Wednesday, 11 May 2011

Kenwood R2000 - SDR panadaptor updates

Well dear readers, after struggling with my IF tap and the SDR loading the circuit too much, I built myself a buffer amplifier.  It consists of a 2N3819 JFET and a regular transistor in emitter-follower mode.  It works nicely, and plugging the SDR into the R2000 has no effect. 

I was having a few issues with the SDR receiving stations directly to its own front end, due to the LO being tuned to 9.850MHz.  I had a look around there with the SDR and no R2000 connected and can see a load of broadcast stations.  The reason I chose 9.850 is because if tuned to say, 5500kHz on the Kenwood, the display on the PC via the SDR lined up nicely with the band I was looking at.  I could see Shannon volmet at 5505, Shanwick at 5598, etc. etc.

Anyway, the broadcast breakthrough was annoying me, so I searched around and found a clear spot of spectrum at 10MHz.  10050 to be exact.  The SDR only sees two weak carriers which when connected to the IF of the R2000 disappear totally.  It just means in order for me to know what frequency I am on I have to subtract 200kHz from the display on the R2000.  Not ideal but what can I do - the Kenwood isn't PC controlled.

I've reboxed the Cross Country Wireless SDR in a plastic (yes, plastic case) as the ex-MoD equipment case I had the thing in before was too heavy and cumbersome.  It was shielded, sure but it was getting in the way.  I now have it mounted in an old Atari external disk drive case (pics soon) and once given a coat of black paint will fit in nicely with all the other 'black boxes' in my shack.  The plastic case also lets me easily transport the radio with me - the plan eventually is to pick up a cheap (but good quality) external sound card so I can just pitch up somewhere with netbook + SDR and have at it.

Next thing to do is to attempt to tap my PCR-1000, but as funds are limited in this day and age, I don't fancy risking it.... yet, anyway!

1 comment:

Ranger Ricky said...

Found your post via Google search. I have an old Heath SB-1400 that I would like to update by attaching an SDR to the 2nd IF around 9mhz. Could you please display the isolation circuit you used so I can 'borrow' it?

Rick K3IND