As someone who has installed thousands of "pop" rivets both with manual
and pneumatic guns I can attest to the efficacy of putting all or most
rivets in their holes before popping them or distortion may interfere
with putting them in later necessitating a little reaming to fit them in
and that little reaming is a bad thing. Another approach that is useful
when able and applicable is to not drill all the rivet holes before
installing any rivets. Install enough rivets to hold the parts in
proper relationship and then drill the rest of the holes and put in the
rest of the rivets.Do not oversize the drill bit. For 1/8 inch rivets
9/64 is the largest "good" sized hole.
Patrick NJ5G
On 3/9/2016 10:59 PM, Roger (K8RI) on TT wrote:
It would certainly seem like it, but I'm not so sure. Most of the
better antennas work well once tuned up and may work great for some
years. The C3i antennas were great performers for some years. Yet
when taken down, the coax match on all had the solder dissolved to the
point where the matching section was no longer connected. They would
have stayed up for 4 or 5 more years before they failed, but a flock
of Cormorants decided "THAT C3i 7L 6-meter antenna" was going to be
their roost. So I think failures are often attributed to the weather
or age rather than design.
I found a broken element tight at the first rivet on the C19XR.
Admittedly it was from rough handling. My wife had some neighbors
move the antenna (on saw horses) when I wasn't available to help.
Holes in elements weaken them at that point, so I'd want that first
rivet a little farther back so the larger tube would support the
smaller at the weakest point.
Loose rivets? I wonder if that was an installation problem? With pop
rivets even cleaning the hole out with even a 1/64th over size drill
would likely be a source for problems. Pop rivets should be snug. If
installed one-at-a-time the following rivets may not want to go in,
resulting in a hole being redrilled
73
Roger (K8RI)
On 3/9/2016 Wednesday 8:21 PM, Kelly Taylor wrote:
Isn’t a lot of this talk a bit of picking the pepper?
If joint conductivity of aluminum elements was a serious issue,
wouldn’t we have heard something about it in the, what, 60 years
we’ve been using aluminum tubing for antenna elements?
73, kelly, ve4xt
On Mar 9, 2016, at 6:36 PM, George Dubovsky <n4ua.va@gmail.com> wrote:
If you weld the aluminum tubing, you destroy the heat treatment in
the Heat
Affected Zone, resulting in a much weaker element.
73,
geo - n4ua
On Wed, Mar 9, 2016 at 6:43 PM, Tom_N2SR via TowerTalk <
towertalk@contesting.com> wrote:
If you weld the tubing together, what is the wind rating then?
Kind of
difficult to get apart, but very little risk of losing electrical
contact,
rivets failing, rusted screws, etc.
Someone should try it and report their results.
Tom, N2SR
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|