Proximity to computer

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KeyboardKid56
Posts: 1
Joined: Tue May 23, 2017 9:21 am

Proximity to computer

Postby KeyboardKid56 » Tue May 23, 2017 9:29 am

How close can the SDRplay2 be positioned to the computer being used? I do not want to cause undo interference to reception by proximity to desk top computer. Had anyone had any troubles with this happening?
Thanks
Last edited by KeyboardKid56 on Thu Jan 01, 1970 12:00 am, edited 0 times in total.
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DanubeBCL
Posts: 160
Joined: Sat Jul 02, 2016 12:39 pm

Re: Proximity to computer

Postby DanubeBCL » Wed May 24, 2017 6:25 am

Computers in the vicinity of receivers always can cause trouble. Make sure that the antenna is as far away from the house as possible and insert a common mode choke directly at the antenna input of the receiver to block common mode noise induced into the coaxial cable by switching power supplies and all that stuff. Connect your PC case to a good ground. It might also be necessary to apply extra shielding to the receiver, to add power line filters to the computer/monitor, to wind the USB cable several times through a wideband toroid of high permeability and additionally use a galvanic isolator in the antenna cable at the receiver when ground loops are the cause of noise.
It is often not easy to find out which countermeasures are required and which are obsolete. You must try out which solution(s) help most in your individual environment. Avoid placing the receiver directly on top of the monitor or a switched power supply, even when the RX has a shielded case. These devices can create strong magnetic fields which penetrate the (mostly aluminium) shielding. You can easily find out this by moving the RX closer to the PC/monitor/power supply and watch the spectrum/waterfall. When spikes and spurs appear, you are too close. But the space between the PC and the RX is not the only criteria. All the wiring from and to the receiver plays a big role, too.

73, Heinrich

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W2DLC
Posts: 40
Joined: Tue Apr 04, 2017 1:51 pm

Re: Proximity to computer

Postby W2DLC » Wed May 24, 2017 2:46 pm

It also depends on the construction of the computer. I'm getting a spike every 17KHz that comes from my computer. It gets worse when I disconnect the power supply, and it seems to be coming through the antenna line because it goes away completely when I disconnect the antenna. I can significantly reduce it by grounding the receiver's case, but it doesn't go away completely.
That's with a cheap HP laptop which has a plastic shell and the USB ports seem to be a little loose. When I use my ASUS tablet, there is no interference.
(Edit) As it turns out, it's not the computer that's causing the interference, but two powers supplies. My 13.8 volt switching supply is causing the spikes, and the HP laptop supply is causing a general wideband increase in noise level 0f 4-6 S units when it's plugged in.

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