Hi,
I had such a problem recently on my SDR part, the one that drives the waterfall. Problem is divided into two distortions, some are narrowband spurs, others a wideband noise that adds to the reception.
In order to find the causes I finally ran those components necessary from a battery (23cm transverter, FT847 and PC) and removed power for the house at all.
Then I found: -> Ground loops: Transceiver and PC must be connected to the same mains connector! -> IQ mixer is now running from a 8V LiIon battery (R2Hobbies) -> I removed the external oscillator that works as an LO for the IQ mixer and use a simple 1.8432 computer oscillator there.
I also found that the 3-phase-inverters that I am using for the dish drive have internal CPUs which unfortunately generate a strong spur on 144.016 and 144.020. I tried to pull them downwards but they are that awfully accessible located in the inverters so I had to give up.
-> I put 5-turn-ferrit cores on each line that goes into the inverters
It really solved all problems despite the spurs of the inverter CPUs which now are little bit weaker but maybe I have to mount these two units into a screened box.
73, Günter (dl4mea)
I am using and LVB tracker to control my GS5400B AZ/EL system. I mainly use it on EME and WSJT controlling it with NOVA. There has always been excessive noise shown on the waterfall when I am on certain 144mhz frequencies. I can cut power to the 5400 and it goes away so I am pretty sure it is either the box itself or the USB connection. I have put toroids on the cable ends. I have also tried different computers and it is the same. Any ideas on what I could do to remedy this. I can cut power to the rotor and all is fine. But the I have to restart NOVA each time. I could live with it if I could just switch the Rotor control off and on without restarted NOVA etc..
Thanks Joe KI4TZ
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