[SMCARA] RTTY Macros and Operating basics

Sat Jan 3 12:23:25 EST 2015

Not sure of LSB on RTTY. I am using DM-780 is configured on my dx3000
as Data and USB for my 20 or so RTTY contacts and also same settings
for any PSK I use. I ave not switched anything else in DM-780. I will
play with it later on LSB and check the results. 73's Bill

On Sat, Jan 3, 2015 at 11:35 AM, Tom Shelton <gl1800winger at verizon.net> wrote:
> Starting at 1:00PM (EST) today brings us the ARRL RTTY Roundup.  This post
> isn't about the contest, but about RTTY in general.  If you are interested
> in doing the contest, information and rules can be found on the ARRL
> web-site at: http://www.arrl.org/rtty-roundup
>
>
>
> An RTTY transmitter sends out a continuous carrier that shifts frequency
> back and forth between two distinct frequencies. There is no amplitude
> modulation, only a pure carrier similar to CW with the addition of a
> frequency shift. The lower RF frequency is known as the SPACE frequency and
> the upper RF frequency is known as the MARK frequency. The difference
> between the two is known as the SHIFT. For amateur radio, the SHIFT has been
> standardized at 170 Hz. This allows sharp 250-500 Hz audio filtering.
>
>
>
> The recommended audio frequencies are 2125 Hz for the MARK audio frequency
> and 2295 Hz for the SPACE audio frequency. Note that the SPACE audio
> frequency is higher than the MARK audio frequency - just the opposite of the
> RF frequency of the actual transmission. This happens because amateur radio
> RTTY uses lower sideband (LSB) transmission. If you happen to forget and set
> your transmitter to USB instead of LSB, two things will happen. Because your
> MARK and SPACE are now reversed in your receiver, any RTTY signals you hear
> will not print correctly. All you will see is random characters that make no
> sense at all. The other thing is that transmissions will also be reversed.
> Modern RTTY software has simple controls to reverse received signals. Note
> that USB is used in some parts of the world, esp. in Europe.
>
>
>
> 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 a computer does.
> Unlike a computer, which uses one byte (eight bits) for each character, the
> Baudot code uses only five bit, 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 latin alphabet plus
> ten numbers, plus some punctuation, 32 different characters is not enough,
> even if you only use capital letters, as does the Baudot code. Rather than
> using more bits, Mr. Baudot came up with an other 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 characters. He
> then had six possible 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. When sending one of the basic 32 characters, nothing special happens.
> But when a number or punctuation is to be sent, the Figures Shift  character
> is sent first (it's a non-printing character). Whatever follows will still
> be one of the basic 32 characters (bit patterns), 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. Characters may get corrupted due to interference from
> lightning, static, man-made noise, channel fading, etc., causing inadvertent
> letter-figure shifts.
>
>
>
> Given this - when setting up your macros, try to minimize the shift between
> numbers and letters.  For example, when sending a signal report, send it as
> 599 instead of 5NN.  As a side note - you may also see INN as a signal
> report or TOO (early TTY terminals didn't have numbers and you shifted the T
> & O keys to give you the 5 & 9 - operators using these tools didn't bother
> with the shift and just sent TOO to increase their typing speed).
>
>
>
> If you are using Ham Radio Deluxe (DM-780), which originated in Europe, the
> default set-up for RTTY is designed for using USB in RTTY mode.  In the rest
> of the world, LSB is the standard (regardless of band) - In order for your
> log to match the receiving station, you'll want to use LSB and set DM-780 to
> reverse the mark and space (there's a button for that on your screen).
>
>
>
> For contesting, keep your macros short.  When calling another station, just
> send your call.  For your report, send <his call> 599 MD <your call>.  Have
> a couple of macros set-up to ask for repeats (in the RTTY-RU, you might need
> to ask for a repeat on a QTH or serial number (for DX).  Also have a macro
> set-up to repeat your QTH (mine reads MD MD MD).
>
>
>
> Generally running a frequency will give you the best rates, but it's
> difficult and if you get a pile-up, it can be very frustrating.  In this
> particular contest, search and pounce can easily keep your Q-Rate at 40-60
> QSOs per hour and is much less infuriating.
>
>
>
> A couple of good resources for RTTY and RTTY Contesting are:
>
> http://www.nonstopsystems.com/radio/frank_radio_rtty.htm (almost all of the
> above was stolen from this page)
>
> http://www.rttycontesting.com/
>
>
>
> Hope to hear you on the air today and tomorrow.
>
>
>
> 73
>
>
>
> Tom Shelton, ND3N
>
> Ham Radio, Motorcycling, and a Loving Wife who lets me play with both
>
> What more could a man need
>
>
>
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