Thanks for all the great advise and information. Here is an update and a follow
up question:
I have identified these issues after a few weeks of research:
* (Small impact) My own ethernet switch/cable router created birdies around
14.03. Fixed with ferrites
* (large impact) My neighbor’s float charger for his truck and RV batteries
caused sinus wave forms with the tips about 15 db above noise floor which wiped
all weaker DX. The unit is a Schumacher Speed Charge, bought at Walmart. Fixed
by getting rid of and replacing with a different unit.
* (small impact) my neighbors ethernet switch creates similar birdies as
mine did. Will fix with ferrites.
* (medium impact) my two Trane XL 15i heatpumps. When they run the create
nasty spikes on 20 and 15, that are about 20kzh apart and about 5 – 10 db above
noise floor. I want to fix this.
Regarding the last item on my list, my heatpumps Trane XL 15i (with electric
auxiliary heat). I have verified that it does not seem to be the inside
blower, so moving my attention to the outside unit. I have taken a photo and
would like to try putting a few ferrites in there at the indicated locations.
https://photos.app.goo.gl/3ojRLrQvdQMAu1AR9
I could also put some preventive ferrites in the inside controller or maybe
even in the thermostat. But I thought this is likely the source and if I
prevent the noise to go out on the wires to the house, it may just fix it… Does
this make sense?
Any other suggestions, before I open these up and try it?
73
Andy
KU7T
Sent from Mail<https://go.microsoft.com/fwlink/?LinkId=550986> for Windows 10
From: Andy KU7T<mailto:ku7t@ku7t.org>
Sent: Saturday, November 10, 2018 13:57
To: rfi@contesting.com<mailto:rfi@contesting.com>
Subject: Investigating receive noise - got a few questions
Hi,
I am trying to sort out receive noise issues with my Flex.
I am not exactly sure how clean the spectrum could/should be. I have the
feeling that I may be more concerned about this just because I can see the
spectrum. I am in an residenial area with 5 acre lots, with miles to the next
town and businesses. I always throught/hoped I have no noise issues.
I took some time last night to turn off all breakers, one after another, until
only the shack was left. Then I reduced everything in the shack so the only
thing left was the 12V power supply, radio, computer and monitor. I also
adjusted the noise offset on the Alinco Powersupply with no changes, turned off
the computer, and unplugged it. At this point any wall warts, modems, routers,
etc were also off. Still no significant changes.
Take a look here at my spectrum, recorded while I turned off a breaker every 30
s. There is no difference between beginning and the end:
https://1drv.ms/v/s!AiAwh4TnZjYMhtoFCHwTeJdHO2MFGw
I really have not found any major decreases in hash or noise. Here are my
questions:
1. Do I go right about this at all? Should I only look at the ham bands
instead of looking at the half the HF spectrum?
2. There is quite some pulsing/jumping of noise going on below 10 Mhz (see
in video’s top spectrum). Are those normal static atmospheric crashes or
something else outside I should be investigating further and if so how?
3. There are patterns around 4 – 5 Mhz that are definitely some patterns
from some device. Is it worth worrying about these, considering there are not
near any ham bands of interest? Goes back to question 1 also: do I care whats
outside of ham bands?
4. I have some harmonics, some spikes between 12 and 15 Mhz. the distance
between the spikes is about 17.6khz. Any ideas what that could be? Is likely
not in my house though…
Any tips and ideas how to proceed?
73
Andy
KU7T
Sent from Mail<https://go.microsoft.com/fwlink/?LinkId=550986> for Windows 10
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