There was considerable interest in this so I'm posting a
follow-up. Apologies for not replying individually -- more
than 50 messages on this subject. ALL greatly appreciated,
both from fellow sufferers and those with suggestions!
---
Suggestions:
CATV box. Try turning it off and see if noise goes away. A
U-shaped aluminum cage around the TV, bottom center
grounded to TV ground helped in at least one case.
CATV leakage was mentioned in several replies. Try walking
around with a portable SW receiver tuned to the offending
noise frequency. (Q: CATV crud at 1.8 MHz? Oscillating
CATV line amplifiers, complex mixing products or ??)
FAX machine, esp. Sharp UX-510.
Navigational / distance measuring buoys (Long Beach Harbor)
Furnace control unit (switching control panel on the furnace
itself)
Touch lamps
When testing for noise in your own house, don't forget
battery-operated devices! (smoke detectors, etc.) Also
UNPLUG things, don't just turn them off. Many devices are
not completely OFF when turned off.
Laptop (whenever plugged in -- suspect something in its
charging circuit)
Computer power supplies (and power supplies in general).
CorCom 3VQ1 EMI Filters have cured it for some.
Battery chargers of any type
Broadcast spur
---
It seems a lot of things can "growl" on top band! Mine
isn't coming from my own house. I shut off power to the
entire house, removed batteries from all devices that use
them, and powered my receiver with a battery. No change.
I disconnected and terminated the CATV feed outside the
house. No change (obviously this does not rule out CATV
leakage however).
I will see if I can borrow a portable SW receiver and go
hunting. Meanwhile I hope to be putting up some receive
antennas soon -- maybe that will help (although this crud
is very strong).
Again THANKS to all. Good luck to all who have similar
problems!
73,
Paul
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