Are you using a Plasma TV set? I have heard some say they dont have the issue, but 90% of plasma, including mine, will totally overtake all bands from 160 to 440 and make your radio unusable. On Monday, February 1, 2021, 08:47:42 AM CST, Mark Brantana via BVARC <bvarc@bvarc.org> wrote: I will check all these things. Sent from my iPhone
On Jan 31, 2021, at 10:16 PM, Doug SEYLER via BVARC <bvarc@bvarc.org> wrote: If you have. A battery powered sw receiver, check to see if it is present there. If so, trip the main power to the house to see if it goes away. RFI can be very broad banded. I’ve had power line noise that extends cripples a lot of the spectrum. Doug W9LCQ Sent from my iPad On Jan 31, 2021, at 9:00 PM, Rick Hiller via BVARC <bvarc@bvarc.org> wrote: Although it is a Ham Band antenna for 40,20,10....you might try listening to General Coverage and tune to 10, 15 or 20 MHz for WWV......see if you can hear it.....from what you say, I doubt it, and if so, you have a radio set up issue, IMHO.....Rick | | Virus-free. www.avast.com | On Sun, Jan 31, 2021 at 8:45 PM Rick Hiller <rickhille...@gmail.com> wrote: Mark, A few questions, comments and tests:Sounds like a radio problem to me...so....not in any particular order, just what I thought of first to last.....-- What S level is the noise? Does it change level with the RF Gain control? -- What if you disconnect your antenna coax? Does it go away?-- What if you connect a dummy load? Same noise?-- What does the Nano VNA show? Impedance wise (R and j) and SWR? What is the SWR bandwidth of the antenna across 40 and 20?-- Where is your RF Gain pot? Maxed? Try reducing the setting a bit.-- Do you have your "pre-amp" on? If so, turn it off. NB off too.-- What about CW mode....does the Narrow filter on make a difference?-- Where are the IF/PBT shift sliders set? They should be in the center for a base reference. -- Are the rear panel Receive Antenna In and Out jacks jumpered and is the jumper OK continuity wise? -- Is the Ham/General select switch in Ham position? I am not sure if the band pass filters are bypassed in General....just a guess. -- Take your coax off. Then using ONLY the center pin of the PL-259 insert it into the radio SO-239 center ONLY. Is the noise similar? Then screw on the PL-259 outside....does the noise change? Usually, using only the center pin causes lots of receive noise and then when you screw on the 259 outside the noise reduces as the antenna system is then a closed system.You can also do this with a 10 foot long piece of wire and just connect the wire to the inside center terminal of the SO-239 on the radio. The receive noise should increase when you touch the wire to the center pin......is this noise the same as you are complaining about? Have you run power to the antenna? What is the SWR? Similar to the Nano reading? Use the internal SWR meter and meter switch to select RF PWR and SWR set etc. That's about it for a 745 brain dump for tonight. Something is amiss in your set up, IMHO, no external wideband white noise source is jacking with ya. Sounds like receiver noise is at max gain and no received signals are being processed. GL and 73...rick -- W5RH | | Virus-free. www.avast.com | On Sun, Jan 31, 2021 at 7:33 PM Mark Brantana via BVARC <bvarc@bvarc.org> wrote: 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? MarkN5PRD________________________________________________ Brazos Valley Amateur Radio Club BVARC mailing list BVARC@bvarc.org http://mail.bvarc.org/mailman/listinfo/bvarc_bvarc.org -- Rick Hiller e-mail: rickhiller73@gmail.comCell: 832-474-3713Physical: 9031 Troulon Drive Houston, TX 77036 | | Virus-free. www.avast.com | -- Rick Hiller e-mail: rickhiller73@gmail.comCell: 832-474-3713Physical: 9031 Troulon Drive Houston, TX 77036________________________________________________ Brazos Valley Amateur Radio Club BVARC mailing list BVARC@bvarc.org http://mail.bvarc.org/mailman/listinfo/bvarc_bvarc.org ________________________________________________ Brazos Valley Amateur Radio Club BVARC mailing list BVARC@bvarc.org http://mail.bvarc.org/mailman/listinfo/bvarc_bvarc.org ________________________________________________ Brazos Valley Amateur Radio Club BVARC mailing list BVARC@bvarc.org http://mail.bvarc.org/mailman/listinfo/bvarc_bvarc.org
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