[MilCom] Anatomy of a Search

Duane Mantick wb9omc at yahoo.com
Thu Jan 31 21:05:02 EST 2008


Hmph.......not sure what to make of that.  AM probably
would have been a more likely choice for voice at
121.5; last I knew most if not all civilian airband
stuff was not in SSB but rather in AM.

As for the ELT, Wikipedia refers to its transmission
as an "anonymous siren tone" but doesn't specifiy the
mode of transmission. Considering the age of ELT
technology, I'd guess AM but I could be wrong.

Interesting aside - the same article also says that:

"As per 14 CFR 91.207.a.1, ELTs built according to
TSO-C91 (of the type described below as "Traditional
ELT, unregistered") have not been permitted for new
installations since June 21, 1995; the replacing
standard was TSO-C91a. Furthermore, TSO-C91/91a ELTs
are scheduled to phased out February 1, 2009 to be
replaced by the 406 MHz [28] ELT, a far superior
unit.[29]

Though monitoring of 121.5 and 243 MHz (Class B)
distress signals by satellite is scheduled to cease in
2009, there is currently no upgrade of older ELT units
mandated by the FAA for aircraft in the United
States."

Anybody with an interest in emergency location might
want to check out the Wiki article:

http://en.wikipedia.org/wiki/Emergency_Locator_Transmitter

======================================================


It's also possible that these signals were bogus from
a "jammer", and CAP et al had better things to do that
try and chase him down.  That's the sort of thing that
happens now and then - unfortunate but it does happen.
 The FCC periodically nabs somebody illegally on the
airband (or elsewhere) interfering with critical
transmissions and generally hangs them out to dry.  If
that's what you've got out there, keep your ears open
and see if it crops up again.  If you can keep a tape
recorder nearby and get some sample of the audio for
them it can be very helpful in nabbing such a
"jammer".

Duane
WB9OMC

--- KD7JYK DM09 <kd7jyk at earthlink.net> wrote:

> There was a brief and undetailed mention by CAP or
> SAR in a local newspaper
> with no follow-up that I could ever find.  I didn't
> hear voice on 121.5
> during the search, I was listening in USB and CW for
> an ELT while driving
> through-out the region, but did hear what sounded
> like an attempt at CW a
> couple of days after the mention of attemped voice
> contact.  The key-ups
> were slow and erratic, I was unable to make any
> sense of it.
> 
> Kurt
> 
> ----- Original Message -----
> From: "Duane Mantick" <wb9omc at yahoo.com>
> 
> : Curious, is that something that you heard
> personally
> : or that someone passed on to you?
> 
>
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