I know this is going to be obvious to a majority of this list but I have finally figured out the VERY simple cure after dealing with it for 10 years and I thought I'd share it in case it might save someone else some grief with SO2R or multiple rigs feeding one headset. I am a far cry from being an electrical engineer so this description is written at a basic level...the only one I have.
I operate exclusively in SO2R mode so I always have two K3s connected. My transmitted audio and CW notes were always fine in SO2R but my headset was getting a loud thumping noise on CW (all power levels) and garbage on SSB in all the configurations I've had over the last 10 years (pair of IC-765s, K2s and now K3s using both commercial and homebrew SO2R boxes). I originally thought I had an RF interference issue but many useless ferrite beads later told me that was the wrong answer. My next attempt was looking at ground loops. W0YK and W8JI have excellent web pages with suggestions to fix various transmitting issues but I didn't have those problems, mine was only on receive when two rigs were tied together, however, W8JI had a box which allowed his headphones to be switched to multiple rigs and he had audio isolation transformers in the headphone circuit for each rig. I bought the same isolation transformers he mentioned and used them in the K3's back panel headphone jack to feed my SO2R box. Eureka, problem solved! I have since purchased a pair of "Cables To Go 40000 3.5mm Extension Stereo Audio Isolation Transformers" (Amazon ~$30US) since they were neater than my home brew concoction and specifically made for headphones. I used this new arrangement in the NAQP CW contest last weekend and it was SO nice to clearly hear my alternate rig while I was transmitting on the other rig. It improved my score significantly. So, if you are trying to solve a similar issue, this idea might save you lots of wasted effort. Bob K5WA ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
