Actually, looking for transformers will in most cases be disappointing. Most
people looking for noises immediately blame transformers when they are the
least likely to be the culprit on a power pole. I say this because it has
been proven time and again by the reps from Florida Power. Jim is right
about the Tecsun radios...they are pretty good and were also 'suggested' by
one of the RFI techs from Florida Power.
If you don't know the direction the noise is from you, then you have that to
find first. (If it is power company related, they are going to want to know
that for sure.) Then go hunting..try to find it on the HF freq (3.515) in AM
mode and then see if you can hear it higher up say on 20 mtrs or even 10
mtrs would be better. The higher in freq. the shorter distance the noise
travels. If you can hear it on 144 mhz you are likely very, very close to
the source. By the way, my buddy Mike, K4PRO in Bradenton, Fl had a similar
issue with the warbling/varying noise on HF, which turned out to be a Direct
TV Receiver in a neighbor's house. -Mike
-----Original Message-----
From: Hare, Ed W1RFI
Sent: Friday, September 05, 2014 6:49 PM
To: Rfi List
Subject: Re: [RFI] Noise on 3513.5
I wouldn't spend a lot of time trying to locate the source in my
neighborhood until I had hit the main breaker in my house. It is just much
easier to do that, even with a minor inconvenience, than it is to go souting
the neighborhood.
The most important question is not "what is it," but "where is it?" If
someone said it was a Sheetzu model 188 fly catcher, would that be of much
help trying to find it? And many noisy devices can sound the same, or sound
like a verbal description, so if someone's guess is wrong, you will spend a
lot of time looking for a device instead of finding where it is.
When you do get around to scouting the neighborhood, bring a handheld
receiver with an S meter. Start by going to every transformer on every pole
and putting the receiver about 2 feet from the ground wire that will be
present on every pole with a transformer. It is very likely that the noise
will be at least one S unit stronger on the pole connected to the source
premise.
Then
-----Original Message-----
From: RFI [mailto:rfi-bounces@contesting.com] On Behalf Of Jim Brown
Sent: Monday, September 01, 2014 2:28 PM
To: Hugh Valentine
Cc: Rfi List
Subject: Re: [RFI] Noise on 3513.5
Hi Val,
I've seen reports from others, and it was on my list to listen here. I just
did, both on my TX antennas and the Beverages, at about 11 am local time. I
see noise bumps from one or more switching power supplies on the
P3 spectrum display, but hear no birdies. Then I tuned my trusty TH-F6A to
3515 LSB and poked around the only Ethernet gear in my home and the CATV
cable. Nothing heard. Those were my first guesses, and came up negative.
My suggestion for chasing this is to do what I did, perhaps driving/walking
around with a mobile or handheld battery operated rig looking for it. The
TH-F6A has very poor sensitivity on HF, so you must be right by the source
to hear it. A better RX would be one of the excellent Tecsun receivers. I
own a PL380 (the smallest) and a PL660 (bigger, 3-6 dB more sensitivity, has
a BFO). QST just gave a glowing review to the PL880. In addition to their
virtues as SW RX, they are excellent on the FM broadcast band, and the
larger ones (660, 880) are quite good on the AM broadcast band.
73, Jim K9YC
On Mon,9/1/2014 10:49 AM, Hugh Valentine wrote:
Jim,
I have a varying, warbling, rough tone on 3513.5 CW with K3 running
on 12VDC battery, only rear connection is external antenna...using
K9YC 7T 5 Core Choke....All other stuff turned off/unplugged in
shack...Computer, Pwr Supplies, Modem, router, Fluorescents, etc.
I have a VHF "sniffer" that is quiet and does not show any source.
I have yet to Turn off the Mains...waiting for XYL to go out of Town
next week to try that.
Any thoughts as to the source?
Val
N4RJ
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