Can also be the power supply in a desktop as well. They are notorious for being broad-spectrum noise sources.
On Mon, Feb 1, 2021 at 2:16 PM Mark Brantana via BVARC <[email protected]> wrote: > I’ll check that out. Thank you. > > Sent from my iPhone > > On Feb 1, 2021, at 1:00 PM, Kirk KK2Z via BVARC <[email protected]> wrote: > > > Mark, > I had a bad laptop switching supply that caused the same broad spectrum > white noise you are describing. It was plugged into the same outlet as the > radio. My assumption was that it was a radio problem initially. Wiped out > radio receive to S9+20 white noise. > > I found it when I used a sw receiver and walked around looking for RFI > sources. Turned out to be 6" from radio. > 73, > Kirk KK2Z > > >> ---------------------------------------------------------------------- >> >> Message: 1 >> Date: Sun, 31 Jan 2021 19:33:20 -0600 >> From: Mark Brantana <[email protected]> >> To: BRAZOS VALLEY AMATEUR RADIO CLUB <[email protected]> >> Subject: [BVARC] QRM in new radio setup >> Message-ID: <[email protected]> >> Content-Type: text/plain; charset="utf-8" >> >> I am reaching out for ideas on a radio issue. I have installed an IC-745 >> Icom with an MFJ-2010 offset fed dipole. The power supply is a 20A MegaWatt >> switching power supply, which is located right next to the radio. The >> antenna is under some high power-lines with the long leg 90 degrees to the >> power-lines. I used my nanoVNA to study the band SWR response, and >> everything looks reasonable, though some small adjustments may need to be >> made. Nothing is grounded as yet. >> >> Here?s my problem. I am only attempting to receive at this time and I get >> consistent QRM white noise across all bands to the point where I can barely >> pick out some voices, etc. >> >> I am confident that the antenna is properly connected due to my antenna >> study. >> I don?t believe the power lines are an issue, since the problem would >> likely be more isolated show up as birdies at certain frequencies. >> The radio settings seem to all be correct according to the manual. >> Lack of grounding, but again the white noise is generally consistant >> across the spectrum. Still, this could be the problem. >> I have turned off my computer, so there no QRM from its power supply. >> It does not help to have the switching power supply right next to the >> radio, but other users give good reports on this model and no QRM issues >> are mentioned. >> I tried the radio at different times of the day on 20-m voice band, with >> the same noisy result. >> It could be the net result of a large number of small device >> transformers, but I doubt it. >> I turned off the wifi, and still no change. >> >> Hmm? I am a little stumped. Any thoughts or ideas? Personal experiences? >> >> Mark >> N5PRD >> >> ________________________________________________ > Brazos Valley Amateur Radio Club > > BVARC mailing list > [email protected] > http://mail.bvarc.org/mailman/listinfo/bvarc_bvarc.org > > ________________________________________________ > Brazos Valley Amateur Radio Club > > BVARC mailing list > [email protected] > http://mail.bvarc.org/mailman/listinfo/bvarc_bvarc.org >
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