Respectfully-- my noise level is low enough now that I can use it as a
standard. I now have about an S2 background RFI noise on 40, and most
nights atmospherics are much worse, so I almost never hear RFI anymore,
at least on 40.
I felt that holding the vendor to a standard beyond that of my being
able to detect at the radio would not be fair, so I based my install
contract RFI threshold on what I could hear, not a limit that the vendor
may never be able to meet, and is of no difference to me, if I can't
hear it. So in other words, if my RFI background noise level is
acceptable, (and S2 is), then if I can't hear the heater RFI, it does
not exist for me, at that time.
Try and explain, (or put into writing), the need to meet sets of levels
arbitrarily picked for each band, across such and such a bandwidth, by a
customer for the subject heating unit, and no manufacturer will stick by
your tests, unless you happen to be a certified lab, and they happen to
agree with your limits.
If you do this, you will find yourself with no installer willing to go
the extra mile, and no vendor willing to back the installer up.
If on the other hand you put it in terms the installer understands,
using things he/she can hear, then you stand a lot better chance of
getting your RFI dealt with, and having a positive outcome from a new
heater install.
So just setting a limit to things, and saying this has to meet that
limit is not always the way to go... YMMV.
73s and thanks,
Dave
NK7Z
http://www.nk7z.net
On 07/09/2017 08:38 AM, John K9UWA wrote:
To say that one either Has Noise or doesn't have Noise with a Furnace or
any other device one needs to do a little qualifying along with that statement.
If you have enough "Other Noises" then you wouldn't know if the furnace
was making noise or not making noise. If your just setting there listening to
your radio on your antennas and you don't specifically hear something
different when a device starts up or stops or is running it may well be
creating noises you don't hear. The reason you don't hear it is because all
the other noises your radio is hearing are louder than this furnace or
whatever device your talking about.
You will have a lot more credibility if you stated that you had listened to your
furnace up close with some sort of sense antenna and a receiver capable of
hearing noise across a wide frequency range. The general noise level in one
location to another can vary by in some cases by several S Units.
I like my old Sony Transistor radio model ICF-2001 when looking for noise
sources. Others have mentioned other receivers and SDR's as well. Do a
walkabout your own property and house with one of these receivers and
then go kill your main breaker to the house and see the diffeence in your
noise level. Keep in mind sometimes killing the Main Breaker still doesn't
turn off some devices that have batteries or other methods of maintaining
power to the device for a period of time.
Please go read and study Jim K9YC's documentation on finding and killing
noises. Start here. http://audiosystemsgroup.com/KillingReceiveNoise.pdf
My Furnace and AC guy is an old family friend. When it was time for a new
one in this house I started with I don't want a furnace that maes RFI. His
next statement was. Then you don't want any furnace with a variable speed
air handler motor. Two Speed Motor is OK. Hi Speed for AC and low speed
for Heat cycle. The only thing I hear from it is a Click from the motor starter
in the AC unit. I can live with that much noise.
John k9uwa
John Goller, K9UWA & Jean Goller, N9PXF
Antique Radio Restorations
k9uwa@arrl.net
Visit our Web Site at:
http://www.JohnJeanAntiqueRadio.com
4836 Ranch Road
Leo, IN 46765
USA
1-260-637-6426
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