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KB2VXA > INFO 23.08.02 22:21l 38 Lines 1874 Bytes #999 (0) @ WW
BID : 55355_WT3V
Read: DB0FHN GUEST
Subj: Re: K0CQ > OMEGA
Path: DB0FHN<DB0ZWI<DB0HDF<DB0ERF<DB0MRW<OK0PPL<RZ6HXA<SP7MGD<WB0TAX<KB2TXP<
KB2FAF<WB2VPY<KB3BIU<WA3LWR<W2LV<KB2VLX<W2CXN<KC2COJ<WT3V
Sent: 020823/1732Z @:WT3V.#JS.NJ.USA.NOAM #:55355 [Lakehurst] $:55355_WT3V
From: KB2VXA@WT3V.#JS.NJ.USA.NOAM
To : INFO@WW
Hello Jerry and all,
The extremely low frequencies used to send one way messages to submarines
is the reason why the CW speed was so slow, it takes a certain minimum
number of cycles to properly form a character. Since it took forever and
a day to send a complete message making alerts impractical, it was
abandoned by the Navy. Positioning was another matter entirely.
The bit about the power companies sounds familiar, but not for the reson
it was "too wild". Such low frequencies are subject to disruption by
natural events, making signalling and control applications impractical. I
remember the NEAR alert system being beta tested by some power companies
back in the late 60s to early 70s. The idea was to provide weather and
other alerts to homes in the tornado prone Midwest so people could tune
in thier local broadcast station for information when they heard the
alarm go off. It used triacs to generate a strong third harmonic of the
power line frequency, but was subject to false triggering by lightning
strikes and other things which can generate a burst at that frequency.
That lead ballon was later successfully flown by the National Weather
Service which used a single tone burst to open the squelch of the
receivers so equipped. Today a multi tone system is used for regional and
local weather alerts and many more transmitters on more frequencies added
to the system. Just to make our lives a bit more interesting, broadband
Internet signals are being put on power lines in some countries while
authorization is being considered by others. Yet ANOTHER source of QRM we
will have to put up with!
**********************************
WAN: The sound of a baby computer.
**********************************
73 de Warren, KB2VXA
e-mail: kb2vxa@juno.com
Message timed: 17:34 on 23 Aug 02 UTC
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