From: Brad Bradfield QLF
Subj: RFI, APRES' SKIING, ETC - - - - - - - -
Good morning QRP'ers and QRP'ettes - -
I just recently tracked down (and hopefully cured) a bit of RFI that was
affecting my Wilderness Sierra. I would occasionally hear various noise bursts
of moderate strength in the headphones when using the Sierra. Thinking this to
be just the norm on 40-meters, I didn't pay much attention to it for a long
time. Then one night, out of the corner of my eye, I noticed the red or green
panel indicator lamp (transmit or received signal indicators) on my Kenwood
TR-751A packet rig (know where I'm going here?) seemed to be in sync with the
bursts heard in the headphones. Well, my operating desk is basically a couple
of stacks in the center-rear of my desk consisting of a Hallicrafters S-38, a
couple of Knight-Kit receivers, a Johnson Matchbox (hey I like Boatanchors too,
ok?), the Sierra, my MFJ-971 tuner, the Kenwood TR-751A, packet modem, 286 PC,
keyer, paddles, SWR analyzer, field strength meter, etc. Well, the noise burst
was occurring everytime there was a data transfer in either direction between
the packet modem and computer on the RS-232 bus. Placing a snap-on ferrite
core on the RS-232 cable removed or at least greatly reduced this noise burst.
Eventually I will be rearranging the desk, and should be able to get the packet
and QRP stations seperated enough to reduce problems too. Look around you if
you're having RFI problems. The source may be closer than you think.
FYI, I will be in Winter Park, Colorado on a ski trip March 18-21, and will be
taking my Sierra along for a bit of apres' ski hamming. (Hey, I'm 49 years
old and married. Any other apres' ski activities went out the window years
ago!) The evenings available for hamming will be the 18th through the 20th,
with the 19th and 20th being the most likely. Operation will be on 40 and 80
(gotta get the 80-meter band module built) with 30 being a daytime possibility
on a very sporadic basis. As the dates get closer, I'll post some possible
times and frequencies. I'd love to work some of you QRP-L folk. Anybody else
going to be in Winter Park that week?
72's es 73's,
Brad, WB0CGH
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Brad Bradfield, PE Electrical Design Engineer
(H) 817-321-2960 Texas Instruments, Inc.
(W) 972-462-6230 (Soon to be: Raytheon/TI Systems)
Real men talk with their fingers!
QLF@MSG.TI.COM
WB0CGH@WO5H.#DFW.TX.USA.NA
ARRL Life Member QRP-L #377 SMIRK #4906 IEEE(M) ARS #72
Collector of wireless and landline Morse keys and accessories.
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