wrote in message
ups.com...
Mark wrote:
Dave wrote:
Mark wrote:
modelman wrote:

Several months ago I had a high efficiency Trane XV90 natural gas
furnace and heat pump installed. Since the weather has recently been
cold enough for the gas furnace to provide heat, I have been
experiencing severe radio interference. The interference wipes out
AM
broadcast reception throughout my house. I also see snow on a TV
connected to an external antenna.

The radio noise occurs as soon as the draft inducer motor starts up;
the pitch of the interference is related to the motor speed. The
draft
inducer motor is a dc motor driven by a PWM controller on the main
circuit board. ... SNIPPED ...

DC motors are notorious noise generators. Those of us who used to be
mobile when
6 VDC was the value of a car battery, and alternators did not exist,
will attest
to the facts of generator [DC motor] noise.

A DC motor uses brushes to contact windings within the motor. As the
motor turns
the brushes continually make and break current in the rotating armature
[inductance]. This making and breaking creates a very wide HF and lower
VHF
noise spectrum. [Lots of sparks].

The solution, in the olden days, was a coaxial capacitor mounted
directly to the
frame of the motor with the DC power running through the capacitor. I
recall the
capacitor was about 1 inch in diameter and 2 inches long. Sprague made
such a
critter.

Hope this history helps.

/s/ DD, W1MCE

I'm pretty sure these motors don't have brushes and are electronically
commutated and the electronics are causing the EMI...
Mark

Hi Mark, Modern HVAC, dishwashers, washing machines,ect. use variable
speed drives, which increases the efficiency of the devices. The
increased efficiency produces increased RFI due to the switching action
of the solid state devices (SCR's, BJT's, IGBJT's.ect). My washing
machine drives me crazy on Sat. morning on HF as my maid does the
weekly wash. As for what you can do? I don't know, it would require
vast amounts of filtering at the drives, I am sure that Trane and
other mfgrs are not willing invest in.

This is completely different from the usual thermostat interference,
and will be much more difficult to get rid of.
Gary N4AST

Gentlemen Hi
and there is nothing that could be done to force OEMs
for clean up this interference (RFI?) That is nice but
you and I if interfere with some one TV in Neighborhood
FCC would be all over our ass thanks for equal justice
KA2AYS

"Dave" wrote in message
. ..
Noon-Air wrote:

SNIPPED

As Jake said.... with the addition of....
Make sure that you have proper earth grounds for your power, and the HAM
rigs/shack. That will go a long way towards eliminating RFI. Make sure
that all the bonding screws in the furnace are clean and tight, make sure
that the furnace has a proper ground also.
When I put the shack together, I drove a seperate 8ft copper ground rod,
and silver brazed #6 solid copper to it, then silver brazed the wire to
the copper ground buss on the back of the bench. All equipment
grounded.....no problem.

de n6ojn



As you describe your setup it does meet USA National Electrical Code. Your
home should have ONLY one earth connection, not two!

Actually as I live in a lightening prone area, my home has several earth
grounds as do most of the other buildings in the area.

As you describe it, your house presumably has the electrical service panel
grounded to an 8 feet long ground rod where the service enters the house.

The main service panel has 2 ground rods tied to the same buss, The TV cable
entrance has a seperate earth ground, as does the telephone entrance, and
the sub panel in the garage.

You seem to have added a second 8 feet ground rod to your home specifically
for the Ham station.

Yes and that one too.

Check with a local electrician for specific compliance issues.

done did... the sparky is the one that put the extra rods in for the service
entrance and the garage sub panel, and the city inspector signed off on it.

/s/ DD

"John Smith" wrote in message
...
Mark wrote:
Dave wrote:
Mark wrote:
modelman wrote:

/s/ DD, W1MCE

Mark


Mark:

A quick check of the web turned up a site with posts dealing with the
same problem you are experiencing, it seems someone was able to make
some noticeable improvements in the rf interference generated--but not
totally eliminate... Just might be worth you time time to look, the
link I will paste is a long one, if it wraps you may have to copy and
paste both lines into the address bar of your browser and make sure
there have been no breaks, spaces, caused the whole link. Hope this
helps...


http://groups.google.com/group/alt.h...eb8ab594ac0781

Regards,
JS


--Followed your link and was surprised to see that my comments, posted over
a year ago, are still floating around cyber space. Obviously apparent, that
the Trane RF noise problem hasn't been addressed by them. What is
disconcerting is that they have done nothing to minimize or alleviate the
problem and after more than a year are still producing furnaces with a known
RF noise generating inducer motor. Clearly a case of COST vs Customer
satisfaction---Charge more for the furnace, if that what it takes, and go
back to the motor that didn't have this problem. In my case, I had a
perfect back-to-back comparison--in the morning the first furnace worked
without incident--by noon, the new furnace was screwing up my (rabbit ears)
kitchen TV. I took a look at the new furnace and immediately saw that the
inducer motor was different--size and configuration. With a little bit of
experimentation, I finally narrowed the cause down to the inducer motor.
The installer had no clue, was very helpful and cooperative in interfacing
with Trane. Since I must have been early in the "new motor" time frame,
Trane shot-gunned the problem trying to eliminate it, ----new control board,
verifying electrical grounds, replacing the shielded motor harness (the
only thing that showed some signs of improvement). I guess at that point
they must have figured out that it was a bigger problem then they expected
and that's when the Trane Rep stopped returning my calls. It was easier to
run a cable line to the TV then to continue dealing with the installer, who
was shrugging his shoulders by this time, and the vanishing Trane Rep
MLD

"Noon-Air" wrote in message
. ..

"Dave" wrote in message
. ..
Noon-Air wrote:

SNIPPED

As Jake said.... with the addition of....
Make sure that you have proper earth grounds for your power, and the HAM
rigs/shack. That will go a long way towards eliminating RFI. Make sure
that all the bonding screws in the furnace are clean and tight, make
sure that the furnace has a proper ground also.
When I put the shack together, I drove a seperate 8ft copper ground rod,
and silver brazed #6 solid copper to it, then silver brazed the wire to
the copper ground buss on the back of the bench. All equipment
grounded.....no problem.

de n6ojn



As you describe your setup it does meet USA National Electrical Code.
Your home should have ONLY one earth connection, not two!

Actually as I live in a lightening prone area, my home has several earth
grounds as do most of the other buildings in the area.

As you describe it, your house presumably has the electrical service
panel grounded to an 8 feet long ground rod where the service enters the
house.

The main service panel has 2 ground rods tied to the same buss, The TV
cable entrance has a seperate earth ground, as does the telephone
entrance, and the sub panel in the garage.

You seem to have added a second 8 feet ground rod to your home
specifically for the Ham station.

Yes and that one too.

Check with a local electrician for specific compliance issues.

done did... the sparky is the one that put the extra rods in for the
service entrance and the garage sub panel, and the city inspector signed
off on it.

Good. Enjoy your ground loops, and have fun replacing appliances the next
time lightning hits close. Don't even think of surviving a direct strike.

"Mark" wrote in message
oups.com...


Well that's my concern.
There are more and more of these kinds of units being installed
everyday.
We can't "home brew" a fix for all of them.
Someone needs to get to the FCC or to the manufacterer to fix this at
the source before it gets worse.

Maybe "turn them in" to the FCC for a _finders fee_? :O)

-zero

AKS wrote:

SNIPPED


Gentlemen Hi
and there is nothing that could be done to force OEMs
for clean up this interference (RFI?) That is nice but
you and I if interfere with some one TV in Neighborhood
FCC would be all over our ass thanks for equal justice
KA2AYS



Not quite true!

I run 1KW on low bands [75 and 20 meters]. I have a tuner and low pass filters
in line. My station is properly grounded to the service panel ground/earth rod.
This connection is also the equipotential surface for the operating position.

My station meets ALL FCC requirements.

If a neighbor's tv, phone, stereo, or whatever, picks up my transmissions the
problem is with their equipment and I am NOT responsible for correcting the
situation. I will advise them regarding what needs to be done at their end and
at their expense. The best demonstration is to invite them into my station and
have them witness my tv, phone, stereo etc., being interference free.

The best demonstration is an RFI free home station.

We, hams, are not responsible for deficiencies in consumer electronics. That
rests with the manufacturer. The next time you buy a stereo read the Part 15
compliance statement!

Most likely it states, I paraphrase, this equipment MAY receive interfering
signals from near by transmitters. Buyer Beware!

/s/ DD

Dave wrote:

AKS wrote:

SNIPPED



Gentlemen Hi
and there is nothing that could be done to force OEMs
for clean up this interference (RFI?) That is nice but
you and I if interfere with some one TV in Neighborhood
FCC would be all over our ass thanks for equal justice
KA2AYS


Not quite true!

I run 1KW on low bands [75 and 20 meters]. I have a tuner and low pass
filters in line. My station is properly grounded to the service panel
ground/earth rod. This connection is also the equipotential surface for
the operating position.

My station meets ALL FCC requirements.

If a neighbor's tv, phone, stereo, or whatever, picks up my
transmissions the problem is with their equipment and I am NOT
responsible for correcting the situation. I will advise them regarding
what needs to be done at their end and at their expense. The best
demonstration is to invite them into my station and have them witness my
tv, phone, stereo etc., being interference free.

The best demonstration is an RFI free home station.

We, hams, are not responsible for deficiencies in consumer electronics.
That rests with the manufacturer. The next time you buy a stereo read
the Part 15 compliance statement!

Most likely it states, I paraphrase, this equipment MAY receive
interfering signals from near by transmitters. Buyer Beware!

/s/ DD

It should also state that the device may not emit any interfering signals.

Dave WD9BDZ

Mo Hoaner wrote:
"clifto" wrote...
Anything that generates RF inside the USA is regulated by the FCC. If your
cat's butt emits RF in the USA it's regulated by the FCC.

Wrong. If the cat's butt emits RF, it's regulated by the FCC. But, digital
equipment used only in transportation vehicles - busses, cars, aircraft -
and equipment used in appliances - HVAC equipment mentioned specifically -
are exempt from Radio Frequency Device regulations. The rule says "....are
exempt from the specific technical standards and other requirements
contained in this part. The operator of the exempted device shall be
required to stop operating the device upon a finding by the Commission or
its representative that the device is causing harmful interference".

Interesting. I've never heard that before. Thanks for the correction.

Not that that doesn't suck...

--
"A man's country is not a certain area of land, of mountains, rivers, and
woods, but it is a principle; and patriotism is loyalty to that principle."
-- George William Curtis

"David G. Nagel" wrote in message
...
Dave wrote:
Snipped...

It should also state that the device may not emit any interfering signals.

Actually, most of the stuff being talked about here is exempted by the FCC
from testing. Basically, any digital stuff in appliances, and vehicles is
exempt from showing compliance. That doesn't mean it's allowed to cause
harmful interference, but the exact definition of "harmful" is a grey area.




Dave WD9BDZ

Mo Hoaner wrote:
"David G. Nagel" wrote in message
...

Dave wrote:

Snipped...


It should also state that the device may not emit any interfering signals.


Actually, most of the stuff being talked about here is exempted by the FCC
from testing. Basically, any digital stuff in appliances, and vehicles is
exempt from showing compliance. That doesn't mean it's allowed to cause
harmful interference, but the exact definition of "harmful" is a grey area.




Dave WD9BDZ



Exempt from FCC compliance testing but not from Part 15 compliance.
Intentional and Unintentional radiators must comply with Part 15. There
is still a permissible level of signal emitted under this Part i.e.
Unlicensed two way radios.

Dave WD9BDZ