Friday, July 31, 2009

More Digital Fun

Well, I finally got around to playing with FLDIGI again. I hadn't been able to get it to work with the IC-7000 but I tinkered enough tonight and got the rig control working. I still need to tweak the macros and figure out a few things but it seems to be pretty slick. Now that I have it working I'm one step closer to getting the NBEMS stuff going.


I really want to see about using this on a Linux-based netbook so I was pleased to finally get it working. Hopefully I'll have the chance to get it all setup and configured this weekend. I'm keeping my fingers crossed!

Tuesday, July 14, 2009

A Birthday w00t!

Ok, for those of you not in the know, "w00t!" is a good expression. A couple of days ago my bestest brother (never thought I'd ever say that :-) ) surprised me with a package in the mail. When I looked at the label I saw it was from Powerwerx. Backing up a bit we've been working out or communications abilities between our locations using various digital modes. I'd operated during Field Day on battery power and hadn't re-charged a week or so later. Well, when we tried to play the battery was too pooped to party. He asked if I had anything to monitor the voltage and I said I wanted to get a good gadget but just kept using the multimeter and hadn't checked it lately.

Coming back to the present time I opened the box and found a Whattmeter. I said, "w00t!" This thing is pretty slick. It gives you current and average amperage/voltage along with power consumption. Now I can compare the amperage my radio is drawing with what the manual states. I'll be able to use this data to make more accurate power plans.


The Whattmeter is small, too. It also came with Anderson Powerpoles so it was installed in seconds. So big birthday thanks to my big bwudder.

Sunday, July 12, 2009

NVIS Update

I finished the HF NVIS antenna last week and used it to check in to the North Florida Phone Net on 3950. My friend Bill was running the net that night and the first thing he did was tell me how good my signal was. I was very happy to hear that. Here's a little rundown of how I put the antenna together. The design is based on the AS-2259 military antenna and can be found here.

The 15' mast is made of 3 5' pieces of 1.5" schedule 40 PVC. I used an end cap for the antenna connection. The hardware is brass for conductivity. Here's the cap before assembly.


Holes are drilled. The S0-239 needs a 7/8" hole. The other holes are sized for #6 screws.


The original plans called for the head to be cut off a #6 screw with the end inserted into the center conductor of the SO-239. I don't see how this is possible as there's no way I see it fitting. I scaled down to a #4 and it fit fine. Here is the assembled cap.


I used a 2' piece of 3/4" rebar to stabilize the mast bottom and keep it from kicking out. Here it is with the bottom section in place and the other two on the ground. I originally started with #18 stranded copper wire but it proved to be horrendous to work with. It knotted, kinked, and twisted to the point of being unusable, at least for this project. I have since switched to #14 insulated stranded which seems to be working much better. Each side of the antenna has two wire runs of 38' and 25'. These terminate at dogbone insulators but you could just as easily use some PVC if you have it laying around.


My feedline is RG-8X and it enters the bottom of the mast through a 3/4" hole and travels up to the SO-239 in the cap.


There was (imho) a design flaw that presented itself early on as I started to raise the mast. The PVC couplers used to join the mast sections didn't provide nearly enough support or rigidity. As the mast went up is leaned and swayed every which way until the top section finally fell off. I panicked since it was the holiday weekend but I managed to slip into Ace Hardware before the closed. I switched to threaded couplers and they provide a great deal more support. Keep in mind that nothing is permanently attached. I didn't glue any of the parts together. I may in the future but for the moment things seem to be fine without it.


After the first night on the air what I thought to be another major design flaw proved to be true. I awoke to find the antenna leaning severely and thought that the stakes holding the legs out had come loose. Instead I found that the center conductor and screw had broken off. I never really understood the logic behind putting so much stress on the connector. I came up with my own design mod and it seems to be better and stronger. I drilled a hold in the side of the cap where I ran a 1" #6 brass machine screw. I then used about a 4" piece of #12 solid wire that I soldered between the center conductor (using a new connector) and the new screw. Now the heavier screw can take the stress without straining the connector itself.


This is what the latest mod looks like with the legs attached.


You may have noticed that I also decided to paint the mast so it blends in better than the stark white PVC. I used Krylon's Fusion Camo paint. It's supposed to bond to plastic without primer but it seems to scratch off the PVC very easily. Time will tell how well it really holds up.

Here is the finished antenna after the mods and paint job.


And finally the cap and legs.


It's been a fun project. My next goal is to model the antenna. Stay tuned for that.

Sunday, July 5, 2009

Independence Weekend

Happy 4th of July!! Drat, it was yesterday already. :-/

Since I had Friday off for the July 4th weekend I started working on a new antenna project. I'm building a HF NVIS antenna. I battled some weak structural integrity on the PVC mast due to the couplers not holding enough. I made it back by Ace Hardware just before they closed and got threaded couplers instead. They seem to add enough rigidity to keep it fairly stiff. It will still definitely have to be guyed.

I also made the mistake of using some 18-ga bare stranded wire from Home Depot. I thought it would work well but instead I ended up with a horrible rat's nest of wire that I'm tempted to just throw in the trash. The stuff knots, twists, and kinks horribly. I replaced the four runs with my 14-ga jacketed and it works much better.

I ran out of time today to get it on the air so hopefully I'll have an update tomorrow.

Right now I'm in the middle of my first digital contest. I'm participating in the 070 club's 40M Firecracker Sprint. Due to late birthday festivities I missed the first 1.5 hrs and I'm giving the rig a break to cool down a little now. The temp gauge looks fine but my output power is being reduced so I felt it prudent to let it breath a little.

I'm not getting anywhere near my goal of 100 contacts but it's still fun. If I get 40 I'll call it a success. It took me a few QSOs to get the contest macros worked out. I can still do a little tweaking but so far I'm not doing to bad I guess.

Well, I'm going to give it another shot. Wish me luck! :-P

Friday, July 3, 2009

Field Day Follow-Up

Well, I'm finally stopping to take a breath and can give my after action report on Field Day. The first joint exercise between Duval County ARES and the Beaches Amateur Radio Society (BARS) was a resounding success. Our estimates (not everybody signed the roster) have us at about 60 visitors. I'm still tallying the logs but it looks we have about 300 contacts. Not bad for some leisurely operating.

I really was surprised by the number of people that came out. We had the largest waterspout (later deemed a tornado) on Friday night and the temps were in the mid to high 90s on Saturday. It didn't seem to keep the people away though. Fortunately we'd also fogged several times and that kept the bugs at bay.

We operated as K4D and were 5A. The plan was to operate 160, 80, 40, 20, and 15. I was assigned 15M but I was so busy running around that I didn't really operate there much. By the time I could sit down nothing was happening so I moved to 20. Here are some of the guys setting up the "true" 20M station's rotating dipole.


We ran a variety of antennas in addition to the rotating dipole. We had a couple of wire dipoles that had been built by the Jr ARES youth during their meetings. We also used a G5RV from the UASI grant money, and below are some of the BARS members assembling their June meeting project, a 20M Moxon antenna.


We started serving dinner at about 5 and everyone had a good time. The Red Cross brought out ice and drinks and others brought out various picnic items. This sort of gives you an idea what type of crowd we had. We certainly didn't expect to have a parking problem. :-)



With everything that was going on it was time to get some media coverage. I had contacted our local CBS/Fox affiliate and they came out just before dinner and stayed for a couple of hours. During the time they did some live interviews, shot video for later broadcasts, and even did a live feed. Throughout the weekend they aired three stories about the event. We couldn't have asked for better exposure and publicity.


I finally got to start operating around 4:30 Sunday morning. It was the first chance I'd had to really do anything other than run around. Of course I did take a little nap from 1 to 4:30. The bands were open and 40M was really hopping. I was only interested in working digital and knocked out 57 PSK31 contacts in the short time I had. I enjoyed a nice sunrise while the bits were flying.


We've really set the bar high for next year but I already have ideas bouncing around in my head. Can't wait for 2010!