RTTY

[SARGE]

What exactly is RTTY and what is it used for . Thanks for the help.

 

[Sonwatcher]

It is radioteletype, a digital mode. In Amateur use it is a popular mode on 20 meters. In the military it is referred to as RATT. Below is a tutorial of how it works-

RTTY uses the Baudot code, invented before radio even existed, and still widely used throughout the world. The Baudot code uses data bits to represent letters, numbers and punctuation, much like your computer does. Unlike your computer, which uses eight bits for each character, the Baudot code uses only five, plus a start bit and stop bit. Using fewer bits is good because it speeds up transmission and reduces the chance of errors, but there is a complication. Five data bits can only represent 32 different characters. Since there are 26 letters in the English alphabet plus ten numbers, plus some punctuation, 32 different characters is not enough, even if you only use capital letters, which Baudot does.

Mr. Baudot could have chosen to use six data bits or even more, but he found a better solution. He reasoned that most of what would be sent would be letters rather than numbers or punctuation, so he assigned all the letters to the basic 32. He then had six characters left over and he did a very clever thing with two of them. He made one of them a FIGURES SHIFT and another a LETTERS SHIFT. The way it works is this: When sending one of the basic 32 characters, nothing special happens. But when a number or punctuation is to be sent, a FIGURES SHIFT character is sent first (it's a non-printing character - you won't see it on your screen).

Whatever follows will still be one of the basic 32 characters, but the receiver will interpret it differently. For example the letter Q uses the same five data bits as the number 1, but when the receiver gets a FIGURES SHIFT first, it prints the next character as a 1, not a Q. This continues until a LETTERS SHIFT character is received, at which time the receiver goes back to "normal" printing. All of this shifting is done by the system - there is no key marked LETTERS SHIFT or FIGURES SHIFT. It's all automatic and you will scarcely notice it happening.
In fact, the only reason to mention it at all is because we are using radio instead of wires, and radio is susceptible to interference from various sources such as lightning static, man-made noise, etc.

If a burst of static should happen to wipe out a LETTERS SHIFT or FIGURES SHIFT character, the characters following will not print correctly until another LETTERS SHIFT or FIGURES SHIFT is received. For example, suppose you are sending a signal report of 599, but a burst of static wipes out the FIGURES SHIFT character. Instead of printing 599, the other fellow's computer will print TOO. TOO is exactly the same as 599, without the FIGURES SHIFT. We all got used to interpolating "shift" transmitted reports and serial numbers in the early days!

More here- http://www.southgatearc.org/data/rtty/

I have listened to it and it seems to not carry as much conversation as other modes do. You can download software to translate or send it.

 

[SARGE]

Sonwatcher

Thanks for the help.Thats some good info.

 

[K8PG]

AMATEUR RTTY -MARK and Space -STANDARDS

Each character in the Baudot RTTY code is composed of 5 bits.In amateur RTTY communications a "1" bit is usually represented by a 2125Hz. tone and is known as a mark.A "0" bit is represented by a 2295Hz tone called a space.There is also a pulse at tha begnning of a bit string and a stop pulse at the end.The data is commonly sent at a rate of 60 wpm,or 45 baud.A 170 Hz difference or shift between the mark and space frequencies.The Amateur Radio RTTY STANDARD is to use either a 170 or 200-Hz.shift. You can listen to it on 14.074-14.080 usb with the right software program, also 7.074-7.082
these are just a few of the active freq.segments that I use ,there are many more it is a very active mode and a lot of fun
DE-K8PG-Paul CW LIVES :usa

 

[SARGE]

Thanks K8PG for the info.Looks interesting

 

[N8YX]

Re: AMATEUR RTTY -MARK and Space -STANDARDS

You can listen to it on 14.074-14.080 usb with the right software program, also 7.074-7.082

Convention within the ARS is to use LSB for digital modes (RTTY, packet, etc). MARS and related military nets can and do use USB RTTY from time to time but most of these I've heard still use LSB.

You can find W1AW RTTY bulletins around the .095 area of each HF band.

Before 1996, many press services used HF RTTY as a news relay; they typically operated at 50 baud, 425hz shift. After '96 all the services switched to satellite and/or Internet links, eliminating the need for the HF feeds...which were subsequently taken off the air.

One can still find a few HF 'fixed' stations using RTTY; most run 850hz shift/57-75 baud and the transmissions are encrytped - usually by the method known as a one-time cipher.

A number of manufacturers have produced commercial, "dedicated" RTTY decoding gear...Drake, Yaesu, Infotech, Microlog, HAL and IRL to name several.

 

[SARGE]

N8YX

Thanks for the info.