[Mldxcc] ARRL RTTY Roundup

Thu Jan 3 17:30:56 EST 2013

Good stuff, Jeff.  I knew our expert would pop up!

Regarding the speaker, I should have clarified.  I do depend on the speaker and can generally tune by ear, using the XY pattern to fine tune.

Bob

________________________________
 From: Jeff Stai <wk6i.jeff at gmail.com>
To: Robert Hess <w1rh at yahoo.com> 
Cc: MLDXCC <mldxcc at contesting.com> 
Sent: Thursday, January 3, 2013 12:05 PM
Subject: Re: [Mldxcc] ARRL RTTY Roundup

hi Bob - Excellent information! I would just add a few things:

1. RTTY contesting is actually closer to a 50% duty cycle. This is still more than most amps have to deal with in a typical contest (consider that CW might be closer to 25-35%). You can dry run your amp before the contest into a dummy load (or, ahem, a clear frequency up the band...) Just set up a CQ buffer (something like RTTY RU W1RH W1RH CQ) and listen for the same amount of time as you transmit. Do this for a few minutes and see how hot things get and adjust accordingly.

2. The AA5AU site is definitely a highly recommended site. If you do what he says you should be successful. However, if you have a properly grounded station (and you should) you will probably be just fine with straight audio cables (i.e. no isolation transformers and such). Try it the easy way first.

3. Remember that the Baudot code used by RTTY uses a shift character to send numbers. What this means for you in a contest is that the shift character can get clobbered by QRM and you'll see letters in a place you were expecting numbers. The letters that are shifted to make numbers are the row of keys on your keyboard right below the row of numbers, so Q shifts to 1, W to 2, and so forth. So, when you see TOO-QWE from that DL station, you'll know it's really 599 123.

I only have one issue with one thing Bob said below: headphones. You should listen to the signal at a low volume level, and here's why:

- Your earliest indicator of when the other station starts and stops transmitting is by the audio. Your visual indicators are delayed by most of a second. That can be a lot when you have a nice rate going. You may also find like I do that you react quicker to the audio dropping away.

- If you have any sense of pitch at all, you will find you can tune in a signal faster by pitch than by using the visual indicator.

- There is a thing I call "the myth of perfect print" in RTTY. That's the notion that your computer will happily decode everything for you and present it to you in perfect order. In a contest it just doesn't happen that way. QRM and QSB will whack the other guy's signal just when they are sending that two character state code you need. After some practice, you will start to recognize the QRM and QSB (and flutter etc.) in the received signal and know when you are getting bad print even before it prints. And conversely, you'll know something is good print by the clarity of the signal and can judge the print accordingly. This ability can save you many fill requests over the course of a contest.

Have fun! - jeff wk6i

On Wed, Jan 2, 2013 at 6:13 PM, Robert Hess <w1rh at yahoo.com> wrote:

Hello MLDXCC'ers,
>
>This weekend is the ARRL RTTY Roundup.  It's a once a year contest where everyone works everyone on all bands.  This is a NCCC focus contest, so I encourage everyone to support the big club.  When you submit your score, it goes to NCCC (assuming you're a member).
>
>If you've never done a RTTY contest, it's easy chair, low pressure contesting for a beginner.  I find it a lot of fun and a low-fatigue way of contesting.  No headphones necessary and even no speaker necessary.
>
>I'm no expert on RTTY contesting (we do have experts in the Club, such as Jeff, WK6I) but I'll pass on a few random comments, should you want to get your feet wet this weekend:
>
>1 - Most RTTY contesters use Writelog, followed by N1MM as their logging software.  I'm not sure just what other logging programs easily accommodate RTTY.  With Writelog, you watch the screen, click on the call sign, then click on the exchange, both yours and the other guy's.  You can do the entire contest with just one hand on the mouse if you want to.
>
>2 - If you want to just play around, you can download MMTTY for free.
>
>http://www.aa5au.com/gettingstarted/rtty_downloadmmtty.htm
>
>
>I'm showing AA5AU's website for download information because this is the best site around for beginning RTTY'ers.  It walks you through everything.
>
>MMTTY is not a logging program.  It is built into logging programs like Writelog, but you can also use it as a stand-alone RTTY operating program.  It won't log the contest; it won't tell you that the guy you worked is a dupe, but it will let you work the station and then you manually log the contact.  It's an easy way to get started if you don't have a contest logging program that accommodates RTTY.
>
>3 - Many amps don't like the kind of duty cycle you have with RTTY, especially if you're running.  I run my amps at slightly below 1 KW, and I know W6SR will tell me I'm pushing an AL-1200 and Henry 3KD with that kind of power on RTTY.  I'd run a SB-220 at 500-750 watts and a SB-200 at 300-400 watts.
>
>4 - There are two ways to transmit a RTTY signal.  You can use AFSK of FSK.  
>
>AFSK depends on audio from your sound card, which is fed into your transmitter, via the microphone input or an auxiliary input.  
>
>FSK allows your computer to key the transmitter directly, via a simple interface between the computer and the FSK input on your transceiver (assuming it has an input for FSK).  
>
>I use FSK but the easiest way to get started is to use AFSK.  If you use AFSK, however, watch your levels and TURN OFF YOUR MICROPHONE PROCESSOR.
>
>5 - Receiving RTTY is really simple, if you just want to see what happens in a RTTY contest.  You can connect the speaker output, or preferably a line level output, directly into your computer sound card.  Load MMTTY, read AA5AU's tutorial, and watch the fun.  It's more fun, however, to actually be in the contest, transmitting and receiving RTTY.
>
>There's probably much more to add and other club members can feel free to jump in if you want.  And, since I'm no expert, feel free to correct anything I mentioned.
>
>The contest starts this Saturday, at 10 AM local time and ends at 4 PM local time on Sunday.  It's a 30 hour contest; entrants are limited to 24 hours of operation.  
>
>The exchange is state/province and signal report or serial number/signal report for DX.
>
>I plan on making at least 500 Q's this weekend.  If anyone wants to do some operating from my station during the contest, just let me know.  If you want to do a test prior to the contest, let me know.  If you have any questions, give me a ring, but remember that I am not the expert!
>
>Bob
>W1RH
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-- 
Jeff Stai ~ wk6i.jeff at gmail.com
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