[aprssig] APRS Irrigation Pipe 55' mast

[Robert Bruninga]

Thanks for the feedback.  Ill clarify the wording.
Its 3 sections of the standard 2,3 and 4" irrigation
pipe.  And probably mine is about 50'.  I can't
remember if I got full 20' sections of pipe or
the more likely shortenend ones due to damage.

But I think I remmebr that some perfectly good 
looking 20' pipes were still not-useable by the
park rangers due to just damage to the fittings only.
I have another one of these antennas on my
house in Annapolis (2 sections) but it is rental
and I havent used it in 20 years.  It also came down
in a thunderstorm, having the top section bend at
the base.  I spliced it back together too.

Again, never leave one of these unattended in bad
weather OR be sure to guy it.

Oh, I also shoved hard foam up inside that splice
of the top section of that one, to make it less likely
to kink near the base.  Probably would have been
better to run up a 6' piece of PVC inside the bottom
of it where the bending moment is the most.

Oh, the PVC pipe does not fit as is.  You have to split it
and compress or expand it to fit where you need
bushings...

Thanks
Bob
>>> ramirault at verizon.net 05/08/06 8:36 PM >>>
>Bob, you were not clear on the pulleys and how they 
>were used.  You said ..  "There are three pulleys, 
>two at the top of the lower two sections and one 
>at the bottom of the middle section."

>But, you didn't say (or maybe I missed it) how many 
>sections there were.  Without knowing how many 
>sections the placement of the pulleys does not make 
>sense.
>
>There must be at least 3 sections (because there is 
>a "middle" section) but there also could be 5.  
>If there is 3 then the middle section is also one of 
>the "lower two" sections and has a pulley on both 
>the top and bottom.


----- Original Message ----- 
From: "Robert Bruninga"
Subject: [aprssig] APRS Irrigation Pipe 55' mast


For 20+ years, people have been asking me to  document
my very lightweight 55' push-up mast that I use for APRS
field events.  So I finally took some pictures Saturday while
doing some long overdue maintenance for this years  Field Day:

http://www.ew.usna.edu/~bruninga/Antenna-Ipipe.html 

WIth a 15' marine fiberglass whip on the top, it gets me to
70 feet in only a few minutes and only weighs 35 lbs.

Just thought I would share it for anyone else that likes to
tinker...  Built it with only a hacksaw and stuff lying around.

de Wb4APR, Bob



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