-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] On Behalf Of jimlux
Sent: Donnerstag, 30. Oktober 2008 15:21
To: Towertalk Reflector
Subject: [TowerTalk] repeating the N0AX/K7LXC studies
Is there any interest in repeating the studies? It's a huge amount of work,
but technology has advanced, both in antennas and in measurement technique.
Seems to me that the big resource consumer is getting and assembling the
antennas (and then disassembling and shipping back to whoever loaned/rented
them). The thought of a multi week antenna assembly fest makes my
fingertips hurt to contemplate it.
With a bucket truck and suitable test site (which I might happen to have
available) the antenna raising/lowering would be pretty speedy. Maybe you
could do one antenna a day. (From sitting on the ground next to the tower,
hoisted up and mounted, spun for the measurements, then brought down).
Maybe a temporary tower or a crane.. Now that I think about it, the latter
sounds attractive. You could put a rotator with a sort of universal plate
mount on the top (or in a 120 foot telescoping boom lift), bring it to the
ground, bolt the antenna on, raise it up.(the bucket truck is controllable
from the ground) No high work at all (which is always slow). It's not all
that expensive to rent a lift for a week.
(or actually, we essentially have this on the antenna range at JPL..A big
boom that can erect and has a precision rotator on the end of it. We use it
for testing VHF and UHF antennas with a huge log periodic or horn as the
probe. I wonder if we could permission to use it?)
Jim, W6RMK
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If not having the 2nd antenna in the mainlobe, either to receive the test
signals or to transmit one, all results well be misleading and it might
happen that the worst antenna gives the best result.
That 2nd antenna postion must be pretty heigh.
Lets say the antenna to be tested is at 10m height for the 20m test, then
the other antenna 100m away must be about 55m up!
73
Peter
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