Thanks to all who responded to my query re. how to prevent rf from
turning these lamps on and off.
At midnight of the first night of the ARRL 160 contest I had an irate
'neighbor' phoning to tell me to stop using my radio as it was
keeping her awake by turning her nighttable lamps on. Their house is
a good quarter mile away!
I supplied an extension cord wound about 12 turns on an FT240-77
toroid core. It has apparently stopped the rf activation. (I could
not hear the rf produced by their lamps at my qth, fortunately.)
Below are some of the suggestions I received. I have not included
some of the most colorful suggestions having to do with innovative
ways of destroying the lamps - no doubt the best solution of all.
By the way, I just solved another rfi problem with a telephone answering
machine. Toroids on the cord from the 9volt adapter and on the phone
line did not work on this one as they had on my other machine, nor
did a series pi type phone line filter.
I then connected .05 disk caps from the 9 volt line to the phone line
to put the power input and the phone at the same rf potential - no
more turning on my wife's business line machine whenever I key up!
73, Rod VE7FPT
SUGGESTIONS RECEIVED BELOW
-------------------
Seriously, people have tried various ferrite cores, etc. Best thing
I've heard is to disassemble the unit and bypass the AC line with
.01uF/1kVDC caps right at the control board.
73, Ward N0AX
--------------------
Rod, I just used some simple toroidal chokes (snap-on) with the a.c.
cord wrapped as many times as possible between lamp and plug. RF
hasn't turned them on since. Others have built some filter circuits
with success. GL....Jim K2JL
---------------------
I can give you a brief idea of what I did to a few of my touch lamps
here a few years back. Parts values are vague. What I did was on all
of my lamps I inserted a small choke in parralel with about a 1k
resistor in each of the ground sensing wires attached to the metal of
the lamp. I made the chokes by taking a vey small peice of plastic,
like a bic pen, but smaller, and putting about 25 turns of the finest
wire I could find. (#30awg??) on a 1.5" chunk of this plastic. Finer
wire would be better, as I think slightly longer would be too, but I
only had the one peice, hi! Anyway, the odd time you have to tap the
lamp 2 or 3 times to get it to come on as I geuss it's ability to
sense current to ground is diminished somewhat. The stray RF that the
lamps generate across the spectrum is also reduced (but not
eliminated) and they are also not as prone to RF from my HF signals as
before., Again not immune, but much better. I eventually convinced
the wife to let me rip out the guts of all 3 lamps as the crap they
were emmitting was just too much for my weak signal work. Good thing
we bought them on sale. I think for "normal" hf you might not notice
the crud, especially if your antennas are away from the house further
than all of mine. Mine are all very close. The tip came from a QST in
"HINTS n' KINKS" column a few years back (I think) so maybe someone
can give you exact values. Each lamps' preformance varied. Hope this
helped somewhat! MIKE Michael & Coreen Smith (AA Antennas & Wynder
Photography) 271 Smith Rd, Waterville, Sunbury Co.,NB, Canada E2V 3V6
----------------
I have a Sears lamp in the bedroom that used to go nuts on 80M.
Wrapped the line cord around a FT240-77 toroid and no more problem.
Others have had to open the lamp and install a RFC and cap at the
input of the FET trigger amp.
GL.....Carl, km1h
---------------------
Roger Graves
Victoria, BC
CANADA
--
FAQ on WWW: http://www.contesting.com/topband.html
Submissions: topband@contesting.com
Administrative requests: topband-REQUEST@contesting.com
Sponsored by Akorn Access, Inc & KM9P
|