W6IWI RTTY Notes
The photos above show the RTTY hardware. The left photo shows, left to right,
the Teletype model 15KSR printer (Signal Corp order number 14700-PH-49, serial number 793),
the model 14 Transmitter Disbributor (tape reader),
the loop patch boxes, and, on the right, the model 14 Typing Reperforator (Signal Corp. order number 3357-PHILA-52).
The last two digits of the order number indicate the fiscal year of the order. Therefore, the printer was delivered in about 1949,
and the typing reperf in about 1952. The
middle photo shows the loop patch boxes. Each is a 4x4 electrical box with a blank
cover. Four 1/4 inch Tip Ring Sleeve jacks are mounted on the blank covers. The
jacks have a switch that shorts tip to ring when nothing is plugged in. The tip and
ring connections are all wired in series. The box marked TU is connected to the
Flesher TU-170 Terminal Unit. Any device plugged into one of the
jacks on this box is inserted into the loop driven by the TU. The model 15KSR printer
and 14TD are typically plugged into this loop. The other patch box is driven by a
152950 loop supply with series 2.2 k current limiting resistor
seting the loop current to 60 mA. The right photo is the
Flesher TU-170 Terminal Unit with a
WAVE 2 scope on top as a tuning indicator.
When not being used for something else, the
station is on the Green Keys autostart frequencies listed below.
|Frequency Type|| Day (MHz)
|Space||14.083,705||7.083,705||Space is 170 Hz below Mark|
|US LSB||14.086,000||7.086,000||Mark tone 2.125 kHz, Space 2.295 kHz|
|US LSB low tones||14,085,150||7,085,320||HAL ST-6000 low tones. Mark 1.275 kHz, Space 1.445 kHz|
|Center||14.083,790||7.083,790||Shift up 85 Hz for Mark,
down 85 Hz for Space|
|Navy MMM LSB||14.085,490||7.085,490||Mark tone 1.615 kHz, Space 1.785 kHz|
|Navy LF LSB||14.084,790||7.084,790||Mark tone 915 Hz, Space 1085 Hz|
|Europe LSB||14.085,830||7.085,830||Mark tone 1.955 kHz, Space 2.125 kHz|
- Green Keys mailing list. A bunch of
- Internet Teletype - Three AFSK streams
to feed your Teletype!
- RTTY Audio - Test signals received on the KFS SDR exhibiting fade and noise. Use to test terminal unit demodulators.
- RTTY Sub-Bands - Suggested
- The New RTTY Handbook - Scans from The New RTTY Handbook, 1971
- RTTY Journal - The RTTY Journal was first published by the Southern California Radio Teletype Society as the RTTY Bulletin in January 1953. Over the years, the name has changed to RTTY Journal, RTTY Digital Journal and The New RTTY Journal.
- ARTS Bulletin from the Amateur Radio Teletype Society.
- The Teletype Story - 1957 brochure describing the history of Teletype Corporation.
- The Start of Amateur RTTY - EXCELLENT history by Jim Haynes.
- Heavy Metal RTTY. My presentation to the Boat Anchor forum of the
Long Island CW Club and the Radio Society of Tucson.
- RTTY Electronics, P.O. Box 20101, El Sobrante CA 94820. Phone +1 510 222 3102. Email
email@example.com. EXCELLENT source for
Teletype parts. photos,
- Loop Supplies
|152950 150ma $20.00 - This is the supply I am
using on a local
loop. It is a small open
metal chassis with a transformer, a couple silicon diodes, and a capacitor.
It has a D-hole that accepts an HKP fuse holder. I added a fuse holder,
a line cord, and a terminal block for the DC output. When driving the loop,
the voltage is 125 VDC. A 2.2k 10W resistor sets the loop current to
about 60 mA. The voltage across the resistor is 122.7 VDC for a loop
current of 55.8 mA.
- 162361 500ma $30.00
- REC29 200ma $35.00
- Teletype model 14 Transmitter Distributor
- Teletype model 14 Typing Reperforator
- Teletype model 15
- Ribbon Re-Inker Kit - My notes on the re-inker kit.
- Cleaning type slugs
- Clean with alcohol and "brass toothbrushes" Amazon,
Digikey. They can get ink out of the typefaces, but are not
hard enough to take the Parkerizing off the typebars or scratch steel.
- Model 15 Slow Motion Video
- Teletype Videos - Great series of videos on how a
model 15 works
- Sychronous Motor Measurements - The mechanical load on the motor varies
with machine adjustment (such as clutch tension) and lubrication. There is
more load on the motor when the machine is idling since the clutches are slipping.
Here are the measurements on my model 15. The "running" column is with the
space bar held down so the keyboard and printer clutches are released.
|Current||2.5 A||2.48 A|
|Power||79 W||70.5 W|
|Apparent Power||297 VA||293 VA|
|Power Factor||26 %||24 %|
- RTTY RATT Radio Teletype - Extensive historical documents at
Southwest Museum of Engineering, Communications and Computation - Includes copies of
the journal of the Amateur Radio Teletype Society going back to 1946, a history of HAL Communications, and lots of other interesting info.
- White roll
, 235 feet. $11.75 each for 3+
- Iconex 90742200 - Roll of
8.44 inch wide by 235 feet long. $11.15 per roll with free shipping.
- PM Company® Teleprinter Paper Roll, 8 7/16" x 235 ft, White - $9.64/roll
- POS Supply - 8 7/16 inch by 225 feet, 12 rolls for $78.95 with free shipping
- 2,700 Sheets 8.5 x 11 One Part - One Ply White 20 #, Heavy Weight, NO SIDE PERFORATIONS, Continuous Stock Computer Paper - $44.97
Furuno PP510/520 1 Ply Telex Paper 214MM (8.4IN), $12.95 per roll,
- Adorable Supply - Variety of roll paper with
- W2JC has paper, tape, ribbons, manuals, and more.
- Paper Tape - 11/16 inch paper tape for model 14/19 reperforator
- Ribbons - Same ribbon used on model 14 typing reperf and model 15 page printer.
Swartz Ink SI-83-BKTE, also on
Amazon, package of two (each includes two reels and reversing
rivet), $7.00 + $4.99 shipping. The inking of these ribbons seems light to me.
They gve faint but very readable type on the model 15 printer. The type on the
model 14 typing reperf is quite light and difficult to read.
- Ribbons Unlimited
33P, $11.95 plus $4.99 flat rate shipping
- W2JC has paper, tape, ribbons, manuals, and more.
- Baco Ribbon, +1 314 835 9300
- Printing Telegraph History
- PRINTING TELEGRAPHY ... A NEW ERA BEGINS, Edward E. Kleinschmidt
- Hell Feldfernschreiber teleprinter - A very clever dot matrix teleprinter. The transmit side
transmitted vertically scanned pixels. The receive side uses a two turn helix to provide vertical scan and moves the paper tape to provide horizontal scan. The helix is
inked by a saturated felt. A solenoid operated knife edge under the paper presses the paper to the inked helix when a pixel is to be printed. The two turn helix
is very clever. Because of it, no synchronization is required between the transmitter and receiver. If the transmitter and receiver are perfectly "synchronized,"
the text appears on the tape as two rows of characters. If they are not synchronized, one complete line of text is on the tape with the other line split above and
below the good line (it wraps from the top edge to the bottom edge). But, there is always a good line of text. If the speeds of the transmitter and receiver are
slightly different, the text drifts towards the top or bottom of the tape, but a complete line is always printed.
A similar printer is described at
Tape Facsimilie. With the Hell Feldfernschreiber,
a keyboard generates the pixel pattern while the
Tape Facsimilie uses optical scanning of tape with a hand written message on the transmit side.
- First-Hand:Chad is Our Most Important Product:
An Engineer's Memory of Teletype Corporation by Jim Haynes. Fascinating personal history of Teletype.
- Terminal Units
- Flesher TU-170 Terminal
Unit - My notes on the TU-170
- DSP Terminal Unit - My notes on making a DSP-based terminal unit using a PIC32MZ microcontroller. The perfect combination of old and new!
- TU Comparison - A table under construction describing demodulators in some terminal units.
- TU Notes - General discussion of terminal unit design, espectiall the demodulator.
- TU References - A look at about 100 years of discussion of terminal unit design.
- Droid RTTY - Great
Android application that transmits and receives AFSK RTTY.
- Bytheway Software Development Lab (BSDL) Software Library - Software specifically written for RTTY and the BAUDOT
code by K7TTY
- RTTY Demodulator for Linux - Mark and space bandpass filters drive subtractor
which drives a zero cross detector. Latest version also decodes packet and CW.
- Linux command line to copy ITTY
curl -N -s http://internet-tty.net:8000/ITTY | lame --decode --quiet --mp3input - - | minimodem rtty -i -a -q --rx-one -R 11025 -f -
- MMTTY - Teletype terminal and modem
in software. Runs under Windows and drives transceiver through sound card. Also on the
site is MMSTV for slow scan television
- Ham Radio Deluxe - Have had several QSOs with people running this software. It appears to work well except that
people rarely send CR and never send LF. Ideally people could type control-J to send line feed, but they would have to remember to do it. Don't know if that
actually would send a line feed.
- KiwiSDR - A software defined radio with web server that supports multiple users. Includes CW and RTTY decoding.
- KiwiSDR Mapr of receivers around the world
- Link to KFS (Half Moon Bay CA) KiwiSDR tuned to 20 meter RTTY autostart frequency with RTTY decoder selected
- JNX decoder that is the basis of the RTTY decoder in KiwiSDR.
In particular, JNX uses a bandpass filter for mark, another for space, squares the output of each, subtracts the results, low pass filters, then compares the results
to zero for determining mark or space.
- Configuring Software to send CRLF - How to configure various RTTY software to properly send carriage return and line feed
to avoid overtyping on real Teletypes.