80 Meter Carolina Windom using the Wireman 24 gage FLEXWEAVE™
My latest push up pole is from The Mast Company. Thicker and longer than my other MFJ mast it still bends quite a bit at the top so you need to be careful how much wire you hang on it and always extend it by pushing it up vs. tilting it up.
The base of the mast is held in place with an RV flagpole mount I got at the SD
County Fair. It fits under a tire and has a tube the mast (flag pole) fits into.
I use PVC pipe sections to match the diameter of the mount to the smaller size of the Mast Co. 33' push up mast.
Click here for the vendor.
Above a home made version of the tire mount. The flat part was laying around the barn. It could be duplicated with anything sturdy enough not to flex. Attached to the "tire holder" is a hardware store pipe flange. Screwed into the flange is a piece of pipe screwed to a female plastic PVC connector. Glued to the PVC connector is a length of PVC pipe to drop the push up pole into. Adjust your PVC pipe sizes to accommodate your push up pole diameter. Here the MFJ push up is installed. This rig stays in my truck.
I attach a chain repair link to the ring provided on the push up mast. This is the 40 Meter wire that is several feet longer than the pole considering the other end is attached to the ball mount on the roof. I tie the extra length to the pole and the match appears fine. I may try to run it down the guy wire when I use a guy. The wire is FLEXWEAVE™ 14 AWG, 168 strand bare copper ultra-flexible antenna wire from the Wireman. The Velcro straps are to hold the feed line to the mast when I use my 80 Meter dipole setup.
Going up with a dacron guy attached
40 Meter wire extended. Again, as in the NVIS setup, the truck is the other 1/2 of the vertical dipole. Use the old 468/Frequency in MHz to determine the length of the wire. Cut long and tune. I was able to get under 2.1 VSWR over the General Phone portion of the band. This day I had about 20 mph wind gusts so I put a dacron guy opposite the antenna wire. Note the top flex on the pole. I think I will try 24 gage wire in the future.
Here is the 20 Meter wire up. This one is using regular 24 gage, stranded, hook up wire. It tuned very well over the General portion of the 20 meter phone band.
My Wireman order arrived! Armed with the specifications for a compact 4 to 1 balun from QRP. I proceeded to build my 80 Meter Carolina Windom, a smaller version of my 160 Meter base antenna. NOTE. This construction is not intended for a long term up antenna. Most of the time it stays in my go box for use motorhoming or emergency communications. When I get through I will probably RTV some of the connections but the goal is a very light assembly as the fiberglass push up poles tend to flex when they have a lot of weight on top. Another good discussion on Windom antennas click here. and here.
My first try balun, front. Not finished yet.
Torrid is a T106-2, Wireman Part # 903
First try, rear. Mount is one of those throw away putty knives
Second try, finished. Here you can tell it's a throw away putty knife. The material is easy to work with, cheep, and should hold up well with my temporary use. I decided to add terminals for easy of assembly and future repair. The coax is attached on the back side with the shield soldered to the ground windings on the balun and the coax center to B2. B2 and A1 go to the wire.
The formula to compute the length of the wire is the standard 468/frequency with the 4/1 Balun at 62.2% from one end. ( WM6Z from Imperial says he moves his balun around till he gets the best VSWR with his analyzer. Why didn't I think of that? ) The wire is Toughcoat 'Silky' 26 AWG, 19 strand 40% copper-clad steel from the Wireman # 534
Current balun made from 6 clamp on torroids from the Wireman part # 916. The RG58 feed line is looped through the torroids 3 times. As I have stated in my other pages, my current balun's are somewhat a guess from looking at many articles on the internet. You know they work when your tuner tunes properly. When they don't your tuner does a long mad hunt and never seems to settle end. Common mode current? ( Also see The Saga of the Balun )
In the air on the Mast Company 33' pole. Tuned well on 80M and acceptable on 40 and 20. Higher VSWR's were compensated for by the LDG 7000 tuner.
VSWR and more for the finished 80M Carolina Windom
( Adjusted for the General phone upper portion of 75M )
Frequency MHz VSWR Rs Ohms Xs 3.8 1.7 71 26 3.9 1.4 41 15 7.175 2.4 20 11 7.3 2.5 20 11 14.35 2.7 31 28 For data on my base 160M Windom follow this link.
NVIS
The Windom also makes a very good antenna for local communications using NVIS. "Near-Vertical Incident Skywave (NVIS) is a combination of radio hardware, skywave radio propagation, operating procedures, cooperation, and knowledge used by a group of radio operators who need reliable regional communications. It fills the gap between line-of-sight groundwave and long-distance "skip" skywave communications" Follow this link for a discussion of NVIS and links to more articles on the subject.