Re: Interference [1 Attachment]

Allan Isaacs

I see Doug has already replied to your noise spike problem Joe.

If you look on the following page you’ll see something similar to your problem

In this case the manufacturer used what’s called a “quasi-resonant” chopper chip and the extremely fast rise time of the pulses resulted in harmonics stretching well into the VHF band. The local ferry uses a particular marine channel and the problem interference was centred on it. In fact the particular circuit around the chip resulted in perfectly stable Q5 spikes. Whenever the ship’s restaurant dishwasher was turned on the same marine channel was blocked.

There are loads of interference sources resulting in a comb of spikes. Armed with a portable radio, I recently turned off our mains supply. The noise level instead of dropping shot up because the computer UPS unit came on. Here in the UK we have 230V mains and the DC supply in the chopper PSUs is around 360. 3 phase mains are at 415 to 440V and things like lift motor power supplies use a DC voltage in their PSUs of around 600V.

Your solar power brigade may well generate 3 phase mains, but at least its voltage is only half of that in the UK.

You would need to take the offending equipment apart and fit extra filtering and ferrite chokes.

I doubt very much whether you can get the interference reduced because most of these equipments are certificated to comply with blah blah FCC recommendations so your best bet may be to move house or rig up a small loop receiving aerial positioned to null out the worst spikes.

Allan G3PIY

From: sdr-radio-com@... [mailto:sdr-radio-com@...]
Sent: 06 November 2016 21:59
To: sdr-radio-com@...
Subject: [sdr-radio-com] Interference [1 Attachment]




I know this is not a console related post but you guys are really knowledgeable and I wanted to show you this. The 20 meter band has really been active for me lately but there is so much interference and spikes. I live near solar power owners and I'm running my RTL-SDR dongle through an up-converter running on a raspberry pi. I connect to the dongle via tcp from a laptop or PC using v3 console. I've ran the pi off of battery and see the same things so I can rule out the rpi's power supply.

Where does that comb looking interference come from?

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