Please see the follow-up post on this topic.
I’ve had a rough battle with my lungs and throat over the past few months, which makes it quite difficult, and sometimes painful to talk. Such is the case this week. I haven’t been on the radio much because my favorite mode is phone. It’s nice to be able to talk to someone in another part of the country. You get to hear their perspective on things, what’s happening in their part of the country, and sometimes that person inspires you to try something new! This does not mean, however, that I’m opposed to, or wouldn’t use other modes.
I’ve been meaning to try PSK31 for some time. I even downloaded the software on my Mac awhile back. I decided this week that I would give it a try, simply because I couldn’t talk with ease. But, I had to do a few more things before playing radio without my voice.
A few weeks ago, I purchased a RigBlaster Nomic to interface the computer with the radio. At the time of this post, it’s the least expensive of the RigBlaster models, and it’s quite compact, both of which were huge selling points for me. Like a lot of hams, having enough space in my shack is an issue. A few days after it arrived on my doorstep, I proceeded to assemble the RigBlaster. Yes, some assembly is required, but it’s very simple. the directions provided by RigBlaster are very easy to follow. You shouldn’t have any problems. If you’re like me and have a hard time seeing the fine — or small — print on a lot of things, a magnifying glass will come in handy. You won’t need the magnifying glass for the instructions, but you may need it for assembling the controller. The RigBlaster Nomic comes with a RS-232 male to USB cable, two audio cables with 1/8-inch stereo male plugs at both ends, jumpers that you’ll need to set to interface the brand of your rig (Kenwood, Yaesu, ICOM), to your computer, the instruction manual, an 8-pin round female mic adapter, an 8-pin RJ-45 mic adapter, some double-sided tape, and four adhesive feet so that you can either mount or set the control box down on a hard surface. It also comes with a CD-ROM with several programs for the various digital modes that you can use. The CD-ROM also contains drivers for the RS-232 to USB cable. Yes, there are drivers for Mac OS X, but you’ll have to browse the CD-ROM to find them. Once you do find them, the drivers are very easy to install. No command-line or terminal needed! You’ll want to install the drivers BEFORE connecting the RS-232 to USB cable to your Mac. For you Windows users, step-by-step instructions are in the manual. Follow them to the letter.
The controller is nothing more than a small metal box containing a printed circuit board with a variable resistor, audio in/out jacks, the female RS-232 port, and the female RJ-45 port. Inside are a number of jumper pins, which you will use to set the controller to operate your rig. The jumper settings for the most common manufacturers are towards the back of the supplied instruction manual. If you have an “oddball” rig, check out their website. You may find the jumper settings there.
Within ten minutes, I had the controller assembled. That was the easy part. The not-so-easy part was calibrating the rig and the the sound output from the computer. This is not RigBlaster’s fault, by any stretch of the imagination. I just ran into a few snares. I’ll explain.
I successfully installed the RS-232 to USB adapter onto my Mac without any hangups. The drivers are contained in a .dmg file, so it’s just a matter of opening the file, and clicking on the package to install the drivers. You’ll be prompted to restart your computer. Once you log into your computer, you can go ahead and plug the cable into any available USB port.
The next step was fairly easy as well: calibrate the rig with the signal being generated by the computer. I use a program called FLDigi. It’s very easy to use and can be installed on Mac, Windows, and Linux operating systems. You can download FLDigi here. It’s free. I also suggest you read the Beginners Guide to FLDigi. Within a half an hour, you should be up and running.
FLDigi has a nifty “tune” button. This generates a tone so that you can properly calibrate the output of your transmitter. It’s also conveniently located AWAY from any other buttons that you’ll use while on the air so that you don’t accidentally press it.
The Kenwood TS-440 allows you to manually activate the transmitter for an unspecified amount of time with the push of a button. You then have both of your hands free to make any adjustments necessary. I calibrated the rig so that no more than 30 watts of power was used when transmitting the signal. The next step is where the complications began.
I needed to find a way to key and unkey my transmitter at a specified time. As mentioned in a previous post, I tried to write a script that would do this on my Mac automatically when I told the computer to do so. Writing code to key the transmitter was a breeze! The difficulty came when I tried to write code to unkey the transmitter. That was much more difficult. I never did get that figured out.
With the help of a local ham, I was informed that I could use the VOX circuit in my radio to automatically key and unkey the transmitter. Brilliant! So, I tried to calibrate my rig with the signal generated by the computer. There was a bit of a problem. The variable resistor on the RigBlaster control box was way too sensitive. I was either putting out 70 watts, or nothing. I thought that maybe I could adjust the sensitivity of the VOX circuit. That didn’t work. I tried adjusting the Anti-VOX portion of the circuit. No luck. I also tried to adjust the output volume in the control panel. That didn’t work very well, either. It generated some results, but again, the variable resister in the RigBlaster was far too sensitive. I was stumped. Then, it dawned on me. What if I purchased a simple, low-budget audio mixer to manually adjust the audio output? I found exactly what I was looking for on Amazon.com: The Pyle Pro PDMX4L four-channel audio mixer. I really didn’t need this many inputs, but it was the least expensive one out of the bunch, and it operated on a 9-volt battery, or the optional 9-volt AC adapter.
I put the mixer in-line between the Mac’s sound card output jack, and the RigBlaster Nomic’s input jack. I opened the variable resistor all the way on the controller to allow the signal to pass through. I again tried calibrating my Kenwood using the signal that was generated by the computer. It worked! I’m using just under 30 watts of power, and the VOX circuit was able to detect the signal without any problems!
If you choose to use the VOX circuit in your rig like I did, you should be aware of a few things:
1). You won’t need the RS-232 to USB adapter cable. One less cable is always good. I plan on keeping it connected to my computer, though, because I can use it for my 2-meter/70 cm transceiver for Packet or APRS. Did I mention that I love purchasing things that serve more than one purpose?!
2). This is probably the most important point: MAKE SURE you DISABLE the system sounds on your Mac, Windows or Linux computer. You don’t want these sounds going over the air when you transmit. For one, it would cause harmful interference on the band, and since most of the sounds that come out of our computer sound like “music,” they shouldn’t be transmitted on any of the amateur bands. This is simple to disable on the Mac. Go to System Preferences>Sound>. Make sure the check mark is removed from the boxes next to “Play user interface sound effects,” “Play feedback when volume is changed,” and “Play Front Row sound effects.” You’re all set.
3). DON’T listen to music, or any other audio file on your computer while operating PSK31. Remember, you’re using the VOX circuit on your rig, and any sound generated by the computer will automatically go over the air.
Last night, I really had an itch to get on the radio. I thought I’d try PSK31 and see how well things would work. I tried to answer a CQ, but didn’t get anywhere, so I thought I’d throw out a couple of CQs on my own. WB4MOR answered my call! Copy was perfect on both ends! I was ecstatic! I wanted to keep playing, but it was getting rather late, and figured I should probably continue to rest and go to bed.
PSK31 is definitely my mode of choice right now … at least until I can talk comfortably again. You can get in on the fun, too! If you have an HF rig that operates in SSB mode, and a computer, you have to two biggest components of PSK31. Tune up, get on, and have fun on this very efficient mode!