Well, I've answered my own question: the AB-577 extension kit for 75' can be
installed by one or two people, as long as you carefully follow special
procedures outlined in the manual.
W1ECT came over today and we raised the AB-577 to 75 feet. There was a 5-10
MPH wind blowing that sometimes complicated matters -- it would have been
easier and less scary had there been no wind at all. As expected, it got a
little hairy after the standard 50 feet: at times the mast would bend way
over to one side. At that point, we decided to go with the procedure
outlined in the manual for times when the wind is blowing and the guys
aren't manned. This consists of snugging the top guys, paying out 2-4 feet
of cable on each of them, then raising the mast until one of the top guys
gets so tight that the mast starts to bend again. The mast does tend to bend
while doing this, especially when there's a gust of wind, but it doesn't
bend so much that there's danger of the spring clips breaking. One of us
would then run to whichever top guy was tight and pay out enough cable to
get the mast closer to vertical. Then the mast could be cranked up again.
About two sections from the end, the upper set of middle guys came into play
and had to be gradually adjusted along with the top guys. The only
difficulty was that one of the top guy snubbers was very hard to close,
which had to be done frequently.
You really have to take your time, raising the mast slowly while constantly
checking the mast. Sometimes it will go up several feet before the guys need
adjusting, sometimes only a few inches. Mostly, that was caused by
variations in wind speed and direction. I didn't record the time, but I
think we spent at least an hour on the last four sections. Obviously, it
would go much faster with a man on each guy, but it's really not so bad with
two people. It's possible to do it with one person, but it would take a lot
longer -- lots of running, too, so you have to be in reasonably good shape.
73, Dick WC1M
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