Mark wrote:

Hi,
Then, shielding, choking, bypassing with caps come to mind. It's all by
trial and error. O'scope may come in handy.


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.

Mark

Yup,
EMI pollution!

"Dave" wrote in message
. ..


snip

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


I don't know about that! I had some work done which involved an upgraded
service entrance and new breaker panel. The electrician added a second
ground via a ground stake beneath the panel, despite the original (1967)
ground via the cold water inlet pipe being intact and sound.

(I will concede that he didn't quote chapter and verse in the NEC; he may
have been following a local code requirement. I know he wasn't padding the
bill, as he was doing the job at the behest of my son, from whose business
he was buying his supplies. (Still does.)

"Sal"

Motors with brushes are "incidental radiators" according to the FCC. I
believe PWM or variable frequency drive motors would be considered
"unintentional radiators" in that they intentionally generate a radio
frequency (9 kHz to 3,000,000MHz) but do not intend to radiate it. (see
definitions at http://www.hallikainen.com/FccRules/2007/15/3/).

Incidental radiators must use good engineering practice to minimize
interference (see http://www.hallikainen.com/FccRules/2007/15/13/).

Digital devices (I think motor control systems qualify as digital
devices) in appliances are exempt from the emission limits for
unintentional radiators (see
http://www.hallikainen.com/FccRules/2007/15/103/), though the user must
cease operation if the FCC finds it is causing interference.

"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.

/s/ DD



You bonded all the grounds, eh?

"Oscar_Lives" wrote in message
news:UKS5h.278091$1i1.256793@attbi_s72...

"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.

/s/ DD



You bonded all the grounds, eh?

no, the RF grounds are not bonded to the power grounds.

On 12 Nov 2006 20:38:46 -0800, wrote:

Motors with brushes are "incidental radiators" according to the FCC. I
believe PWM or variable frequency drive motors would be considered
"unintentional radiators" in that they intentionally generate a radio
frequency (9 kHz to 3,000,000MHz) but do not intend to radiate it. (see
definitions at http://www.hallikainen.com/FccRules/2007/15/3/).

And Part 15 limits the emissions from Unintentional Radiators, but the
limits are so high as to be of almost no protection to
radiocommunications within a hundred of metres or more of the emission
source.

Owen
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