[RFI] Odd RFI case I'm working on...

[Dave (NK7Z)]

Hello RFI group,

I have an RFI case I am working on right now, that has stumped me 
completely...

A fellow Amateur has an Laing under sink recirculation pump model 
ACT-303-BTW.  Every time he transmits, the pump kicks in.  The following 
steps have been tried.

1.  A Pile of clamp on ferrites have been added to the short power cord, 
maybe 5 of them.  No room yet to wind on an FT250-31, but that may be next.

2.  The water piles have been connected to ground, using a car jumper 
cable.  The person who put this on tells me he used the ground on a 
outlet...  Yes, we will test differently with a real ground at some 
point soon.

3.  He has reduced power to 50 watts and the pump still kicks in.

4.  He has wrapped the pump in foil, and grounded the foil.  Again, I am 
sure via the outlet ground.

5.  His dipole, which is close to the home, has a quality Balun Design 
choke on it at the feedpoint.

6.  The coax has been rerouted to as far as possible from the device as 
possible, running on the ground as a test.

The device is an older one, and sits under the sink.  The ham is not 
sure if his cold water pipes are at actual ground.

I intend to do the following:

1.  Use a real ground, if needed to ground the cold water pipes to the 
service ground then bond to the pipes at the pump.

2.  Replace the power cord with a longer version, and wrap 12 turns of 
AC line cord in an FT240-31, and/or add an external RF filter to the AC 
line.

3.  Reduce power further to try and pin down where the RF is getting in, 
pipes, or power line by isolation.

Purchase a good RF filter for the AC line.  Can someone suggest an OTS 
one I can recommend?  He operates 80-10 Meters...

Any other ideas?????

73, and thanks,
Dave (NK7Z)
https://www.nk7z.net
ARRL Volunteer Examiner
ARRL Technical Specialist, RFI
ARRL Asst. Director, NW Division, Technical Resources

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