I bought a KX3 and PX3 with a view towards using them with an external high performance transverter for 144MHz (with an IF of 14MHz). My main interest being weak signal operation on VHF. The ability to use the I/Q outputs with a sound card or PX3 and the excellent receiver performance in reviews seemed to indicate this would meet my needs.
Unfortunately it looks like this is not going to work out for me, as the level of radiated noise at VHF from both the PX3 severely masks weak signals, there is also a huge radiated birdie from the KX3 near 144.4MHz. Turning on the PX3 and listening on 144MHz gives bands of noise every few kHz which mask weak signals in the noise and I can liken it to listening to the 6m band with a Band 1 TV transmitter putting out video sidebands over the band. Without the PX3 switched on I can hear distant beacons in the noise, but they are buried by the PX3 when it is switched on and plugged in to the KX3. The antenna is 60 feet away from the rigs and is fed by Heliax. Have tried separate supplies for transverter and PX3, running from batteries on KX3, nothing seems to reduce the QRM from the PX3 to an acceptable level. There also is a huge S9 spurious near 144.4 from the KX3 that is independent of band/freq/mode. Confirmed by listening on another receiver in the shack. It is so hugely disappointing, I had looked forward to this day, having finally got my rotator and antenna back up on the tower I am faced with looking for another rig to drive the 2m transverter. Unfortunately I don't think it will be Elecraft. Perhaps Elad might be an alternative, but I need to consult the weak signal VHF community first. I will keep the KX3 and PX3 for QRP HF work most likely as selling it at a loss would be a bitter alternative. On HF where the band noise and signal strengths are much higher I don't find the same problems, though there are still spurious signals shown on the PX3 there. I could live with them I think, but on what is a nice quiet 144MHz band here, the racket from the PX3 is impossible to put up with. Incidentally I wonder what causes that big birdie near 144.4 from the KX3, and if is it related to the similar one reported on the K3? There doesn't seem to be a lot of commonality between the designs. Sorry if this sounds like I am trolling, I am not, I love the Elecraft ethos and products, it is just they don't appear to work for my specific needs. Unfortunately it wasn't possible to try before you buy here and I ended up being the guinea pig. 73 David Anderson GM4JJJ ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
