Monday, April 27, 2009


I was asked to write a review on the 3K, so I started thinking about what I would need to include in my review. I'm a pretty simple guy. Give me a little rag chewing, and low band CW DX and a latte and I'm happy. I like to screw around with some home brew too. My latest is playing around with some stepper motors to see if I can build a big honkin remote antenna tuner. Mostly I just want to learn something about step motors and their control, plus I have all these old ATX power supplies from old computers laying around with nothing to do, so I figured I'd make them earn their keep.

I decided in order to do justice to the article I'd have to do some "Digital". Digital for me is like a root canal. I've dabbled in it, I even ran across some old friends on 20M that I had completely lost track of, but sitting around reading brag tapes just doesn't do it for me. Its too much like robot radio. I especially don't like PSK31. The dynamic range of that mode is so bad that if you run more than 30W you blow out everyone's receiver and mess up the throughput. It offends my high power bully nature. (I don't like QRP either, but I'll save the rant for another day) BUT I know there is a whole group out there who finds digital modes (and QRP) fascinating, so my hat's off to them and it's worth a few minutes of time to do some kind of rudimentary intro of digital. One good thing about digital is you can go make the latte or take a leak while the brag tape is running.

I haven't had anything digital hooked up since the Pegasus days around the time of 9-11. For that I used a Buckmaster interface and wires everywhere from the sound card. I can't remember which program I was using, but it took half a day of screwing around to get it running satisfactorily. I think the program was MIXW or something like that. I thought it was a really cool program. I think the other hot program of the day was Digipan or something, which I could never get to work.

I use the DXlab suite, and it has a fully featured digital program called Winwarbler, so I figured I would see how hard it was to set up. The answer is it is trivial. All the connections are done in software. It is merely a matter of configuration. There is no interface no wires and no sound card involved. It doesn't matter if I have windows dings or dongs or chimes turned off or on, because none of that is involved.

I use a program called VAC to route audio. VAC is essentially a virtual audio cable (hence the name VAC) I simply through the software route the output of a program to the input of another. To set up Winwarbler required 2 cables. One cable feeds PowerSDR's audio stream into Winwarbler and the other sends the transmit stream from Warbler to PowerSDR. It was easy as pie.

Next I had to set up PTT control. I use a virtual COM program to route serial ports on my computer called vCOM. It gives me a virtual pair of ports that are connected together and wired in a null modem fashion. I name my virtual ports ten numbers apart, so for this project I chose 8:18.

That's it!!!! I tuned to 40M PSK31 freq and started decoding. I next tried the transmitter and before you know it I had 1000W of PSK31 blasting out into the universe on the big vertical!!! (I know I just gave some digital joker a heart attack. It was actually 20W) So that's it. I turned on the general decoder in the program and was decoding PSK stations--- bingo. I went to 30M and tried to decode one of those commercial RTTY stations on that band but couldn't get it to work, and my stepper project was calling my name so I'll leave RTTY for another day. There are many digital users on the Flex reflector that use RTTY, PSK, Slow Scan and all of the fancy modes. My point is with the F3K and a couple outboard programs, I had PSK31 working in about 3 minutes and I know exactly 0.0% about digital stuff. That is how easy it is. PowerSDR has a dedicated digital mode with upper and lower sides. If you look at the top picture you can see the digital specific controls. It made it very easy to adjust the various gains in and out of Winwarbler. I think there has been some things done to adjust AFSK so you know what freq you are on in RTTY but I have followed that discussoin only peripherally. Here is some Knowledge base articles about digital modes from Flex's knowledge data base (note there are 3l pages of articles of varying relevance). It turns out there is an article on how to set up Winwarbler, so I'll have to read that sometime.

Here is another shot of the setup this time with all three screens visible and the F3K panadapter shifted to "PanaFall" mode. I expanded the bandwidth 4X on the scope for this view

As I was preparing this screed a fellow dropped me a note because he is considering a F3K and has an interest in digital, so I took the screen shots above and at the top of the page to give an idea of what it looks like. Unfortunately there were only a couple stations on 40 tonight. I hope this simple minded presentation helps him in his decision.