C 0 H E R E N T C. W.



Alist of articles collected by MM which are of use to amateurs who would like to experiment with Coherent C.W.

Arevised list deleting many items on the previous list which are of little use bringing the 'list up-to-date.

Where circuits have been built additional notes are included correcting any errors found and giving further information which may be
'iseful.  Photocopies are ten pence per pace.  Information on circuits tested is given in good faith and thought to be accurate.
Should any errors be found it would @e appreciated if G3IRM could be notified so that any necessary corrections can be made.



Coherent CW - the concept by WHEY from QST for May 1981.
C

          Basic details of the theory behind the system - more complete than given in the A.R.R.L.
          handbook.



Coherent C14 - the practical aspects by W6XEY from QST for June 1981.
     This is the second part of I above and contains circuits for a complete CC19 station.
     As the design is several years old it can now be simplified and a revised frequency
     divider circuit is included.Additional frequencies are provided for use with the
     VE30BE keyer listed below andfor possible use with an r.f. synthesiser using an MC145151.

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Coherent Cld - the cw of the future by KBEEG/O from CQ for June 1977.
          A good basic article on theory which contains additional information and circuits not
          given in the W6NEY articles.   Note that none of these circuits has been tested.



4.Coherent Cli - the cw of the future by K8EEG/O froii CQ for July 1977 - part 2 of item 3 above.
          Contains some additional circuits but is basically the same as the WHEY article.    Note
          that none of these circuits has been tested.



5.Compact keyboard generates CW by VE30BE - publication unknown.
          This design for a morse keyboard can be synchronised to the station standard at 5 Hz.
It can also be used as a cw keyboard though provision for stored messages has not been
included. A ready programmed ros is available though the article includes a hex listing
for those who can program their own devices.



Source program for the VE30BE keyboard.
          Space is available in the keyboard ro3 for the addition of messages should anyone like to
          try to modify the program.



7.New frequency standard by VE30BE published in Northern Observer Newsletter (Canada).
          A very simple 4 MHz temperature controlled frequency standard for which a high degree
          of stabili7  is claimed.   For CCW use all references in the article to the Williams

               ty
          synthesiser should be ignored.



8.Extracting stable clock signals from a.3. broadcast carriers for amateur spread-spectrus
applications by HICK published in QEX for October 1987.
          A simple way to remove modulation from a.m. signals to obtain jitter free clock pulses.
          This has been used successfully to remove the modulation from Droitwich in a frequency
          standard.The original circuit obviously needs alterations to circuit constants in this
          application.An oscillator is locked to the carrier and can be used to produce
          multiples ofthe original frequency.



9.Fundamentals of CCW by Ray Petit W7GHM.
          Ray Petit was largely responsible for the introduction of CCW and this is one of the first
articles he wrote on the subject though much of it has been repeated in the QST and CQ
articles mentioned above.



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10.Coherent Ten-Tec by WA7ZVC.
          original article which is referred to in the A.R.R.L. handbook.



11.Frequency synthesised local oscillator system for the high frequency a;ateur bands by Petit published
     in Haii Radio for October 1978.
          Uses 14 i.c1s. and covers 5.0 to 6.0 MHz in 100 Hz steps or 1.1 to 1.6 MHz in 10 Hz steps.
          Requires a 1 MHz standard (not included in the article).   Tuning is by b.c.d. switches.



z standard (not included in the article).   Tuning is by b.c.d. switches.



12.The GGSO collection.
          This is a set of four diagrams used by Bob Carter. The first sheet is an r.f. synthesiser
and uses an MC145151, a CA3140 and six transistors-on 7 MHz, It is easy to adapt the
circuit for coverage on 5 MHz for use with a 9 MHz filter. A single b.c.d. switch covers
the I KHz steps with a single pole switch to give an additional 500 Hz shift if needed.
It locks to the standard on 8 KHz via an additional divider on the audio board. Two
further sheets cover the audio synthesiser and require eleven i.cls. and just two
transistors. The fourth sheet is simply a replacement for the 74C74 devices used in the
Woodson article as quadrature generators.   It replaces each 74C74 with a CD4013. If you
would like a brief data sheet on the MC145151 add 2 pages and the Cirkit design sheet on
which the r.f. synthesiser is based adds another 4 pages.



13.CCW circuit boards by 21M.

          The late Kurt Arlt has produced circuit board layouts for the W6KEY filter. For those who
          can make their own boards there is a set of double-sized layouts available.



14.All about Henry by WB4DCV from 73 Magazine for November 1988.
          This is a simple circuit for measuring inductance using just one IM311 and a transistor.
The circuit requires a digital frequency meter reading up to I MHz and a computer to
calculate the inductance. The basic program included is so simple it can be used on
any machine.



15.High precision standard from 73 Amateur Radio.
          This design uses a pick-up loop to lock the standard on I MHz to the U.S. NTSC TV standard.
It uses circuits very similar to those used to lock oscillators to the European long wave
stations.



16.K4EFU frequency standard from Hat Radio for February 1974.
          This is the original frequency standard used with the Petit filter and uses a 4 MHz crystal
in a temperature compensated oscillator. The original divider chain can be replaced by
more modern devices reducing the component count.



17. A Receiver Spectral Display Using DSP by Bill de Carle VE2IQ from QST for January 1992 - also AM
        Handbooks for 1993 and 1994.
The siqma-delta board for the analyzer proqraa and for COHERENT.



18.Software package - 'A receiver spectral display using DSPI by VE2IQ.
          The text file that comes with the display disk.



19.A DSP Version of Coherent-CW (CCW) by VE2IQ from QEX for February 1994.
          The article describing the COHERENT program.



20.CCW Using DSP and your Shack's Computer by VE2IQ.
          The text file that comes with the COMM proqra3 disk which includes interface connection diagrams.



21.Notes on COHERENT Version 2.3 by VE2IQ.

          These notes describe the slow speed and G3IRM modes included with the latest
          experimental disk not yet released.



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