Msg#:22089 *SW ECHO* 02-18-89 00:38:00 From: GORDON EDWARDS To: ALL Subj: RTTY In appendix H of the owner's manual for the Hayes Smartmodem 1200, it says it may be connected to amateur radio equipment for RTTY or computer-to-computer operations. Best results will be obtained with AFSK but Direct FSK can be accomplished.... The book also gives the commands for making it receive 225 Hz mark, 2025 Hz space, and 1270 Hz, 1070 Hz space at 300 bps. It also gives the commands for receiving at 1200bps with a signal centered at 1200 Hz (bandwidth of 900 Hz)... Next it gives a diagram for connecting the wires in the telephone cable to the radio equipment. I use a Sony ICF-2010, and tried connecting the red and green wires to the audio output of the headphone jack on my radio. On the console connected to the modem, all it 'got' was a lot of continuous (sp) trash... Is the Sony capable of receiving RTTY??? Does my hook-up sound right??? The book also says: "The Smartmodem 1200 may also be used for 1200 bps radio communication. However, it is not compatible with the 1200 bps Bell 202 type FSK modems used by some radio amateurs. What baud rate is usually used for RTTY??? What is AFSK and Direct FSK? Next is an attempt at the diagram given: To smartmodem 1200 RJ13 "Telco" Jack Receive level control +----------- +-------------------+ ! ! ! ! ---------+ Speaker Output ! ! / ! ! ! (4) T <--------------+-\/\/\/\-> \ ! ! ! transmit / / ! ! ! level \ <-- \ ! ! ! control / | / ! ! ! (3) R <--- \ +-/\/\---+--------! Microphone input ! ! ! ! ! ! ! ! (5) A1 <--+-----------+------------+--------! Ground ! ! ! ! ! (2) A <------------------------------------! Push to talk ! ! ! ! +----------- +-------------------+ A, A1: Auxiliary relay contacts in the Smartmodem 1200. T, R: 600 Ohm audio lines. Output level -10 dBm, Input level should be greater than -40 dBm. Please excuse crudity of picture, done using the BBS editor. According to above, which wires should be connected to the audio wires from the headphone jack??? Gordon Edwards --- TBBS v2.0 * Origin: Atlanta Connection - Voice of Atlanta (404-929-0800) (133/205) Msg#:22148 *SW ECHO* 02-26-89 18:28:00 (Read 7 Times) From: STEVE CHOATE To: GORDON EDWARDS Subj: REPLY TO MSG# 22089 (RE: RTTY) Hitching the red and green wires from the phone jack on your modem to the headphone jack on your radio sounds OK to me. I've had some luck getting RTTY from my radio using this method. Your problem is probably that you are not using the correct baud rates or code. I don't believe that 300 baud ASCII is used on any shortwave bands. 110 baud ASCII is used some but most RTTY that I've received has been 45 or 75 baud Baudot, a five bit code. It's not hard to write a BASIC program to decode baudot if you want to give it a try. the ARRL Handbook has information on baudot or I would be willing to mail you a copy of a program if you like. you should certainly be able to receive RTTY on your radio . Any radio with a BFO will do ina pinch. Let me know if you'd like some more info. Good luck steve --- * Origin: PIONEER VALLEY PCUG #1 Amherst, MA (HST) 413-256-1037 (Opus 1:321/109) Msg#:22170 *SW ECHO* 02-27-89 09:21:00 (Read 5 Times) From: JIM VICKONOFF To: GORDON EDWARDS Subj: REPLY TO MSG# 22148 (RE: RTTY) There's a project in the 1988 ARRL Handbook for RTTY reception using a Bell compatible modem chip. It may help some. Good Luck....Jim --- Lynx v1.23 * Origin: Tranquility Base, NEC 143 (408) 251-4926 (Lynx 143/31) Msg#:22178 *SW ECHO* 02-26-89 16:11:00 (Read 5 Times) From: JOHN ROSS To: GORDON EDWARDS Subj: REPLY TO MSG# 22170 (RE: RTTY) FSK is "Frequency Shift Keying", which is a standard technique for transmitting intelligence by radio. Oh. Now what does that mean? It means that the signal is transmitted in two discrete frequency values (often called mark and space). Your radio should include something called a "beat frequency oscillator (BFO)" that converts the FSK signal to audible tones which your modem can recognize and convert to characters that your computer or terminal can print or display. That's the "225 Hz mark, 2025 Hz space" stuff in the Hayes manual. AFSK is Audio Frequency Shift Keying, which means that the mark and space frequencies are audio tones, transmitted on the same carrier frequency. It's an oversimplification, but that's what your modem uses to send and receive data to and from a telephone line. The word "Modem" is an acronym for MODulator/DEModulator. In this application, it's the Demodulation that you want to worry about. The modem is looking for audio tones at its tip and ring input, and it doesn't know or care whether the tones are coming through the air or through a wire. As for your hook-up, you're probably on the right track. You should connect the T and R (which stand for Tip and Ring) leads on the modem to the highest level audio output on your radio. Might be headphones, might be tape, might be something else. Try 'em all, I guess. Since you're only trying to receive and not transmit, you don't need to worry about the audio input level to the modem. If you're getting garbage on your screen, that's a good indication that your radio is probably connected to the modem properly. Now you've got to tune the radio correctly. And keep in mind that a lot of the RTTY data on HF is encrypted somehow--if you can read it at all, it will read as gibberish. I'm not familiar with your radio, but if it has a "BFO" switch or something similar, turn it ON. If there's a variable bandpass filter, set it to the narrowest setting (CW if it's available, otherwise try USB). I've seen some other messages on this echo from people receiving fax and RTTY on a Sony--can somebody help here? I can't tell you which speed settings to use. Whatever works. I hope this all helps. If I've left you even more confused than when you began, let me know and I'll try again. Let us know how it all turns out. --- * Origin: BECS Tandy OPUS (Opus 1:343/1) Msg#:22187 *SW ECHO* 02-28-89 01:19:00 (Read 5 Times) From: MICHAEL COVINGTON To: GORDON EDWARDS Subj: REPLY TO MSG# 22178 (RTTY) Connect the receiver output (speaker level) to the T and R terminals on the modem (i.e., the inner two of the four telephone wires, green and red). I don't know whether there are any signals you can decode; someone more knowledgeable about RTTY should be able to tell you. For starters, try decoding the 300 baud chirps on CHU (Canadian time signal station). --- QuickBBS v2.03 * Origin: -=< Athens FORUM Georgia >=< 404-546-7857 >=- (1:370/5) Msg#:22379 *SW ECHO* 03-02-89 21:46:00 (Read 6 Times) From: GORDON EDWARDS To: DOUG SMITH Subj: REPLY TO MSG# 22378 (RE: RTTY) From the Hayes Smartmodem 1200 owner's manual: Commands to receive 2225 Hz mark, 2025 Hz space: Enter: AT S10=255 C0 H2 D Ignore carrier detect ----^ Carrier off ------------^ Go off-hook w/o closing auxiliary relay contacts---^ Commands to receive 1270 Hz mark, 1070 Hz space: AT S10=255 C0 H2 A Commands to transmit 2225 Hz mark, 2025 Hz space: AT S10=255 A Commands to transmit 1270 Hz mark, 1070 Hz space: AT S10=255 D Command to stop transmitting: AT H --- TBBS v2.0 * Origin: Atlanta Connection - Voice of Atlanta (404-929-0800) (133/205)