A PRF of 363 ?
73 Jeff kb2m AOS-270
----- Original Message -----
From: "James Duffer" <dufferjames@hotmail.com>
To: <tentec@contesting.com>
Sent: Wednesday, April 27, 2005 11:59 AM
Subject: Re: [TenTec] cw creation
> Thanks for the research Martin.
>
> I am a retired FAA type that worked at a long range radar (ARSR-1D) that
> fed
> the Memphis Center (ARTCC). The method that the radar generated a signal
> was kinda like CW. A magnetron was keyed with a pulse (dit) at about 363
> pulses per second (high speed dits hi). Of course this keying was a very
> high pulse of shaped negative voltage about 2 microseconds wide applied to
> a
> magnetrons cathode. A pulse forming network shapped this pulse. During
> this pulse, the magnetron a "cross field device" went into oscillation at
> a
> frequency in the "L" band that was determined by its cavity. Now we have
> a
> pulse consisting of RF energy. Again kinda like CW with rapd short
> dits.
> Of course this was a "P" type of modulation not A type but still very
> similar. And of course CW does have sidebands, determined by the rate and
> shape of the dit/dah (duh).
>
> I of course with my CW sending do not have to worry about generating a
> wide
> bandwidth as my speed is slow enough to be safe!
>
> 73 to all, de wd4air
>
>>From: "Martin, AA6E" <martin.ewing@gmail.com>
>>Reply-To: "Martin, AA6E" <martin.ewing@gmail.com>,Discussion of Ten-Tec
>>Equipment <tentec@contesting.com>
>>To: Steve Baron - KB3MM <SteveBaron@starlinx.com>,Discussion of Ten-Tec
>>Equipment <tentec@contesting.com>
>>Subject: Re: [TenTec] cw creation
>>Date: Wed, 27 Apr 2005 11:39:43 -0400
>>
>>On 6/26/06, Steve Baron - KB3MM <SteveBaron@starlinx.com> wrote:
>> > How does the FCC define CW?
>> >
>>Having nothing better to do, I went to the FCC website to read up on
>>Part 97 and what they say about CW. The relevant sections are 97.3
>>which refer back to 2.201 and 2.202. Some excerpts are at the end.
>>Classical amateur CW might be 100HA1A, specifying 100 Hz bandwidth,
>>or simply A1A. The ARRL FCC Rule Book has some useful material, too.
>>
>>It seems that the FCC is interested in the signal that shows up on the
>>air and not how it is generated. Fair enough. Everything we have
>>been talking about in this forum is A1A, I believe. Some generation
>>methods (like tones into a poor SSB rig) are worse than others. FCC
>>requires signal purity to observe good engineering practices, or words
>>to that effect, and that may rule out the KWM-1 technique nowadays.
>>The DSP method (e.g., Orion = TenTec content!) can be as perfect as
>>you're willing to pay for.
>>
>>As the Rule Book (8th ed.) explains, it would be possible to narrow
>>the "100 Hz" DSB spectrum of an A1A signal by eliminating one sideband
>>(50 Hz) and suppressing the carrier. (However you make it, CW does
>>have a carrier and sidebands just like a voice signal.*) I wonder if
>>anyone has ever done it, and whether a half-width carrier-less CW (or
>>psk31?) signal would be decodeable after HF propagation. You'd need
>>really tight frequency and passband control.
>>
>>73, Martin AA6E
>>
>>*A carrier? What about between characters? Yes, mathematically the
>>carrier is still there -- even after you turn your rig off. Of
>>course, there are also very low freq sidebands that conveniently
>>cancel out the voltage... So your rig had better be very very linear
>>or it won't be safe to shut off the power! Don't lose sleep over it.
>>;-)
>>================================
>>97.3(c)
>> (1) CW. International Morse code telegraphy emissions having
>>designators with A, C, H, J or R as the first symbol; 1 as the second
>>symbol; A or B as the third symbol; and emissions J2A and J2B.
>>
>>2.201
>>(c) 1st symbol
>>
>>(2) Emission in which the main carrier is amplitude-modulated
>> (including cases where sub-carriers are angle-modulated):..........
>> --Double-sideband................................................. A
>> --Single-sideband, full carrier................................... H
>> --Single-sideband, reduced or variable level carrier.............. R
>> --Single-sideband, suppressed carrier............................. J
>>...
>> --Vestigial sideband.............................................. C
>>...
>>
>>(d) Second Symbol--nature of signal(s) modulating the main carrier:
>>
>>...
>> (2) A single channel containing quantized or digital information 1
>> without the use of a modulating sub-carrier, excluding time-
>> division muliplex..................................................
>> (3) A single channel containing quantized or digital information 2
>> with the use of a modulating sub-carrier, excluding time-division
>> multiplex..........................................................
>>...
>>
>> (e) Third Symbol--type of information to be transmitted:\2\
>>---------------------------------------------------------------------------
>>
>> \2\ In this context the word ``information'' does not include
>>information of a constant, unvarying nature such as is provided by
>>standard frequency emissions, continuous wave and pulse radars, etc.
>>
>>...
>> (2) Telegraphy--for aural reception................................ A
>> (3) Telegraphy--for automatic reception............................ B
>>
>>(Also see 2.202 for the bandwidth designators which precede the
>>emission type designation.)
>>==========================================
>>
>>--
>>martin.ewing@gmail.com
>>http://blog.aa6e.net
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>
>
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