I= - (_:@ - LAJ - f,,,j 4EE@ " 1'. SS __=S t-IL f__ t5 c-- c=) nn ra 3- 1 e-- cl t:3 (:3 31 F!;: 1-1 Corrections :::: I_ John Stace has drawn my attention to an error on the diagram for the up/down controls of the audio synthesiser - sheet number II. One of the outputs was given as pin 14 - it should obviously have been pin 11, Information sheet 26 is from the July/August 1988 issue of Elektor and not 1969 as stated. New members :::: GOHIN Toe Hamilton 67-SBI Colin Horrabin Frequencies :::: " at It seems to be generally agreed that we should use 30 up from the bottom edge of all bands and that least for the time being, channels should be spaced at I KHz above and below this frequency. It is most unlikely that there will be so many stations active that any other arrangements will be necessary for a long time to come. 7 and 14 MHz sees to be the most popular choices (also confirmed in Ray's survey) with 10 MHz as an alternative. New developments :::: I must give pride of place this time to some Yery interesting proposals put forward by Colin 63SBI. He is fortunate in having access to equipment for programming electronically programmable logic devices (EPLDs for short). He has already programmed an Intel BC060 as an iambic keyer which is synchronised to the station standard using the I KHz output.The device tc@ether with a few resistors and capacitors sakes a very easy to build keyer which is ideally suited to CCW.It is expected that the chips can be made available for about Es each ready programmed and Colin would like to knowwhat interest there is so that he can decide if it is worthwhile getting 25; or so devices in stock. If you would like to buy the i.c. please let either me or Colin know. In the meantime, if any of you can get hold of an Intel SCO60 or an Altera EP610 Colin would be prepared to program it for You. And this is not all. Colin has also programmed the same device to act as an audio synthesiser which should be suitable for use with the Petit filter. When this has been proved to be satisfactory he intends to try and get a Petit filter into the same type of chip so as to produce almost a complete CCW station in three chips. The standard and possibly the integrators will still have to be provided -separately. His aim is to produce a small add-on box which can be used with a commercial synthesised rig on CCW. This is just the sort of thing we want to get the system up and running. I have alwav5 thought that the reason CCW did not become popular in the early days was the fact that all equipment (which was quite complicated for the average constructor in those days) had to be hose built. Colin's proposals could well be the answer. Again, if these chips can be produced plEasE let us 'Know if you would be i@@ar.cfm,4 - -11 types would be about EB to 110 each. Colin's address is 11 Duckworth Grove Padgate Warrington WhQ 09U Ray Petit survey :::: Just as I was oetting ready to print this newsletter I received a letter from Ray giving I I the results of his survey. There were 10 replies. From these Ray says he was impressed by the level of technical competence shown by the replies. Most say they would prefer article- with schematics and some ask for p.c. board layouts. The acre advanced ideas put forward were popular though the very advanced ones appear to have been a little beyond some of those who replied. Ray no" proposes to write an article or a series of articles an second generation CCW. When these are available I will sake photocopies in the same way as I have done in the past so those who are interested can have them and no time and expense will be wasted on those who are satitiied with the present arrangements. CCW signal generator :::: The original generator - sheet no. a - was something of a makeshift though it did serve the purpose for which it was intended. I now have a new version using just four chips (five if you haven't got a 10 Hz output on your standard) which produces sine waves in place of the square waves generated by the original version. If you want a copy of the new circuit let se know or, alternatively, ay own is available for loan. If your filter is ready for testing why not just borrow mine and save having to build something which will probably never be used .@Oain. Petit filter :::: e i i er : : : : As 74C74 devices sees to be hard to find you say have been tempted to try 74HC745. don't seeft to work in this circuit. Most logic devices can be obtained in the U.K. from Viewcoa whose price list Don't, they just and address can be found in all issues of Elektor Electronics. If you have difficulty in setting the balancing potentiometers in the integrators try adding 100n from the two supply lines to earth as near as possible to U12 and U16. This has made a significant improvement in two filters tested. R.F. synthe5isers :::: His anyone been trying to build a simple synthesiser for 7030 KHz locked to the standard? My own efforts have centred around the Motorola MC145151. Cirkit sells a kit using this chip and there was an article in Elektor Electronics for July/August/Septeeber 198B using another member of the Motorola family. Apart from the method of programming the frequency required the device is very similar to the MC145151. The circuit I have used has worked nicely with just one small problem. I tried using an ex-or gate to change frequency by I KHz to give the offset between transmit and receive. However, there was a delay in changing over which rules out the possibility of key controlled changeover. I as still working an it but would be pleased to hear from anyone who is trying similar methods or would like to try them. If you are interested let me know if you would like a copy of the articles mentioned. Information sheets :::., 28.Audio output stage The output from the Petit filter needs amplifying for loudspeaker use. I have a simple circuit which acts as a low pass filter followed by an LM386 audio.output stage. The filter replaces the capacitor/resistor filter in the Woodson circuit. Q page) 2?. The 63SBI keyer Preliminary details of the keyer circuit. (I page) Updated details will be sent with devices purchased. Clover :::: Ray Petit has let se have a copy of his article which was submitted to GST but returned. This has been sent to the RSGB but, as yet, I have not heard whether or not they intend to publish. Yeroboard :::: Yeroboard can be used at r.f. with care. First cut the board to size and then solder a piece of wire across all tracks at one edge of the board. Assemble the first stage leaving as many tracks complete as you possibly can. Don't use a drill to cut tracks but cut across between holes with a knife. If you need two sections of copper two holes long keep these in the sane strip of copper instead of using adjacent strips. Make the solder pads just the size you need and don't leave long runs which are not needed - cut off the spare and pick the isolated piece up with the earth connections. when the stage is complete solder another piece of wire across all strips picking up any isolated unused pieces of copper. Build the next stage the same way and surround this with copper wire or earthed tracks so each stage has its own earth run all the way round. Make connections between sections with wire on top of the board. Finally solder a wire across all the earth tracks at the end of the board. Screens can be added above the earth runs. News from members :::: DF3CF:In his latest letter Bernhard says he is still progressing and hoping to get the audio synthesiser built soon. FILCI:Jean now has the basic data sheets so could be starting building. GOFVE:Other things have occupied Maurice but he says he hopes to start building later in the year. 63CCH:John has started a receiver using the 'MLX' board and has completed the audio synthesiser - hope it works. He now has all items completed with the exception of the rx/tx. 636RT:Bill now has the de Carle keyboard roe so should have a working keyboard. 63IRM:Most of ay activities are mentioned above - the r.f. synthesiser is still causing trouble but progressing, As a late item I might mention that I have another r.f. synthesiser working using an MC1648 together with my old favourites the CD4046 and the CD4059 though the output is not up to the standard I would like but it does switch I KH, easily! 63RHI:Bert now has a 63SBI keyer chip to play with - he agrees with se that it is suitable for CCW. 63TFV:Ed is still trying to get his receiver completed. W764M:Ray reports on-the-air tests of Clover with AKOX. Results have varied but on one run the receiver was correcting 10 to 155 errors in every 20-second block of data and delivered error-free data at 50 bits/sec. He no* hopes to try a 5000 Ks path to Jack ZFIHJ. All for now 73 de KIRM