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Easy peazy 80 meter...
 

Easy peazy 80 meter sloper for field HF radio.

 

(@ve6jhk)
Joined: 12 years ago
Posts: 9
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For a simple top fed sloper, all you need is a way to get a fishing line or parachute cord high up on a support to pull up a coax cable a driven wire, and a counterpoise wire. A tree or anything can be used as a mast. In fact, a fishing pole was used with a lead sinker to fire a pull line up over tree limbs. This was used to pull up the parachute cord support line. The support line pulled up the driven wire, feed line, and counterpoise.

In this case, a set of six x four foot socketed tent poles were used as a mast to push an RG-58 feed line, a 66 foot driven wire, and a ~66 foot counterpoise up in the air through the ladder on the back of an RV (one section at a time was added from below). All that was used for wire was a single strand of 24ga copper wire, which was purchased as two x hundred foot spools for the princely sum of $8.00 each.

No balun was used, and the counterpoise just followed the mast down, with the excess routed wherever there was room to accommodate the extra 40 or so feet. In some locations, the extra 40 feet just zig-zagged wherever to use up the length. I kept the counterpoise higher than 7 feet so no-one would contact it. The far end of the driven sloper wire element was supported on two lengths of tent pole for 8 feet of height above the ground. Sometimes it was supported by tent poles stuck in a stake pocket of the truck, and other times tent poles were bungee corded to a stake or post. (Tying cords to trees is discouraged at most campgrounds). [In the mountains, I have heard of operators just throwing a driven wire over the edge of a cliff or bank, and running a counterpoise wherever].

The SWR was adjusted to resonate on the low 80 meter band by folding back the end of the driven wire on itself to shorten it. At resonance it matched as close as 1.2/1, which was very good. A manual tuner was used to widen the operating band, and surprisingly; the sloper tuned up on all bands and worked just fine. (Perhaps the current on the feedline shield became part of the radio wave radiator).

The sloper tended to give almost an S-Unit of extra receive gain better than the Hustler Mobile antenna, on all bands. Signal reports coming back confirmed that it was the better radiator as well! An S-Unit is big news especially when working QRP, since you are operating just at everyone else's noise threshold at the best of times.

When the antenna was dismantled, the mast sections were lowered and removed from the bottom of the ladder section at a time. the wires were wound around a piece of cardboard with notches cut in the ends to keep the wire in an orderly "coil" for easy re-deployment.

VE6JHK

This topic was modified 11 months ago by VE6JHK

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