COHERENT @ C.W. @ INEWSLETTER., Compiled by G31RM Issue number 19 Publicity The last note in CEX brought two enquiries but neither of these has so far resulted in a definite application for membership. My short article in the RAFARS journal CRV has produced five enquiries and four applications for membership, Commercial transceivers I think there is no doubt that the Kenwood TS450 and similar models can be used on CCW. I have added a Teledyne u.h.f. relay to mine in the space where the optional TCXO should go. This is controlled by the switch that turns on the CCW filter. There is only about a 40 Hz difference between the frequency derived from the internal oscillator and the external standard and the internal one seems to be remarkably stable. I feel almost certain that it would be suitable for CCW ff set to frequency which confirms my earlier thoughts that the optional TCXO will certainly be suitable. The TS430 appears to be much more difficult although ft looks as though it would be easy. This has been confirmed by Bill de Carle who usually seems to come up with something whenever I raise a query. He converted his some time ago. One of the problems is that the 800 Hz offset is not generated digftally and a whole lot of circuitry had to be added for the conversion. Another funny thing about the 430 relates to tuning. You can set the frequency with the tuning knob to a figure shown on the display and you may or may not be on that frequency. It can be off frequency by one or more steps when the knob is used. The fix is to enter the frequency into memory with the push buttons and then recall it when you will be sure that the display means what it says. Bill finally tracked this down to a bug in the microcode. Apparently Kenwood refused to do anything about it so Bill re-wrote the code himself! He also has a Kenwood TS850 which is similar to the 450 and he considers this is also suitable for CCW. I have mentioned before that Kurt OE1KYB has September 1992 converted a TS940 but this, like to 430, needed a lot of work. Cliff W6HDO is also looking into the possibility of using other commercial transceivers for CCW. The more that we can prove are, or are not, suitable the better. For those who have suitable commercial equipment this is definftely the way to go though conversions of older transceivers can be carried cut. I think the popular Heathkit HW7, 8 and 9 should all be candidates for conversion though probably only to one or two fixed frequencies. The provision of suitable transceivers has, I think, always been one of the reasons why CCW did not become popular. The more commercial equipment that can be proved to be suitable the better chance we have of making the system more popular. Automatic morse decoding Automatic decoding has always fascinated me ever since I built my first mechanical decoder in about 1950. 1 still have an ex-RAF syphon recorder. Since then I have built digital decoders, written decoder programs and tried out every mcrse decode program I can find on machines like the ZX81, Spectrum, Acorn, Einstein and PC. I recently came across what I think is about the best. It is called CWD and is by Robert R. Anderson K2BJG. The version I have is number one (for the PC) so there could be more recent versions. Unlike many of the others, it is written in machine code (which I like) and has all the facilities I want and none of what I consider to be unnecessary frills. It is shareware so I can copy the disc. If you would like a copy let me know what size disc you require. I can do either 3.5" or 5.25". To run the program you need an interface to the RS232 port and guidelines are given in the notes with the program. My own interface works faidy well and I can put notes and circuit together for anyone who may want to try. Incidentally I wonder why these people who write programs using the RS232 port do not use the same pins for the same purpose. I have thre programs which use different pins for the interface output to the computer - it would save a lot of bother if they all used the same. Droitwich For a long time I tried to use this transmitter on 198 KHz as a frequency standard and never did convince myself that it was satisfactory. I am now certain that it isn't. If you listen to the station in the SSE3 mode you will hear a distinct warbling on the note caused by frequency modulation. This has something to do with what is known as a radio teleswitch. If you want to know more look at page 58 of the RSGB's RadCom for August 1992. For some unknown reason the standard I built using Droitwich, and which includes a synchronous oscillator, works as a standard but does not appear to be suitable when other oscillators are phase- locked to it to control a transceiver. I now feed the output from this together with the output from my TCXO into a Motorola phase detector fitted with two Le-d's. When first switched on both light as the TCXO is well off frequency. After a period of time one starts to blink on its own indicating that the frequency of the TCXO is either high or low in frequency. It takes about forty minutes for the TCXO to stabilize and thereafter a slight variation of the TXCO frequency causes one or other of the I.e.d's. to dim slightly but they both stay lit indicating a high degree of accuracy. I could never get this accuracy when using the Droitwich standard. A TCXO is the way to go. Clover Still nothing new to report. 10 MHz Cliff W6HDO has indicated that he thinks that E layer stability may be a problem when using 20 metres and suggests that, in any tests with his side of the Atlantic, the use of 10 MHz would probably be better. We must bear this in mind when we get to the stage of transatlantic contacts. Possible tests Cliff's thoughts of trying a kilowatt of CCW for short periods on 7030 do not appear to have been received with very much enthusiasm in his part of the world so he is trying to think up some other alternative. During the next few months I intend to call Co CCw on as many Thursdays as I can at 2030gmt on 7030 for about five minutes for testing purposes. Transmissions will, of course, be at the 1 OOmsec bit length and should anyone call either as CW or CCW I will answer. I hope that those of you who have a working CCW filter will try and resolve the transmissions. M2iling list 3A2LY @'GONSZ @@:G:31VR.. :.::-AKOB:@:: G.00YX::::-G4DWC DF3CT@ G3CCH @@G4FKH @CrElATU@: @TG7YFW@MCWW@ G4GMV QEIKYB:@ DJ3AM:@ G3EGQ G4HCC OZ5CFM@ DJ4SB:@:@@G:3:FMW:@: G-4LRA@: -OE6WTD:: @DJ7HS G3GRT: G40KO OK3EW:@:x: DJ7PO@ -@G3IGH::@ G4PUQ@.:.:SM6FPC,., DK1IO :@G3IRM:@:G4SYC:.. @VE.21Q@ DL2AAX G3JPP::@:G4VS-0 :VE313PB:::@@:@ DL2RK@@G3MBR@@:G4XOPi:@ W6HDG::::@:@::@ tX8 Yu@,G-3MND::: G4YND@::::47 ............. @:@GGFVE @=H1:@ . :@G=X@:: T4UOj: G:3 SRI GWGKSW::Y2:3V1!::" G3TFV@:@::@,GW3DEX':Y:24Xb'@:'. :.@.GQIYY .:G3TMQ:@.:.HB9DDO:::Z?...... :J. ::::::.: .......... ........... :@GOXIF:G3XHQ:::xK6AR There are several other amateurs who read the Newsletter but they are not listed here as they receive copies from members. If you want to hand on copies to anyone interested please do so. The VE21Q Spectral Analyser Bill de Carie's design for a receiver spectral analyser appeared in the January 1992 issue of OST. It uses nine fairly common i.c's., a crystal and very little else. A nine volt battery will supply power, the input comes from the receiver and the output goes to the RS232 port of the PC. I can supply more details if you are interested but please note that the following advertisement gives postage for Canada and U.S.A. only - postage outside these countries will be slightly higher. Final comments Please let me know how you are getting on and if you are anywhere near ready to operate. Again let me say that it would be a great help if you could look at any commercial equipment you may have and decide if it can be used for CCW and what, if any, alterations are likely to be required. 73 de G31RM