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
<[email protected]> wrote:
I will check all these things.
Sent from my iPhone
On Jan 31, 2021, at 10:16 PM, Doug SEYLER via BVARC <[email protected]> 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 <[email protected]> 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
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On Sun, Jan 31, 2021 at 8:45 PM Rick Hiller <[email protected]> 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
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On Sun, Jan 31, 2021 at 7:33 PM Mark Brantana via BVARC <[email protected]> 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
[email protected]
http://mail.bvarc.org/mailman/listinfo/bvarc_bvarc.org
--
Rick Hiller e-mail: [email protected]:
832-474-3713Physical: 9031 Troulon Drive Houston, TX 77036
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--
Rick Hiller e-mail: [email protected]:
832-474-3713Physical: 9031 Troulon Drive Houston, TX
77036________________________________________________
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
________________________________________________
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
