Message-ID: <000201c08bb4$649a93c0$032bf7c2@oemcomputer>
From: "John Rabson" <word.factory@zetnet.co.uk>
To: rsgb_lf_group@blacksheep.org
References: <5.0.2.1.2.20010131074711.00a3d680@mail.pncl.co.uk><5.0.2.1.2.20010131074711.00a3d680@mail.pncl.co.uk> <3.0.6.32.20010131162350.0082a100@pop.saunalahti.fi>
Subject: Re: LF: CW etc
Date: Wed, 31 Jan 2001 18:25:55 -0000
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ICW orginally was CW interrupted at AF with an interrupter wheel.

See p. 129 of 'Radio Engineering' ed. Roy C Norris, pub. Odhams Press

----- Original Message -----
From: Väinö Lehtoranta <vaiski@dlc.fi>
To: <rsgb_lf_group@blacksheep.org>
Sent: Wednesday, January 31, 2001 2:23 PM
Subject: Re: LF: CW etc


> Hello all,
>
> Look for example "MIL-STD-188-140A" Appendix A
> ............
> 20.2.1 Interrupted continuous wave (ICW)
>
> ICW or on-off keying (usually associated with
> international Morse Code) can be used with
> VLF and LF systems, but is presently used only
> as a back-up. In the case of fixed shore base
> installations, ICW data rates are severely
> limited by the time constant of the antenna
> circuit......etc
>
> 20.2.2. Continuous wave frequency shift keying (CWFSK)
>
> -----------------
> 73 de Vaino
>
>
>
>
>
>
> At 11:48 31.1.2001 +0000, you wrote:
> >In message <5.0.2.1.2.20010131074711.00a3d680@mail.pncl.co.uk>, Walter
> >Blanchard <blanch@pncl.co.uk> writes
> >>For some reason this didn't seem to make it onto the reflector first
time
> >>round so here goes again:
> >>
> >snip
> >
> >>"CW" - "continuous wave" - means just that; a steady unbroken
unmodulated
> >>carrier wave; "N0N"  (or "A0" in old money).  Morse code is mainly sent
by
> >>interrupting the carrier so how can it possibly be "CW"?
> >
> >The old spark transmitters, produced damped wavetrains which carried
> >their own modulation (rough). When the arc system was produced which
> >gave a continuous waveform these were designated 'CW'. They required a
> >beat oscillator to hear them and even though they were interrupted by
> >the keying the nomenclature stuck.
> >
> >Mike
> >> Only amateurs
> >>consider "Morse" and "CW" to be synonymous which is a pity because it
> >>clouds our thinking.
> >
> >Commercial and armed forces transmitters have the Morse position
> >labelled 'CW' on the switch.
> >
> >Mike
> >--
> >M.J.Powell
> >
> >
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>  |  P.O.Box 50             ¤   Telephone: +358-9-4173965   |
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>