Eric,
Sorry to take so long to reply. I fell behind in my CQ-CONTEST reading.
There are two kinds of rivets used by Force 12:
Closed-End Open-End
------------ ------------
|
|
| <--Steel mandrel is pulled up. It pulls
| aluminum up and breaks off.
| (mandrel removed)
----- ----- ----- -----
| | | | | | | |
| | | | <---solid aluminum, | | | |
| | \_/ fills hole. Doesn't | | /---\
+-+ elongate. +-+
Before After Before After
Normally, the closed-end rivets are used for permanent installations
(they can easily be drilled out when you need to disassemble the
antenna). Rivets don't cost much (about 8 cents each for the big ones).
For temporary installations like the CE0Y DXpedition, the plan was
just to use uncrimped open-end rivets, held in place with heavy tape.
No good for a permanent installation, but OK for a weekend-long
contest. Each element taper gets three rivets.
I do not know if they actually did it this way (I wasn't there) but
that was the plan. Nice thing about this technique: no tools of
any kind required to assemble the elements, not even a pliers! All
holes are pre-drilled, so you don't need a tape measure either.
For those viewing the above drawings on funny terminals:
"|" is a vertical bar
"/" is a slash
"\" is a backwards slash (backslash)
---------------------------------
160 meter antennas on small lots.
---------------------------------
I live on a small suburban lot. I shunt-feed my 89' crank-up at the
base. Tower is grounded with four 8' ground rods and some heavy braid,
but no radials. I seem to get out really well. Ground conductivity
is very good here in Silicon Valley -- must be all the silicon! ;)
Receive antennas are a big problem, because I have no room for a
beverage. I use a small indoor 4-turn receiving loop from July, 1977
QST, page 30, with an Industrial Communications Engineers 20 dB 160m
pre-amp. With the loop I can null-out the heavy line noise that
is being re-radiated by my tower. The loop has a bit better S/N
ratio than receiving on the tower, but even with the pre-amp most
signals barely move the S-meter. Guess I may have been an alligator
(all mouth and no ears) to some, but hopefully not to too many.
Finished with 409 x 66 = 53,988 (slept through the JA runs both
mornings; big mistake).
73,
Bob, N6TV
|