Smacking poles with a big hammer (with or without a transformer mounted on the
pole) will also help identify loose connections which may cause interference.
Even a portable AM broadcast band receiver can be used as the detector when
smacking poles. The power company may not be too anxious to believe you or
take action but are required by law to take care of the problem. A note to the
FCC will eventually git 'er done if they are not interested in getting someone
out to fix the problem.
73 Patrick AF4CK
From: Bob Kay
Sent: Sunday, December 02, 2012 8:35 AM
To: Patrick Greenlee
Cc: K0DAN ; flexradio@flex-radio.biz
Subject: Re: [Flexradio] Sweeping noise/signal across band
Here is how I locate it. I have an AOR 8000 portable receiver. I dial in the
offending freq and go hunting around the house. I've located a noisy
transformer on the pole. Smack the pole with a baseball bat. The vibration will
usually vibrate the laminations and you will hear it!
Sniffing the breakers will tell you what circuit it's associated with
On Sunday, December 2, 2012, Patrick Greenlee wrote:
I also see things running back and forth across the panadapter, relatively
localized humps a few dB above background. I don't hear them when they transit
my operating freq. I typically operate in Panafall Mode and every once in a
while I see a horizontal trace as some source sweeps through in freq. They
pique my interest but these anomalies do not interfere with my operation. I'll
check the UPS idea as there is one in the next room and another on a different
floor. When a band is quiet I do hear a steady repeated noise pulse on
approximate 1 sec rep rate but I suspect it is my electric fence charger.
Luckily it is just noticeable and not a problem, I wouldn't want to risk the
herd wandering where they shouldn't because I had to shut down the hot wire to
talk on the radio.
73 Patrick AF5CK
-----Original Message----- From: K0DAN
Sent: Saturday, December 01, 2012 7:56 PM
To: Bob Kay ; flexradio@flex-radio.biz
Subject: Re: [Flexradio] Sweeping noise/signal across band
Good point! I got this advice from someone earlier...but it wasnb t the UPS.
Nor was it anything else in my QTH domain. It comes and goees but does not
bother me too much. Part of the problem is the Flex panadaptor shows you stuff
thatb s there but you were aware of. Drives you crazy, but not a major
nuisance.
When trying to track down on-site QRM/QRN by using the trip-breaker
technique, it gets dicey powering stuff (Flex + Monitor + PC) unless you have a
totally portable station. I have a Flex 5000 I run with a PC/Monitor. AFAIK
they are all b cleanb , but running them 100% off the power grid is
problematic. When I substitute a battery or alternate PC, I have perhaps killed
one noise source but introduced a new one.
I will worry about it when these noise humps are S9+. Right now they are
below b 115dM, not on all bands, and are just annoyances.
73
Dan
K0DAN
From: Bob Kay
Sent: December 01, 2012 07:48 PM
To: K0DAN
Cc: flexradio@flex-radio.biz
Subject: Re: [Flexradio] Sweeping noise/signal across band
Check your UPS supply. You've described my situation exactly. I contacted UPC
and they had no interest in solving it. Unplugged the UPS and the problem is
gone.
On Saturday, December 1, 2012, K0DAN wrote:
There can be many sources of this. First and easiest thing to do is find out
if you're the cause of your own noise.
If possible, power your Flex from a battery or UPS, and use a laptop under
battery power as the PC. Then turn off all circuit breakers at your QTH and see
if anything changes. The breaks will kill any vampire power from your QTH
(power supplies, wall warts, HVAC fans, etc.). If the noise changes or goes
away, now start turning circuits back on and see what brings back the noise. At
that point you can better ID the source and look for mitigation.
If tripping your breakers doesn't do it, it's your neighbors and/or in your
environment, and might not be feasible to identify or resolve, esp in FL condo.
GL es 73
Dan
K0DAN
-----Original Message----- From: Steve Fowler
Sent: December 01, 2012 04:15 PM
To: flexradio@flex-radio.biz
Subject: Re: [Flexradio] Sweeping noise/signal across band
Welcome to urban noise pollution! At least that's my best guess. I have
switch mode power supplies in my house along with the PWM motor controller
on my furnace that make noise like that. The one I had that acted exactly
like yours was a SMPS powering my security cameras. The frequency changes
with minor variations in the load, which causes the drifting you see, and
the long wires feeding my cameras make great transmitting antennas. You
can track down and reduce or eliminate the noise coming from your own
house, but then you'll start picking it up from the neighborhood and beyond.
On Sat, Dec 1, 2012 at 3:50 PM, konrad schultz <konra...@hotmail.com> wrote:
Anyone having a similar problem. I see (on the panafall) and hear in the
headphones a sweeping signal or noise that regularly and slowly goes across
the band in time. Right to left and then back. Adds 20 db of noise to a
-119 db threshold on 20M CW. I am using my FLEX 3000 portable here at our
condo in SW FL. Ant is a portable dipole mounted on a camera tripod using
two MFG 20M whips and stands 3-6 feet off the ground. 50 Ohm coax. New
Lenovo laptop. All seemed to work fine at our QTH up north on 80M dipole -
which is up in two trees. Thoughts? Best, Konrad W1KON
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--
Best 73 de WA2SQQ
Elmwood Park, NJ
"The only dumb questions are those we don
--
Best 73 de WA2SQQ
Elmwood Park, NJ
"The only dumb questions are those we don't ask"
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