k is just a Python app so its easy to edit in a text editor. You could also use ln -s to create a symbolic link from /dev/pcr1000 to whatever actual node you want.

    if all you want todo is set the freq I wrote a simple python app todo that.

    I'll edit my orig post and past the link

  3. It was actually me that updated the RadioReference Wiki, but I hadn't seen your blog at that point ;)

    I looked at the service manual and thought 'hey, there's a cap already in the signal path and a nice hole to solder to'.

    My question is, does your PCR-100 have a very low IF output? Mine is barely discernible sometimes. It also is quite 'noisy' with lots of 'spurs' and spurious signals.

    David aka Napalm.