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                     THE CGC COMMUNICATOR
                           CGC #985
                 Wednesday,  January 13, 2010
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               Robert F. Gonsett, W6VR, Editor
               <cgc (at) cgc333.connectnet.com>
   Copyright 2010, Communications General® Corporation (CGC)
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  ZEROING IN ON THE MYSTERY SIGNAL NEAR 1410 KHZ
  Very early Tuesday morning, Dennis Gibson wrote to the
CGC Communicator with the following clue as to the spurious
signal that we've been discussing.  Not only was he hearing an
audible heterodyne against the 1410 kHz stations, but he said,
"I'm hearing an almost identical (in pitch) het on 1390 at the
same time as 1410 including during the day in the two cars
Monday in Goleta, driving home at 4:30, and after midnight
at home in Santa Barbara...."
  Wow, two heterodynes of almost identical pitch (1,380 Hz
according to our earlier measurements) against stations on
both 1390 and 1410 kHz.  That could mean that a station on
1400 kHz was radiating spurs at 8.62 kHz on either side of
its carrier frequency and causing 1.38 kHz (1,380 Hz)
heterodynes against its first adjacent channel neighbors.
  Tom Koza was party to a private e-mail trail on Tuesday
morning where all of this was being discussed.  He listened
on both 1390 and 1410 kHz while driving into work along Route 14.
Tom confirmed hearing near identical pitched hets on 1390 and
1410 and also noted that the hets got stronger in areas where
the 1400 kHz station was stronger.  He was the first person to
identify the 1400 kHz station as KKZZ, Santa Paula (a full time
1 kW non-D facility).  Tom said, "It's a good bet" that KKZZ
is the source of the mystery signals.
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  CONFIRMING THAT KKZZ CAUSED THE SPURS
  Burt Weiner picks up the story from here.  Burt, Tom Koza
and Bob Gonsett had been corresponding about the situation
Tuesday morning, and Burt brought Chuck Hastings into the loop
since Chuck provides engineering services for KKZZ and a number
of other stations in that area (Chuck is a very experienced
engineer and is also a veteran CGC Communicator subscriber.)
  Here, then, are Burt's remarks from his letter time stamped
5:45 PM on Tuesday, January 12, 2010:
  "A few minutes ago Chuck Hastings and I were able to confirm
that KKZZ on 1400 is the source of the mystery signal.  Chuck
turned the KKZZ 1400 kHz transmitter off and back on several
times and at my location in Glendale I could hear the mystery
signal go off and on accordingly.
  "Now for a little history: The KKZZ NRSC proof done in 2007
showed two spikes/sidebands at approximately 8.7 kHz on each
side of the carrier, which obviously puts the two sidebands
approximately 1.3 kHz from the first adjacent neighbors at
1390 and 1410 kHz.  Several tests were made at that time and
it was determined that the problem was originating in telephone
company equipment that is used for the KKZZ STL.  The phone
company was able to do whatever it is they do and the problem
completely disappeared.  It now appears that the problem in the
phone line has reappeared.  Telephone company carrier systems
can produce a birdie in the 8 kHz region.
  "As you have seen in e-mails from earlier today, the issue
that was experienced back in 2007 has numbers that add up to
what we've been observing [lately].  Chuck also tells me that
KKZZ recently had problems with the phone line and that the phone
company replaced the line.  He's going to call the phone company
and get them to come out and resolve the problem."
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  CLOSING THOUGHTS FROM BURT
  "The first real clue was given by Dennis Gibson, WB6TNB, in
Santa Barbara.  Dennis noted that he not only heard the signal
when tuned to 1410 kHz, but also when tuned to 1390 kHz.  Based
on that observation, Bob Gonsett suggested that it might be a
spurious pair of sidebands coming out of a signal on 1400 and
proceeded to list several possible stations one of which was
KKZZ in Ventura.
  "The little wooden wheels in my head started to turn and when
the smoke cleared I recalled the telephone line problem at KKZZ
back in 2007.  Coincidentally, Hal Williams, N6TZ in Camarillo,
and Richard Rudman in Santa Paula, had been following the drama.
Both took a listen from their respective homes and heard the
two sidebands centered around KKZZ.  I advised Chuck Hastings
about this possibility in an e-mail and Chuck promptly called
me and we proceeded to confirmed that it was indeed KKZZ.
  "This is why it's wise to do NRSC Proofs!"
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  CLOSING THOUGHTS FROM CGC
  Another mystery solved thanks to alert and cooperative
broadcast engineers.  There was no need to mount a time-consuming
direction finding expedition and the FCC was not asked to get
involved.
  The real hero in this case is Dennis Gibson.  It was his
clue that turned the tide and concluded the hunt on short order.
If you enjoyed reading about this case, you might drop him a
note at <wb6tnb (at) cox.net>.  Job well done!
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