First Time RTTY QSO ever

Pat WW9R

I have always wanted to try RTTY but never having seen it operated, I was not sure how to proceed.  As a avid contester, I wanted to be able to participate in the RTTY contests.  This was one of the reasons I purchased the Flex 6300.  I knew it would be a great cw contest radio and I hoped it would help me get into RTTY contests as well.

Once version 1.5 of the SDR software came out, I knew I had to try the CQWW RTTY contest.  The presentations by K9WX at the W9DXCC and at the SMC Fest gave me the background on what to expect while operating RTTY.  Now I just needed to figure out how to set up my radio.  Based on the posts in the Community it was very simple to set up.  After hearing all the hoops people go through with other radios (non-Flex SDRs), I couldn't believe that after a couple of mouse clicks, I was operating RTTY.  DAX Rocks!

To be honest, It took me a while to get into the flow of the contest exchange.  So I used this past weekend's CQWW RTTY contest as a learning experience.  While I was having fun operating, I even figured out that if I expanded out the band slice, I could see the twin peaks of the two RTTY tones for each station.  This helped speed up the final tuning process in 2Tone.  The use of the waterfall made finding a run frequency very easy.  It seemed like I had stumbled upon a secret weapon for running in contests.  In contesting, it is all about finding that next dB of advantage.  The speed at which I was able to S&P or find a run frequency was amazing.  I can't believe what an advantage it is to see the band graphically.  I entered the contest "assisted".  After using the features of the 6300, I didn't use the spotting network at all.  

My Setup:
HP, Assisted, All band
Flex 6300, ver 1.5 SDR
100 W & 600 W  ( I entered as HP so I could experiment between the two, to see the difference in QSO rates)
Ameritron AL-811H
Gap Titan vertical (10, 15, and 20 meters)
Vap Voyager vertical (40 and 80 meters)

N1MM+
2Tone

My score after 12 hours of operating over the weekend:


Now that I understand how to use my 6300 in a RTTY contest, I expect my rates to improve.  

Thank you for opening up a whole new area of contesting for me!

Pat WW9R

Walt

You could not have put it any better why RTTY filters were considered by many RTTY people to be a real weak link until ver. 1.5.  I am glad Flex got this work done.  Next, FSK to help everyone have the cleanest possible signal on the band.

Glad you enjoyed the contest, the more competition, the better.

Cheers

Ken - NM9P

Fun isn't it?  Nice score for a first time RTTY contest dabble.

I dabbled in it a couple of years ago, but I don't think I even submitted a score.  It wasn't pretty.  But this year I made a major effort and was very impressed at the ease in tuning, finding contacts, filtering out interference, etc.  I may try with RTTY Skimmer next time.  I have used CW Skimmer, but haven't done enough RTTY to justify the purchase of the program until now.

Good luck!

K9DUR

Pat,

Welcome aboard!  I have been enjoying RTTY & CW contesting with my Flex radios for several years. 

Go SMC!

73, Ray, K9DUR

k0eoo

I may as well throw my log on the fire, this was my first time on RTTY too....  What a hoot, wish i had been using N1MM+, DX4WIN would change modes when I clicked on a spot making things slow....  Ended up just doing Tune-N-Pounce...

My main goal was to work as many new countries on RTTY as I could.  I started at '0' and ended at 82 out of 182 Q's from 80m to 15m in 8 hrs of operation..... 

1. Flex6500 V1.5 & DDUtil controlling SteppIR, Ant switching, rotor & Amp...
2. DX4WIN logging program
3. FLdigi
4. 100/500W (4 hr at 100w and 4 hr at 500w) W/KPA-500
5. 3el SteppIR @ 80'
6. 2el 40m monobander @ 90'
7. 80m Coaxial-resonant match broad band inverted V dipole @ 80'

In many cases I was able to get within 100Hz of a strong 59+ signal and still copy a 55 signal, very  impressive performance....  Lots of fun, thanks FRS for adding the RTTY mode!!

Dennis, k0eoo

Ken - NM9P

Yes, the filtering is superb!  I used 300 Hz filters for most of the contest with N1MM+ and MMTTY.  The only time I couldn't get close to another strong station was when that strong station was wider than normal.  I was a few that were oblivious to the width of their own signal. (Or WERE they?  Sometimes I have observed a few contesters go "wide" on purpose in order to clear a "hole" around them - that's cheating.)

I changed MMTTY receiver decoders often, experimentation being the key.  Depending upon band and conditions, changing between IIR to FIR often made a difference.  I didn't use PLL much.  This will be a subject of more experimentation.

I was often able to decode effectively when equally strong stations were overlapping each other, spaced halfway between each other - one's mark between the other station's two tones.

Ken - NM9P

km9r.mike

I think one would be hard pressed to have a cleaner rtty signal than flex SS + fldigi. The rtty sig produced is an order of magnitude cleaner than afsk generated by MMTTY and while I have zero fsk experience, I can see other rtty signals on my flex waterfall and few compare with the clean sig that I see w/ my flex SS and fldigi and I am using a stock soundcard in my computer. If I understood better how audio tones are commanded by the fldigi software and if a high end soundcard would produce even more discreet and higher quality tones then I would invest in such a soundcard. However, since the afsk rtty signals generated by the stock soundcard are already at the top end of quality, I do not know if a high end soundcard would be worth the cost. A lot of people do claim that they hear a difference in listening to digital music so at a minimum it might be worth the cost just for that.

Tim - W4TME

The additional noise and degradation of SNR due to the analog-to-digital-to-analog conversion that would be inured using an external sound card negates any possible signal improvement benefit.  The ADC in the FLEX-6000 is exceptional and keeping the audio signals entirely in the digital domain is one reason the 6000 makes an exceptional digital mode radio.

km9r.mike

I may have a gross conceptual error here. I thought fldigi commanded my pc's soundcard to generate audio tones(analog) that are sent to my flex 6300 via the virtual dax cables (dax converts the pc soundcard analog output to digital ) .So no matter how good of a pc soundcard I bought, it would be limited by the A to D conversion that dax is utilizing w/in my pc ? Also for additional better understanding, if the previous is correct, then with headphones plugged into my flex SS, I can hear dax transmitted signals via the monitor feature because of a D to A conversion within my flex ?

Or instead of fldigi commanding my pc's soundcard to generate audio tones to be transmitted by my flex or any other rig, dax utilizes the digital equivalent generated by fldigi that is the input to my pc soundcard ? 

Sorry but I have limited understanding of software and the workings of pc and how flex capitalizes the technology.

Tim - W4TME

OK.  Here is the deal with every digital mode program.  Sound cards do not generate tones. The software (Fldigi) generates and decodes the "tones" in DSP software.  On TX, it  sends the digitized (binary) tones to the sound card to convert then from a digital signal to an analog signal.  On receive, the reverse is true; analog audio from a traditional radio is fed into the sound card to convert an analog signal to digital so that it can be used by Fldigi.  The only purpose of a hardware sound card is to do the analog-to-digital conversion (ADC) and digital-to-analog conversion (DAC)

Fldigi can only send and receive audio in a digital format to a Windows sound device (sound card).

With the FLEX-6000, there is no need to do the analog-to-digital and digital-to-analog conversions because the audio in the radio is already digital.  However, since Fldigi is designed to work with traditional radio that use an analog interface, we must emulate a sound card interface and we do that using DAX.

Your PC sound card is never used in this configuration.

And any analog signal you hear coming out of the FLEX-6000 is generated by its internal DAC.

km9r.mike

So fldigi communicates directly to flex via dax which emulates the traditional pc soundcard hence direct D to D communication hence the very discreet and precise signal I see being displayed by flex in the tx waterfall and sharp peaks in the panadapter when using fldigi. I did not understand the function of dax fully. I thought it emulated virtual cables only. A virtual means to utilize my traditional pc soundcard output but that is not the case at all. Thanks for helping me to understand better and saving me money : ) and grief from a future letdown : )

Tim - W4TME

So fldigi communicates directly to flex via dax which emulates the traditional pc soundcard hence direct D to D communication hence the very discreet and precise signal I see being displayed by flex in the tx waterfall and sharp peaks in the panadapter when using fldigi. 

That is exactly correct.  And it is one reason the FLEX-6000 (and the older FLEX Series SDRs) are the best for digital mode operation.

km9r.mike

It shows : )

Burt Fisher

I have use RTTY with Fldigi, how will RTTY be better if I upgrade to 1.5? It seemed fine as it was.

Ken - NM9P

Burt,

On my 6500, the new RTTY mode makes it much easier to set up, without the need to use the work-around setting the RIT/XIT etc. If you have the filter set at Narrow (300 Hz), and zoom in the panadapter, there are marks for both the Mark & Space tones that are so accurate that you don't need to use any other tuning indicator. (If you have the Mark Frequency, shift, and sweet spot frequencies set correctly in both SSDR and your RTTY program.)

This weekend I was able to click-tune on the Mark peak of stations and it was dead-on.  The same was true for clicking on spots from N1MM+ during the contest.  If the spots were entered correctly, I was dead on frequency.

If I set the TX Filters to 300 to 600 Hz wide (and saved them as a TX Profile fr future use) then if I used XIT, the transmit stripe would also indicate exactly where my "twin peaks" were going to be.

All in all, the RTTY mode was very nicely implemented and very worth the time to upgrade.  

I found the noise blanker effective on many of my noise sources.  And I experienced a few problems when  had it turned up too high in certain situations.  But that is the case with any noise blanker -- too high a setting can cause problems, and no single blanker will solve ALL sources of noise.  

Ken - NM9P

Burt Fisher

With Fldigi I never had a problem getting right on the station in less than a second. I needed no work around. I have no idea what this sweet spot is nor did I need to do a dance of XIT, filters or whatever, just click and go.

k3Tim

and the AFSK is wave shaped by the RTTY app for cleaner transmit signal.  FlDigi has this capability.

Ken - NM9P

It depends upon which tuning style you use with FLDigi .

Method 1) Some operators park the rig on a single frequency with a wide filter and tune stations by clicking on the FLDigi panadapter.  The rig never changes frequency unless you want to tune stations outside the bandwidth of the wide filter.  This is simple, and allows things like RTTY-Skimmer to be used as well as other multiple tuning windows similar to PSK31 applications.  The disadvantage, in a crowded band, is that you don't get to use SSDR's excellent narrow filter.

Method 2) Another approach is to set the tune & Transmit frequency in FLDigi to a center frequency (set as a sweet-spot) which is defaulted at 1500 in FLDigi.  This sets the decode window to default to the center of the standard filter in SSDR, allowing easy use of the brickwall filter in SSDR.  Tuning is then accomplished by tuning the rig itself and leaving the FLDigi pan display on the default frequency.  

In previous versions of SSDR, the problem with this approach is that it required careful adjustment of RIT/XIT frequencies, FLDigi sweet spot parameter, receive filter high & Low settings, and other parameters in order to get the filter centered correctly to allow click tunng on the SSDR panadapter.  When using XITto work splits it was also a little inconvenient because the receive and transmit frequencies were far removed from the rig's "Carrier frequency" when tuning.  This was especially unhandy when the display was zoomed in closely.  It didn't take far before the XIT transmit frequency **** was off the screen.  also, when click-tuning or spot-clicking for quick frequency changes, the frequency reported t the logger or spotting network was not accurate, sometimes off by 2025 Hz if using the standard tones.  (This could be fixed using the RIT/XIT workaround, but was a pain.)

The new RTTY mode allows all of this to be simplified.  There is a parameter under DSP in RTTY mode that allows setting the Mark frequency and shift.  This then centers the RTTY signal in the center of the filter passband, which includes mark and space indicators that serve as extremely accurate tuning indicators.  The frequency on the display, and reported to loggers and spotting networks is reported correctly as the actual RTTY Mark frequency.  Using a 300 Hz filter is simple, and there is not display offset to account for.

If one sets up a TX Profile with TX filters centered on the RTTY audio frequency and with the proper bandwidth, then the XIT transmit frequency **** in SSDR will also accurately reflect the actual transmit frequency location on the SSDR panadapter, including the RTTY Mark & Space indicators.  

When setting up FLdigi, MMTTY or other applications, it is only necessary to set the RX & TX tone frequencies to match the Mark frequency and shift that is also set in SSDR's RTTY mode.  in FLdigi, setting the Sweet Spot (default position on Fldigi's own panadapter) will allow simple tuning using only the SSDR controls.  Fldigi and other rtty programs only go along for the ride.

I hope this helps explain the difference that the new RTTY mode makes.  It is helpful for those who wish to use the Method 2 approach to RTTY.  Those who wish to use Method 1 should probably still use SSDR's DIGIL mode rather than RTTY mode.
  
It actually took longer to type this than it did to set things up!  

Ken - NM9P

Burt Fisher

It would seem a lot easier and with no loss in anything to just use Fldigi. As I have a 6300 why would I want to upgrade? Just for the noise limiting that seems to work if you do two turns to the right, jump twice and sing the National Anthem? Do other rigs require a balancing act? I am eager to be corrected if I am wrong in my assessment. 

Tim - W4TME

To each his own.  Whatever works best for you, do it.

Burt Fisher

Even after what I said above the best reason to own a Flex is it is totally unique in the support we all get. Name me ANY company that comes close