Well I finally got a chance to try the modem. Fired it up and it works fine – on Receive. Very nice and easy to use. The spectral display shows you where all the signals are and adjusting the volume for good copy was very easy. Unfortunately I have a problem on transmit. The CONFIG menu says the TX Audio Level is 0%. That sounds bad

Fortunately, there is a rich resource for help in the NUE-PSK news group (here). I posted my symptoms there and quickly got a detailed troubleshooting guide for my problem for both of the developers of ths NUE-PSK Modem. You won’t get better support than this. Now I have some bench work to do. I am hoping it is not a soldering problem on the Processor. The lead spacing on it is VERY small and I do not look forward to doing any touch-up soldering there.

Well I have been trying to get a WiFi card working with Fedora LINUX, and not having much luck. I tried a Netgear card and a Belkin card. Neither worked because I could not find a LINUX driver. There is a package called NDISWRAPPER that allows you to use WINDOWS XP drivers under LINUX. That sounded like a great answer. Unfortunately it would not build on my Fedora 9 or Fedora 10 (Preview version). So I am off to a new card.

The new card is a nice little USB dongle that does WiFi and has connection for an external antenna. It even has a LINUX driver on the CD. Well, sounds great, but it looks like another battle is forthcoming. The thing works great under XP, and looks like it works with SUSE LINUX on my laptop. I bought it to use with Fedora on my Development machine. First attempts got the basic card working but I had to manually install the driver and configure a bunch of settings by hand. Not what I had in mind, but stay tuned, this may work yet.

Automatic antenna tuners are great. Just tune your radio to the frequency you want, flick the TUNE switch, and you quickly get an optimum match between your rig and the antenna. Well, not always. I have an ICOM IC-7000 with an LDG AT-7000 antenna tuner. This is a great little tuner, but it sure tricked me this time.

I wanted to try my rig on the 6 meter band for the first time. So I set up the station and was listening around for signals during this weekend’s VHF contest. There are some CW beacons I had heard before, so I tuned to that part of the band, activate the tuner, and heard nothing. Then I hit the TUNE button again, bypassing the Tuner, and the beacon suddenly appeared! So I hear no signal with the Tuner doing the matching, but I hear the beacon when I bypas the Tuner.

After noticing that the SWR was indeed lower when the Tuner was inline, I realized what was happening, The Tuner has many memories. If it found a “good” match at a frequency, it uses that information to shorten the tuning cycle next time you go to that frequency. The Tuner had apparently found a match that provided a low SWR, but it also resulted in a lossy signal path. The instruction manual showed me that I could go into the Tuner case and push a switch that would force it to retune, even though it thought it had a good match already. So I pushed the button, the relays clacked, and presto, a good match and the beacon reappeared. Guess this button should be on the front panel! Then I worked my first 6 meter station ever.

Just getting around to continuing assembly of NUE-PSK modem. Latest work included soldering SMT diodes (very small), electrolytic caps, and chip capacitors. These are all 2-lead packages. I found that the easiest way to mount all of these components was to do the following:

1.Put a drop of solder flux on each pad for the part

2. Put a very small amount of solder on one pad for the device

3. Position the board so you can see both of the pads for the device

4. Place the part, making sure both leads line up with the center of corresponding pads

5. Press down on the part, holding it in place and assuring contact between the leads and pads

6. Reheat the solder on the pad where solder was added (the part should now be holding to the one pad)

7. Add a very small amount of solder to the other pad

8. Press on the part and reheat the solder on the second pad

9. Return to the first pad and reheat briefly to make sure a good connection was achieved.

This sounds like alot of work but is really fairly easy. A good magnifying loop, small solder (.015″ or .020″ diameter), and a small soldering iron tip are indespensible for SMT work.

Well I got most of the ICs onto the board. THe first three are fine-pitch (0.5 mm between pads). They were difficult to hand solder. The best approach seems to be the “drag solder” method, where you pull some excess solder across a whole row of pads, then use solder wick to remove any shorts.

The remainder of the assembly should be easy, it will just be a matter of finding the time. Building circuits is not the highest priority in the Summer time.

I now have most of the parts for the NUE PSK modem, so it is time to setup for assembly. This uses SMT parts, so it will require some careful soldering. Instead of starting with the ICs (one-of-a-kind and many leads), I am trying the caps first. Starting witht the 1206 size caps, which are huge by SMT standards, should let me get going with minimal risk.

OK, I got about 10 done. My magnifying light is  piece of junk. It is hard to keep in one place. guess a $ 25 inspection lamp is not adaquate for SMT assembly. But I got the caps down. I had read that I might not need to add solder but that doesn;t work for me. I like to tack down one side, then go back and put some solder on bothe ends. Probably too much solder, but I don’t see how that can hurt anything,

I just heard that L.B. Cebik has died. The amateur community has lost a real antenna expert and a prolific writer. I never knew L.B. but have spent many hours on his website reading his articles, and using his antenna models.

He recently published an interesting article about a short-boom yagi for 6 meters. I wrote an e-mail to him telling him that I found the article interesting, and was thinking about building the antenna. However, I really did not want it for the wide bandwidth that he had in mind. My application was more to leverage the small antenna profile for a high-wind environment. In a day or two, he responded with a slight redesign of the elements to maximize performance in the portion of the band I needed.

Sorry I never got to meet the man, but I know he will be sorely missed in the amateur community.

I’ve been looking for some new wire antennas to try. The Half Square (HS) looks interesting. It is two 1/4 wave vertical elements, with a 1/2 wave horizontal element connecting them. The ARRL Antenna Book has a writeup that looks interesting. I really need something cut for 20 meters and this might be worth trying.

The HS is usually fed at one of the top corners with coax. One benefit is that it is forgiving to symmetrical distortion of the design (like bending the legs due to mounting restrictions). The downsides are that it is high-Q (thus narrowbanded – bandwidth is less than a dipole) and it appears to be a primarily vertical polarity antenna. L.B. Cebick  provides a model of the HS for EZNEC (along with anything else you could ever want to know about antennas). 

What really makes this antenna interesting is the fact that it can be built as a 2-element array (or wire beam). This is attractive to me due to my operating QTH, where only the water is to my East. In any US-based operating, I want to push more of my power to the West. I may also mount it close to the ground, to improve NVIS performance for QSO parties.

The 2008 VA QSO party was held last weekend. with many members of our Fauquier Amateur Radio Association (FARA) club participating. We appear to have better scores than last year, and everybody really enjoyed the activity and competition.

My score was better than last year, but not great (about 300 QSOs). Antennas were the main problem. My one NVIS dipole worked great on 80m, but not very well anywhere else. My 6BTV vertical was useless for this short range activity. Even on longer contacts, the dipole seemed to be better. My all-band COBRA dipole, in an inverted Vee configuration, also did not work very well at all.

See my antenna posts to see where I go from here. Hopefully, I will have some new and improved antennas for next year.

Ham Radio (or Amateur Radio) is a licencsed activity permitting use of the airwaves for communication of all types. There are many different facets of Ham Radio, from talking using voice, to exchanging e-mail messages or files, to exchanging streaming video or using other digital communciation modes. Ham Radio is used by people all over the world.

Unfortuantely, many are not even aware of this hobby. The Internet gets all of the time. and attention of most people interested in technology today. In fact, one person I know referred to Ham Radio as “old man Internet.” Well, there may be some truth to that but ham radio is the Internet without spam, porn, or any type of commercial activity. It is a great way for people to learn about, and experimaent with wireless communications of all sorts.