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4.3  DEMODULATOR:

The  proper  demodulator  circuit  is  automatically  selected  when 

changing modes.  The dual tone (mark and space) is for RTTY and the 

800HZ  single  tone  decoder  is  for  CW.  You  can,  however,  manually 

override this selection by typing ‘CTRL N’ (not recommended), which 

forces the unit to copy only one tone,  mark or space,  not both.

The  on-screen  tuning  indicator  tells  you  which  circuit  has  been 

selected.  The cross pattern is  displayed for  dual  tone  (blank with  no 

signal)  and a red dot is used for single tone.  The red dot should stay 

“on” in RTTY.  If it goes out,  it is an indication of signal  drop out or 

mistuning.  In addition,  the copying logic can be inverted by typing 

‘CTRL  -  ’  (minus).  Similiarly,  ‘CTRL  + ’  (plus)  returns  to  normal 

select.

4.4  PUBLICATIONS OF INTEREST

“RTTY TODAY” by Dave Ingram
“World Press Services Frequencies” by Thomas Harrington
“Worldwide Radioteletype Stations” by Klingenfuss

All  published  by:  Universal  Electronics,  1280  Aida  Drive, 

Reynoldsburg,  Ohio 43068

“Confidential  Frequency  List”  by  Oliver  Ferrell,  published  by 

Gilfer Associates, P.O. Box 239, 52 Park Avenue, Park Ridge, NJ 07656.

4.5  RADIO TELETYPE FREQUENCIES

The following is a short list of some of the more regular and easy to 

copy RTTY stations around the world along with frequency ranges to 

explore.

4.5.1  Amateur Radio RTTY
BAND

FREQUENCY

TIME

COMMENTS

80 M

3600 — 3670  KHz

Night

All “narrow” —

40 M

7070 —  7100 KHz

Night

most use 60 wpm

20 M

14070 —  14110  KHz* Day/Night with some  100 wpm

15 M

21075 — 21100 KHz Day/Night Baudot code

*most popular

4-4

Summary of Contents for SWL

Page 1: ...RADIO INTERFACE CARTRIDGE FOR THE COMMODORE C B4 Complete terminal with software inpermanent ROM for Receiving RTTYand MORSE Code MICROLOG SWL MICROLOG CORPORATION 1986 ...

Page 2: ......

Page 3: ... you tune your radio in the SSB CW mode or with the BFO on the sound you hear varies in pitch frequency The SWL detector circuits are listening for tones around 800 Hz about 1octave above middle C By moving the tuning dial on your radio you can adjust the sound for exactly the right pitch Simply watch the on screen tuning indicators or use the pitch reference tone heard through your video monitor ...

Page 4: ...ind some ASCII in the amateur radio bands but even there Baudot is most prevalent This is the code that the SWL will copy when first turned on 0 1 2 Speed There are 5 standard speeds of Baudot 60 66 75 100 and 132 words per minute only two of which are in common use Amateur operating is usually 60 wpm Occasionally you ll find a little 100 wpm Commercial RTTY is usually either 66 or 100 wpm 0 1 3 S...

Page 5: ... listening post 1 Don t use the radio s internal whip antenna or a short wire 10 20 tied directly to the external antenna input The close proximity to the computer and relative inefficiency of the short antenna combine to almost guarantee you ll hear some computer noise Use coaxial cable RG 58 U available at Radio Shack to get the antenna out of the near field of the computer Make the antenna as l...

Page 6: ...or will be displayed in the left center of the screen in white The receive text cursor will be at the bottom left screen in yellow If using a monochrome black and white TV monitor colors will appear as shades of gray In the event that the above does not appear on your video monitor s screen check the cable between the computer and the TV monitor to make sure that it is not shorted or open You may ...

Page 7: ...me until the SWL starts to copy the text from the tape and display at the bottom of the video screen Don t turn the volume up too high because itwill overdrive the SWL stone detector circuits and make mistakes in the copy Make sure the nar wide switch on the SWL is in the wide position 1 2 ...

Page 8: ...down the CTRL key and while holding it down press the X key then release both keys Similarly to type or press SHIFT X means that you should hold down the SHIFT key and while holding it press X As soon as the X key has been pressed you can release both keys After familiarizing yourself with the location of the various sym bols on the keyboard type some Alpha Numeric text Observe that the characters...

Page 9: ...des as shown on page 139 of the 64 manual with one exception To utilize a single digit for all 16 colors you must enter it in Hexadecimal that is 0 through F instead of 0 through 15 The colors are as follows 0 Black 1 White 2 Red 3 Cyan 4 Purple 5 Green 6 Blue 7 Yellow 8 Orange 9 Brown A Light Red B Dark Gray C Med Gray D Light Green E Light Blue F Light Gray The colors will change upon typing the...

Page 10: ...ual text as it is sent The text which is displayed above the line represents the entries into the system s text buffer Return the system to the receive mode with the RUN STOP key by itself or by typing CTRL CLR HOME hold the CTRL key and press the key labled CLR HOME Observe that the top line display has changed indicating that the system is in the Receive mode Type in some text and note that it i...

Page 11: ... to 110 BAUD when ASCII is selected Observe that the top line displays A 110 BD BAUD where the A in dicates that the selected code is ASCII To select an RTTY ASCII rate of 300 baud no need to type CTRL A since you are already in ASCII TYPE TYPE TYPE CTRL X 300 CLR HOME Note if you are in 300 BAUD ASCII to change to any other speed or code you must first go to 110 BAUD ASCII The jump from 300 BAUD ...

Page 12: ...ou will hear the MORSE code as it is displayed below the split line To change the speed use the CTRL X command Also when the text buffer is empty if desired the MORSE equivalent of a diddle BT can be sent Type CTRL D to toggle the diddle mode on off To select a MORSE speed of 17 words per minute TYPE CTRL X TYPE 17 NEW SPEED TYPE CLR HOME OR ANY NON NUMERIC KEY Observe that the newly entered MORSE...

Page 13: ... buffer by means of the CTRL C command Type CTRL C and observe that the clock time is displayed on the lower half of the screen if you are in the text mode If you turn up the monitor volume you can hear the code being sent 2 7 MEMORY STORE RETRIEVE COMMANDS The SWL includes a number of user programmable memories These are useful for storing phrases and comments that are used often There are 8 mess...

Page 14: ...unction keys In a similar fashion you can store and retrieve messages from the other 7 memories If your message is longer than the selected number of characters it will simply overflow into the next message memory location For exam ple if you store a message that overflows into memory 2 it will be pro perly retrieved in its entirety by typing FI If you type F2 you will retrieve the last remaining ...

Page 15: ...D shown next to WRU This function is only used in the transmit receive version of this program See Section 7 2 for information on creating OFF THE AIR Receive Memory 2 8 TEXT MODE COMMANDS The program has a number of transmission modes In the CHARacter mode this is the system default mode each character is sent as it is typed In the WORD mode an entire string of characters is transmitted as soon a...

Page 16: ...epeat a segment of text by means of the key To repeat the printing of a text segment first type SHIFT press the SHIFT and keys This serves to point to the beginning of your text Now enter your text which will be printing if you are in the text mode Press the key and the text will be repeated Press it again and it will be repeated for the third time I i 2 9 ...

Page 17: ...vided be tween the EARPHONE or external speaker output of your receiver and the SPKR EARPHONE input on the SWL You will note that there are two SPKR EARPHONE phono jacks on the SWL These are con nected internally on the board This allows you to plug one cable from your radio to the SWL and one cable out to your external speaker or headphone eliminating the need for a Y connector Refer to the diagr...

Page 18: ... strong RTTY signal and listen to the received audio Your receiver should be tuned so as to produce tones around 700 900 Hz When the signal is properly tuned the on screen tuning indicator will flash in synchronism with the incoming audio tones The cross hatch tuning aid simulates the pattern observed when using an oscilloscope for tuning Proper tuning is indicated when a cross is displayed The Ma...

Page 19: ...ne display when in RTTY receive mode The actual software program operation of the ANCW is to in hibit the video display until 10 properly timed stop bits are received in a row If two stop bits are missed the 10 counter is reset and the display is disabled until 10 more stop bits are received in order The mechanical teleprinter keyboards that use the Baudot code have fewer keys than a standard type...

Page 20: ... some stations which are utilizing a non Latin alphabet such as Russian Arabic etc You will of course not be able to decode such transmissions You should however find numerous stations using the standard Latin character set with transmissions in various languages including English Commercial stations in general use a wider shift with 425HZ as the most typical Your NARROW WIDE switch should be in t...

Page 21: ...verted by typing CTRL minus Similiarly CTRL plus returns to normal select 4 4 PUBLICATIONS OF INTEREST RTTY TODAY by Dave Ingram World Press Services Frequencies by Thomas Harrington Worldwide Radioteletype Stations by Klingenfuss All published by Universal Electronics 1280 Aida Drive Reynoldsburg Ohio 43068 Confidential Frequency List by Oliver Ferrell published by GilferAssociates P O Box 239 52...

Page 22: ...Beijing Press China Rueters Press London Rueters Press London Rueters Press London Tass USSR Rueters Sydney Australia USIA News New York USIA News New York AP News New York Prensa Latina News Havana Cuba Czech News Prague Kokusai Osaka Japan Saporitinews B A Agrentina UPI Amsterdam Holland German News Berlin Indian Info New Delhi 14400 16500 KHz 18000 21000 KHz Frequencies Speed Shift 14901 KHz 66...

Page 23: ...order to decode properly the inter character spacing must be at least as long as two times the average element spacing 5 1 HAND KEY Before proceeding with on the air reception you may find it useful and instructive to experiment with a hand key if you know MORSE code otherwise proceed to 5 2 Receiving Connect a hand key to the HAND KEY jack on the rear of the SWL This should be con nected to the c...

Page 24: ...1 2 Thus when the top line displays a MORSE speed of 20 WPM it means that the system s current value for the so called average dot is 60 milliseconds All incoming code elements dots spaces dashes are then compared against this current average dot value as part of the decoding algorithm s decision process as previously described This average dot is continuously being updated based on the incoming c...

Page 25: ...tions up to about 50 Enable the SPEED LOCK by typing CTRL T You will also find that your receiver sCW filter is helpful in reject ing nearby signals from interfering with the reception of the desired signal The SWL includes a sharp 300HZ effective bandpass which is sufficient for rejecting undesirable signals Your receiver s AGC however may act in such a way as to reduce its gain due to a strong s...

Page 26: ... the printer HAND SHAKE Note that the SWL expects the Commodore printer to be DEVICE NUMBER 4 CTRL F3 function key 3 causes the Commodore printer to print oversize letters CTRL FI resets to normal letter size Once the Commodore printer is selected by typing CTRL V either CTRL V or CTRL P will act as the ON OFF toggle The last one selected determines which is enabled automatically by the P ON SEL C...

Page 27: ...RETURN You will then be requested to press PLAY and RECORD on your data set When memory save is finished the program will automatically jump back to SWL You can continue normal opera tion or shut down knowing your programmable memories are safe on tape for later When loading the memories go to BASIC aswhen SAVING then type SYS 32796 location of tape load routine RETURN Press PLAY on the data set W...

Page 28: ...to disk This can be a big help in archiving various broadcasts you might like to save Another practical use of this program is to store often used paragraphs name address etc that you want to include in a letter Since the SWL can access a printer it makes a very simple word proc essor Even with its limited editing function the capability to recall whole blocks of text mixed with direct keyboard in...

Page 29: ...uffer and return transmit buffer to normal size erase screen buffer and go to receive Ignore received carriage return code ON OFF toggle Change screen colors See 2 3 Horizontal screen shift See 2 3 Enter secondary ID text of up to 64 characters Follow the CTRL I by the desired text and ter minate by typing CLR HOME key Text will be entered into the text buffer for transmission by typing SHIFT No a...

Page 30: ...baudot space code 11011 will cause automatic shift to lower case letters mode Commodore serial printer enable disable toggle Displays V when enabled Word Mode ON OFF toggle Select operating speed Follow this command by the desired speed in WPM for MORSE or BAUDOT and in ASCII by the baud rate Changes current case during reception FIG to LTR or LTR to FIG No action Load memory FI Load memory F2 Loa...

Page 31: ...mputer operation To re enter AIR 1 communications mode type SYS command then RETURN key Not used in Receive Program Displav contents of WRU print on print off SEL CALS Restores Commodore printer to normal size print Causes large character print on Commodore printer Enables storage into receive memory buffer Disables stops storage into receive memory buffer The space bar and CTRL keys are pressed t...

Page 32: ...eceive if text buffer is empty Displayed as an up arrow Enable text mode Also enables text mode same as shift run stop Random code option selected System will cause 5 character random code groups to be transmit ted Press any key to deactivate Letters code in BAUDOT in ASCII transmit only Sends figures code in RTTY BAUDOT in ASCII trasnmit only Go to MORSE Action will occur at that point in text DO...

Page 33: ...Return and Line Feed Codes in RTTY Sends CQ_CQ_CQ_DE_ transmit only Sends comma in all codes Sends period in all codes in all codes 7 2 USING THE RECEIVE BUFFER MEMORY The SWL program provides for a 28000 character text buffer 14000 characters of this can be set aside for a receive buffer that can ac cept data directly off the air for recall or printing You must first create this new memory by typ...

Page 34: ...s the previously stored receive text Note CTRL F 5 F 7 do not control the printer only receive data storage To send data from this memory hit the key by itself The CTRL E command returns the text buffer to normal and disables the receive buffer memory 7 6 ...

Page 35: ...MICROLOG CORPORATION 18713 Mooney Drive Gaithersburg MD 20879 Telephone 301 258 8400 Telex 908153 ...

Page 36: ...SPEAKER EARPHONE HAND KEY NAR WIDE 170 425 CW 850 SWL MICROLOG 18713 Mooney Drive Gaithersburg MD 20879 ...

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