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HDSDR2 Waterfall screen noise with RSP2

Posted: Sat Oct 14, 2017 5:44 am
by K4ZOT
Hi - new member here. Been using the RSP2 for a few weeks with HDSDR2 and I 'm very impressed with it on my TS-590SG. I have one problem with the unit - apparent electric line noise appearing as thick lines every 60 KHz. I am using RG-213/U coax cable. My RSP2 USB cable to the PC has RF chokes on the line as well as the 590 DRV input coax cable to the RSP2. Switching antennas has no affect - must be getting into the lines in the shack - all equipment is grounded. I would assume that RF magnetic ferrite chokes on the coax cables should be installed next. Just curious if any one else has had the problem with apparent electric line interference showing up on the waterfall display. Any comments appreciated.

Thanks,

Glenn
K4ZOT

Re: HDSDR2 Waterfall screen noise with RSP2

Posted: Sat Oct 14, 2017 3:22 pm
by DF1KZ
Hello Glenn,

Welcome to the world of EMC.
Many devices especially those cheap ones coming from Asia do not fulfil the requirements of the EMC-directive (Europe) or FCC (USA). They produce to much noise on the power-lines, the power-lines radiate this noise and you hear the harmonics of the switching-frequency of your (or your neighbours) power-supply.
An other version of these noise-generator is called PLC (Power Line Communication). PLC misuses the power lines for data communication and because power lines are not made for data communication they radiate the PLC signal.

You did not say which frequency range is disturbed but I assume its LF and MF and maybe SW. At first try to switch off (better: unplug) all devices and look whether the noise disappears. The worst noise producer I ever had was a small (5V,1A) power supply of a network switch.
If that doesn't work start a "Fox Hunt" with an AM-receiver and a ferrite antenna. The noise does not need to come out of your house, maybe its your neighbour.

Ferrite cores or chokes do not work good on low frequencies (LF, MF) their inductivity is to low.

Good luck!
Wolfgang (DF1KZ)

Re: HDSDR2 Waterfall screen noise with RSP2

Posted: Tue Nov 14, 2017 3:50 am
by K4ZOT
OK - thanks very much. Is there a way of filtering out some of the screen noise with RSP2?

Re: HDSDR2 Waterfall screen noise with RSP2

Posted: Tue Nov 14, 2017 2:28 pm
by DanubeBCL
K4ZOT wrote:OK - thanks very much. Is there a way of filtering out some of the screen noise with RSP2?
That depends on how the noise comes into your receiver. Some of the countermeasures have already been mentioned.
1. Good grounding of receiver and coaxial cable shield
2. Common mode chokes at the antenna input of the receiver (no snap on ferrites, but large wideband toroids)
3. Line filters for computers, monitors, switched power supplies in the house
4. Winding USB cables through large toroids
5. Bigger distance between antenna and noise sources
It is difficult to predict which countermeasures help unless the cause of the noise is clear. It can be a sort of magnetic induction into the coaxial cable or direct catch by the antenna. 60 kHz spacing is an indicator for switched power supplies in the vicinity. Item 2. should help when the noise is induced into the coax cable, but is not present in the antenna. Additionally item 3. should help when your own computers, monitors or other devices in the house create the noise. Everything is useless when the noise is picked up by the antenna itself from your neighbourhood.
73, Heinrich

Re: HDSDR2 Waterfall screen noise with RSP2

Posted: Tue Nov 14, 2017 9:04 pm
by K4ZOT
I checked out various noise sources in the house and found a replacement laptop PS that was causing all the noise on the SDRuno. The displays are perfect now and great to use.

Thanks,

Glenn