Dick Green WC1M wrote:
> Hi all,
>
>
>
> I've trammed antennas 7 times over the past 18 months: a 40-2CD up and down
> (the latter just today), plus three 4-el SteppIRs up and one down and back
> up again. I'm still not satisfied with the sling technique I've been using
> to support the antenna while tramming, and I'd like to hear what techniques
> others are using.
>
>
>
> What I do is take a couple of 4' nylon climbing loops (22kN) and secure them
> to the boom as far from the center as I can reach. I wrap each loop around
> the boom, passing one end of the loop through the other and pull until the
> strap is tight against the boom. Then I connect the two over the center of
> the boom with a carabiner, which is where the trolley and pull rope or
> come-along attach. I adjust the distance of each strap from the center until
> the antenna is balanced. For some antennas I could use a single strap at the
> center of the boom, between the boom plate u-bolts, but I feel the two
> widely separated straps distribute the load better.
>
>
>
> My techniques works OK on a relatively light antenna like the 40-2CD, but I
> found the heavier SteppIRs have a tendency to rotate in the straps i.e., the
> boom rotates) When that's happened, I've had to secure the straps with hose
> clamps, but I think this is a bad idea because hose clamps have sharp edges.
> I'd like to find a better way to secure the straps to the boom. Also, I'd
> like to have the center carabiner as close to the top of the boom as
> possible (now that the tower is fully populated, antenna booms have to tram
> over the elements of other antennas, so the close the boom is to the tram
> line, the better.)
>
>
Depends on how far off center the center element is located. How about
a half hitch or several around that element with the rope used to lower
the antenna down the tram line. That should leave the elements
paralleling the tram line. When close to the ground the ground crew
catches the ends of the elements and lets it settle horizontally.
When raising the antenna who ever is on top simply slips the half
hitches down the element toward the boom. Once the rope is released the
half hitches which are now up to the boom can easily be removed.
I haven't tried this with any really large antennas, but it certainly
works with the tribander and the nearly 30' long 6-meter yagi.
73
Roger (K8RI)
>
>
> Soon I'll be tramming the heaviest antenna I've attempted: a Cal-AV 2D-40A,
> at 17 sq ft wind load and 165 lbs. Needless to say, I'll wait for a calm
> day. But with such a large antenna, I want to make sure the sling technique
> is as sound as possible.
>
>
>
> Please let me know how you sling your antennas for tramming.
>
>
>
> 73, Dick WC1M
>
>
>
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