08 September 2007

Rig and Antenna

Well, finally downloaded the pictures out of my camera. Here's a copy of one of the images, showing the antenna in the background.

In the left foreground is a Shure 444D, which I probably will NOT be taking now, since it weighs in at a couple pounds, and the hand microphone is much lighter. The SWR meter won't likely be going either.

The rig is actually the one that will be traveling with us. In the background, you can see the antenna set up in the yard about 40 feet away. It's 10 feet tall, roughly, and about 14 feet across.

It tested very well, and I was able to tune it down to 1.1:1 SWR at the frequencies I wanted to use. I'll add a few more pictures below, giving some details of the construction of the antenna.

The next image is just of the antenna set up on Saturday, Labor Day weekend. You can see most of the antenna, tripod and a couple of wire dipoles in the background behind the portable dipole itself. The coils are clearly visible here along with the center supporting T-section. Click on any of the pictures for a larger image.

Each of the two pieces of PVC piping are roughly 4.5 feet in length, and they are cut into two pieces each. One of the bottom sections has a pvc coupling glued to it, as does one of the upper sections. The top section, of the bottom half has a set of screw-in adapters, allowing me to shove the smaller pvc piping into the coupling at the mid point. This allows for a heavier (1.25" dia.) lower section, and a lighter piece at the top. I could cut other pieces of piping to extend the height of I wised. I have no intention of taking more weight than I have to though!

Above you can see the details of the center tee-section. An SO-239 connector is mounted physically onto the center of the Tee. On each end of the Tee are bolts, attached internally with wiring that is soldered or screwed down to the SO-239. The end caps are glued on permanently. There are bolts centered on the end caps, which are held with lock washers, flat washers and a set of internal, and external hex nuts. The bolts are actually threaded-stock that is #8, 32 threads per inch. (I think.. I'm writing this from memory, but the thread size is the same thread size that fits an arrow head onto an aluminum shaft.)

The black stripe on either side is electricians tape, and if you look carefully, over the top of the Tee, you will see a couple of fiberglass rods that are connected together, and taped over the Tee, then again taped to the antenna rods (arrows) at either end to give some support to the threaded stock going through the arrows and the Tee-section.

Above you see another view of the center Tee-section, the connector and how I used electrical tape to hold the fiberglass rods to the antenna sections.

Details of the coils. This coil is made from 1.25" OD PVC, with end caps, there are 31 turns of #14 AWG stranded wire wrapped tightly around the aircore. End caps are NOT glued, but taped heavily with electrical tape (in case I needed to later modify things, or I had issues with connectors coming undone). On the ends are pieces of threaded stock matching the arrow inserts I used, held internally with lock and flat washers, and hex nuts, and on the outside as well. The coil wiring is attached internally with small spade lugs, and tightened down very tightly. Externally, arrow shafts are screwed to the end of the coils.

At some point later, I'll do a separate article on details of how to build the coils, the arrows and the antenna parts, then assemble it, but probably not until I get back.

On the left is the actual power supply we're using for the radio. It's going to make a NICE addition to my ham shack (even though JoAnne thinks she's getting it.... :)) It's an alinco, weighs in at about 5 pounds and can handle 32 AMPS! Woot, I can run a couple of rigs at once off that.

Well, that's about it for the day. Enjoy the pictures. Please, if you're reading this, make a comment so I will know and take the survey on the bottom of the page.

Thanks and 73!


05 September 2007

License Update

As of a couple of weeks ago, our daughter, son-in-law and three grand children have temporarily moved back into the house with us, so we've got extra eyes watching for the licensing from Jamaica.

Last Monday, the Spectrum Management Authority contacted me via email, and asked me to go ahead and fax to them the paper work so they could process our licenses, so they would be ready to go when they received the check and original copies.

So, I did that. I'm hoping it will expedite things so that the licenses do come by the time we're ready to go.

Today is 5 September - so we have just over 30 days before we depart. I'm very confident that the licensing will show up before we leave.

More Antenna testing

On Thursday of last week, I pretty much finished manufacturing the parts I needed to assemble the antenna we're planning on taking with us. Thursday evening, I fired up the rig for the first time on Thursday evening and made a half dozen more contacts with it, then Friday even we did more.

Over Saturday, Sunday and Labor Day Monday, I had the rig set up in the back yard on the deck, with the power supply we were planning on using, as well as various microphones. There were no really noticeable differences on audio quality (except when I actually placed the desk mike I was using, a Shure 444D back into High Impedance mode... not sure how I switched that off) and got "Audio is 100% better with that setting".

The normal hand mic seems good enough, and of course it is very light, so it's going. A brass key will go along, but likely will not get used.

I made a couple of dozen contacts from Canada, to Florida, to Bogotá, Columbia and several other places, including Maine, Massachusetts, Texas, and a few other places I can't recall at the moment. Signal reports varied from 5/4 to 5/9 and at least two that were 5/9 +20 db. I am very happy with the testing of the antenna.

The really cool part about the weekend (ok, WARM part!), it was very warm and I had to use an umbrella every day to keep the sun off, and of course, drink a few cold beers to "get me in the mood". We also snapped a few pictures which I will insert in the next few days of the antenna, power supply and the rig. I think I got at least one of JoAnne doing some reading at the rig. Might put that up if she "approves". :)