[South Florida DX Association] RTTY Gazette - April 2005

[Bill Marx]

 RTTY Gazette - April 2005

Greetings, everyone and welcome to this issue of the RTTY Gazette.   A few
subscribers volunteered some interesting things for this issue.  This
promises to be our largest issue yet, so let's get started.

I am writing this issue as the FT5XO DXpedition to Kerguelen Island is
closing up shop after providing contacts to thousands of deserving amateurs.
They were active on SSB, CW, and RTTY.  If you were one of the lucky ones to
bag them on RTTY, I envy your accomplishment.  The propagation gods were not
in our favor here in Michigan as I had only one brief 15 minute opening on
30 meters. I heard plenty of stations in the pileups but nary a whisper from
FT5XO.  Nope, no RTTY contact for station WI8W.  The usual lids were
apparent with many calling on their transmit frequency. Apparently they do
not know the meaning of.UP UP.

All was not lost though as on Monday evening past I did manage to bag them
using our most primitive digital mode.CW.  Well at least I will get a card
and can say that I did get to work em!  I wonder if they are producing a
video of the effort?

How about you?  Got any stories to tell?  How did you bag em?

So now the sun has crossed the Equator on it's yearly travels into the
Northern Hemisphere which will bring high static levels to the low bands and
maybe some enhanced propagation to the high ones.  There are a few more
great DXpeditions coming up that we can all chase down for that new one in
the log.

It is also almost antenna season. I have some new things I want to put up
and some things that need a bit of fixing. How about you?  What are you
planning for the coming season?

Beginning in this issue, and continuing in a few future issues, we will be
presenting a overview of  linked digital modes written and provided by
Jeremy N1ZZZ.  Here is the first part, reprinted with permission of Jeremy.

Ham Radio Linked Modes:
By Jeremy Allen N1ZZZ

This is the first of a series of articles that I hope will shed some light
on the various linked modes used in radio today, especially in the HF bands.
Linked, or burst modes, is the family of protocols that link one or more
stations for the purpose of transmitting error-free data, usually at
moderate to fast rates.

Linked modes vary, however they have many common requirements.  In every
linked mode, the T/R switching speed and timing are critical.  Most modern
transceivers are quick enough to meet these requirements, but some old "boat
anchors" are not the best choice for linked modes.  Also, most soundcard
applications are not suitable for linked modes because of the timing delays
that are inherent in many computer operating systems.  The exception to the
timing rule is packet, which has a looser timing sequence.  Soundcard packet
is the only viable linked mode currently available.  Also important is
frequency stability.  This is very important for some of the fastest modes
such as Clover and PacTor 2/3.  In any case, if the frequency of the signal
drifts too much, then the link will be lost.

Linked modes are found as part of MCP's (multi-mode control processors).
There are a wide variety of controllers on the new and used market.  Various
modes are available on the different models, however almost every MCP will
have AMTOR, and PacTor linked mode, as well as older modes such as Baudot
RTTY.  A number of manufacturers market MCP's with proprietary modes, so
choosing a MCP is a combination of performance as well as desired features
and modes.

As a result of the surge in the use of the Soundcards, MCP's is a buyers
market.  Good MCP's can be obtained for under $100 dollars now, so now many
of these linked modes are available even to budget-conscious hams.

The major strength of all linked modes is error correction.  Although it
might take awhile to pass the message, operators can be certain that
whatever is on their screen was what the other station sent.  While modes
like PSK31 and MFSK16 are very robust, and incorporate FEC, it is not
uncommon at all to get junk characters on the screen.  This is not the case
with the linked modes.  In addition, with the exception of AMTOR, linked
modes can transmit binary files at fairly fast speeds, enabling users to
transfer more than just text.  Graphics files and even short programs can
easily be exchanged with little worry about corrupt or missing data.  So
despite the increasing popularity of the soundcard modes among digital
operators, the burst modes continue to hold a place in the ranks of amateur
radio.


AMTOR: The First Amateur Linked Mode

Before AMTOR hit the amateur airwaves around 1983, the only method to move
text over the amateur airwaves was RTTY.  The problem with RTTY was that
there was no error correction at all.  If any of the bits were corrupted
enroute, the text was not displayed correctly.  In order to introduce some
error correction into digital communications, a mode called SITOR was
developed for commercial use.  This mode was adapted for use in amateur
radio by G3PLX, and called AMTOR, which means Amateur Teleprinting Over
Radio. Amtor uses the 5-bit Baudot code, the same as RTTY, which allows for
operators to pass capital letters, number, and a limited number of symbols.
Lower case letters cannot to be transmitted because there are not enough bit
combinations in the Baudot code to encode them.  This problem would have to
wait for more advanced modes to be solved.
AMTOR comes in two flavors, or Modes.  First is Mode-A, or ARQ (automatic
Repeat Request), which is when two stations are linked and exchanging date.
Mode-B uses FEC (forward error correction) which basically repeats every bit
twice, with the hope that one of the two will get through to the other
station.  Mode-B is used for, broadcasting, round table discussions, and
calling CQ.  This signal sounds somewhat like a standard RTTY signal.  The
best place today to listen for a Mode-B signal is to listen to the W1AW
bulletin broadcast.
Mode-A is the most well known AMTOR mode.  The signal sounds like a series
of chirps as the two stations exchange data.  The link is established when
one station uses a 4-letter SelCal code to call the other station.  Selcals
are most likely a contraction of the station's call sign.  For example, my
selcal is NZZZ, omitting the 1 of my call sign.  Usually the terminal
software will automatically transform the station's call sign into a selcal.
The software will also display the set selcal when calling CQ in mode-B to
eliminate confusion, and allow the other station to initiate the link.
When two stations are linked, the one sending data is called the master, or
ISS (Information sending station) station; whereas the receiving station is
the slave, or IRS (information receiving station).  The ISS will send data
in 3 character blocks.  If the whole data block is received without error,
the IRS will send an ACK (acknowledge) signal, and the ISS will send the
next block of data.  If the data is corrupted en-route, the IRS will send a
NAK (not-acknowledge) code, and the ISS will resend the block until it is
received correctly.  The ISS will also resent the data if no signal or a
corrupted ACK/NAK signal is not received from IRS.  When the ISS is through
sending data, the operator sends a specific command and the ISS becomes the
IRS while the IRS becomes ISS.
Under good conditions, an AMTOR link will pass data at about 100 baud.  This
will exchange text as fast, or faster than most people can type.  This mode,
because of the Baudot code, cannot be used to exchange data files however,
but is good for keyboard QSO's.  If the conditions are not very good, the
throughput will be reduced dramatically as the number of NAK signals
increases.  If the conditions really take a dive, the link will fail as the
number of repeats exceeds a preset number.  At this point MCP, will inform
the operator of the link failure and go back to a standby mode.
So how do we get on AMTOR?  The best way to get on AMTOR is through a
Multimode Control Processor (MCP).  Most any MCP available today will
operate both Mode-A and B.  Soundcards, the new rage among digital
operators, can be used to work Mode-B but because of timing issues on most
operating systems, Mode-A is not feasible.  The real issue with AMTOR is
that there are better, more robust modes, such as PacTor out there, so the
use of AMTOR has reduced to a trickle.  There are some AMTOR signals out
there, mostly around 14.080 LSB on 20 meters, but a sked would probably be
the best way to get some AMTOR QSO's in the log.
In the next installment, we will look at the "improved" version of AMTOR,
PacTor.


Thanks Jeremy.part 2 next month.

Next we have a short article from Jeff N3YEA.  Not necessarily about digital
communications but it just might get you to thinking about how you got
started in this wonderful hobby.  I know I am thinking about it right now.
Here is Jeff's article.

I was always interested in radio , as a young child I would do odd jobs to
get enough money to buy the small short-wave receiver kits. String a long
wire across the backyard , which seemed high to me, but my Dad would always
run into them when he was mowing the yard.

I would tune around the SW bands for hours, listening to all the different
languages, and those strange signals. Then someone gave me a Zenith
Trans-Oceanic , which really opened my world up. I would log the different
stations, and spend hours searching for new stations and those strange
signals. I received an Amateur License Study Guide, but being 10 to 12 years
old - I understood very little in it, but I think I memorized most of it,
just by reading it so often. I never could find a Elmer, back then you
really didn't have an easy way of finding one, if you didn't know someone,
or knew someone who knew someone.

It was also when you had to travel to a major city to take the tests - which
I never felt confident enough in my knowledge to ask my Dad to take a day
off of work to drive a couple of hours to take the test. Heck - I didn't
have any money for rigs anyhow. I remember dreaming over the newest Heathkit
catalogs I would get. But then - I got into junior and senior high schools
and discovered sports, girls and cars and the hobby was forgotten. Upon
graduating from high school, I enlisted in the U.S. Army - where I wanted to
be a truck driver, but their testing revealed that I had an aptitude for
something else, in the "Army Security Agency" . But they couldn't tell me
exactly what it was , because it was classified.

So - off to Security Agency school I went - and lo and behold - the first
part was learning CW , so for 3 months, 6 hours per day, I learned CW , and
when you spend that much time learning it - you learn in very well. The next
few months were spent learning how to receive ( intercept ) RTTY signals.
You can imagine my glee, getting my hands on all those "state of the art"
R-390's , and the teletype machines, along with all the demodulators. And
the antenna arrays !!! -- simply amazing to me..  many times, I would go in
during my off hours, find an un-used R-390 and tune around , listening to
even more stranger signals...

When my service time came to an end, I got back into the mainstream of life,
and radio bug again took a back seat, to getting married, buying the first
house, raising a daughter and so on.. When my grandfather passed away, one
of the things I was given, was a radio he had, that used to listen to the
ballgames on. It also had a short-wave band on it, so there I was again,
listening to the signals -- and this time - I could identify some of the
them! Well, the bug was back , and I bought another up to date study guide.
Now I had the internet to look up information - Wow - you could go somewhere
local and take the test! so after a couple of months of studying, with my
wife and daughter reading the practice questions to me at the dinner table,
and getting back up to par at CW. I was surprised, that after nothing to do
with CW for 21 years - it came back fairly easily. I contacted a local club
and registered for their next test session. That October evening, I passed
the 13 WPM code test, the Novice, Technician, and Technician plus exams. The
first rig was a used Kenwood TS-520s and a Hustler 5 band vertical antenna
and a straight key.. So many bands, so many people talking, so many on CW
and there were those RTTY signals.   After listening for a couple of weeks
waiting on my call to be assigned and to get the feel of how things worked -
it was time. Armed with my new callsign, clammy palms, and shaking hands -- 
I tuned around the 80 meter CW band.. and there he was - KB9NUG , calling CQ
..   I tapped out my call sign twice .. and HE ANSWERED ME !

It's funny how you remember your first contact -- at least I do.. When I
told him he was my very first contact, and that I was very nervous, he kept
offering to QRS, and I kept telling him the speed was fine - no problem at
all. It turned out he was visiting his father in Chicago, using his fathers
rig. That is how they kept in touch, His call was WB9BXX, and when I got his
qsl card - he had written on it, something that I think I'll always
remember --  " Thanks for making me your first contact."

But I couldn't stay away from the digital portions of the bands -- my first
TNC was a MFJ-1278. Since then, I have learned so much, have met so many
people, and have
upgraded my equipment and license. I'm now running a Yaesu FT1000MP Mark V,
and a Rigblaster and am just about exclusively digital. I still have that
520 S and 1278 sitting on my desk, I should sell it - but there are so many
memories attached to it -
I hand out points in most every RTTY contest , and very rarely turn in a
score sheet - I send in my logs for check logs.

It's funny - during contests, at times, I'll listen to those RTTY tones, and
I'll be taken back to my Army days, turning the big knob on the R-390,
getting the "crossed banana's " just right, and hearing the teletype machine
behind me, hammering out the letters and numbers. Then further back, to a
little black plastic short-wave radio kit I built.

73 , de
Jeff - N3YEA

Thanks Jeff,  I may just put my story in here in a future issue.


Have you got a story to tell?  I am sure there are others who would like to
read about it.


As you are probably aware this publication is distributed world wide not
only through email but also on PACKET, AMTOR, PACTOR and other networks.  If
you are responsible for placing this publication on any outside networks
please contact me.  I would like to try to get a feel for just how large an
audience this publication reaches.  I also would like your input on the
ability of those networks to handle graphic images and PDF files.

I would also like input from you, the reader, on the subject of including
images in the RTTY Gazette.  There is a lot we can do with this publication.
Let's explore the possibilities.

That about does it for the news and features.on to the Announcements.

***************************************************

ANNOUNCED DXPEDITIONS  -  APRIL 2005

Mar30 - Apr4 Cyprus 5B4
By LY1DF as 5B4/LY1DF; 80m + WARC; CW; QRV mainly afternoon hours

Apr1 - Apr9 Cayman Islands ZF2UJK
By K4UJ fm Grand Cayman Is; 80 40 20 17 12 10m; CW SSB fm north side of
island

Apr1 - Apr15 Bolivia CP6D
By DF9GR as CP6/DF9GR fm southern Bolivia; 80-10m; mainly CW RTTY PSK; QSL
OK via DARC Buro

Apr3 - May05 Dominican Republic HI8IK
By IW2OAZ fm Sto Domingo and Bayahibe; QSL OK via Buro or direct

Apr4 -  Apr12 South Cook Islands ZK1APX
By AI5P; 40-10m; CW

Apr6 - Apr20 Botswana A25
By DL7CM DM2AYO as A25/homecall (perhaps A25CM); 160-6m; CW SSB RTTY PSK

Apr7 - Apr11 Macao XX9
By JA0SC; 20 15 10m; SSTV RTTY

Apr15 - Apr29   Bahamas C6AWF
By G4WFQ fm Treasure Cay, Abaco Is (NA-080); 80-10m; CW, RTTY, some SSB; QSL
via G3SWH or LotW

Apr18 - Apr25   Ghana 9G5
By DL7DF; 160-10m; CW, some SSTV; yagi + dipole; 700w

Apr19 - Apr29   Kyrghyzstan EX
By ES1FB as EX/ES1FB; holiday style operation; QSL: Jaak Meier, Box 2907,
13102, Tallinn, Estonia

Apr19 -  May17  Kyrghyzstan  EX
By ES1RA as EX/ES1RA; holiday style operation; QSL: Oleg Mir, Box 806,
11702, Tallinn, Estonia

Apr20 - May8   Mongolia JT1Y
By I0SNY; Apr 25-26 as JT2Y from Choybalsan, Khosbayar; QSL OK via Buro or
direct Apr22 - Apr25   Liechtenstein    HB0
By IZ1DSH IK1WEG IZ1GDB as HB0/homecall; 80-10m; CW SSB; QSL OK via ARI Buro
or direct

Apr22 - Apr25   Luxembourg   LX
By ON4BAG ON4LO ON6QX ON6UM as LX/homecall; 160-10m; SSB CW Digital; QSL OK
via Buro or direct

Apr22 - Apr26   Liechtenstein   HB0
By IZ1DSH IZ1GDB as HB0/homecall fm Gaflei Malbun; 80 40 20 30m; CW SSB; QSL
OK via Buro or direct

Apr23 - May1   Egypt    SU8IOTA
By SU1HM SU1SK SU2TA SU1SA fm Disuqi Is (AF-NEW) in the Nile Delta and Sinai
Region Group: QSL: Said Kamel, PO Box 190, New Ramsis Center, Cairo 11794,
Egypt

******************************************************

UPCOMING CONTESTS - APRIL 2005


EA RTTY Contest 1600Z, Apr 2 to 1600Z, Apr 3
RSGB 80m Club Championship, CW 2000Z-2130Z, Apr 4
ARS Spartan Sprint         0200Z-0400Z, Apr 5
YLRL DX-YL to NA-YL Contest, CW 1400Z, Apr 6 to 0200Z, Apr 8
JIDX CW Contest 0700Z, Apr 9 to 1300Z, Apr 10
ARCI Spring QSO Party 1200Z, Apr 9 to 2400Z, Apr 10
TARA Skirmish Digital Prefix Contest 0000Z-2400Z, Apr 16
EU Spring Sprint, CW         1500Z-1859Z, Apr 16
NAQCC Weeknight 40/80-Meter Sprint 0030Z-0430Z, Apr 20
RSGB 80m Club Championship, Data 2000Z-2130Z, Apr 21
SP DX RTTY Contest         1200Z, Apr 23 to 1200Z, Apr 24
EUCW/FISTS QRS Party 0001Z, Apr 24 to 2359Z, Apr 30


That about does it for this issue.  Have fun and Good DX

73

Thom WI8W