The AM Forum

I had a chance today to repair a little fan dipole that I use on 20 and 17 meters. I ended up using the 4" length Fi-Shock high-voltage ribbed insulators mentioned to me by Peter N2IDU. I was very impressed with how rugged and rigid the material is. Construction was easy and fast:

1. clamp each insulator into a vise by one of the ribs
2. Drill a 1/8 inch hole at each end for the wire
3. Use a pair of wire cutters to slot each hole to the end of the insulator
4. Snap them onto the parallel wires and space them evenly
5. Walk along with a hot glue gun and fill up the end of each insulator

The end result is really strong. I'm going to re-do my open wire line with these things when I get a couple of sunny days in a row. The insulators cost less than 20 bucks for a box of 200.

http://www.fishock.com/store/high-tensile-electric-fence/500-540

Rob W1AEX

Hi Rob
I bookmarked the website for future reference in case my spreaders start dying on my open ladder antenna system. I have gone through two Western Pa. winters and no failures.
I am using the W7FG ladder line/antenna. It's one continuous wire from shack to the end up in the trees. He used another material for spreaders that surprisingly has held up very well .

It must have increased my signal by 10 dB from when I first went on the air here in Pa. from my Maryland QTH.
Splices and really crappy soldering joints that never had a good flow, and me not using Silver solder was the down fall from the original antenna. So I'm not saying this antenna has miracle wires. And that 600 ohms was another wonderful discovery compared to the 450ohm design.
Maybe an easier or efficient match for the tuner.
Thanks
Fred

Hi Fred,

I've never heard any complaints from the guys using the W7FG ladder line/antennas. My guess would be that yours will be up there and working fine 20 years from now.

This past February I watched as 60 mph gusts of wind destroyed the fan dipole I made 3 years ago. The spreader at the end snapped, so the northern end of the 17 meter element started whipping back and forth. In about 15 minutes the wind worked it's way to the feedpoint, snapping the spreaders which were spaced 12 inches apart, one at a time. When I lowered the antenna to repair it, I found to my horror that the tubing I had used was totally fried by UV. It had become extremely brittle and snapped very easily. Obviously that tubing was not UV resistant! My feedline for the 250 foot center-fed uses the same tubing, so needless to say, I want to replace it with new feedline made up from the fi-shock insulators ASAP.

Only time will tell how these will hold up, but they are very rugged, rated for high voltage, and black polyethylene is supposed to have high resistance to UV. That makes sense since they are made for outdoor fence installations in a high voltage application.

I've been told that you can buy these from Tractor Supply outlets. That might save a few bucks as the place I mail ordered from charged around 8 bucks for shipping, which made the total around 26 bucks for a box of 200 insulators.

Rob

 

The w7 stuff were home brewed out of 3/4 black pex underground flexible water line.. 100 ft roll is about $40.  cut it to length and cut a v groove in the ends..  the only problem is its not uv rated.. the electric fence stuff is.. Not to mention its a lot lighter.

Hi Rob and Fred et al .... thanks for passing along the tip .... found them yesterday at Tractor Supply in bags of 25 for $2 ... look like licorace twizzlers ...yummy ....73 ....John