"Tom Horne" wrote in message
news:0Z9Zi.79$Y32.0@trnddc04...
Mike Kaliski wrote:
"Tom Horne" wrote in message
news:Md4Zi.36$WN2.29@trnddc08...
Is it possible to ask questions here without triggering an arcane debate
about competing views of theory. I'm about to find out. I asked
earlier in another thread what measuring instruments I would need to
have the use of in order to compare the effective radiated power of
different antennas. As near as I can tell there was no answer.

I built a collinear J pole using copper tubing. I'd like to know if it
is more or less effective at radiating whatever works to the stations
I'd like to be able to talk to under conditions of emergency operation
then say a collinear ground plane or any other omni directional antenna.

I would like to deploy the most effective practical antennas that field
testing can devise and not have to wait until the next breakthrough in
physics to be able to get my local governments Email out to my county's
government, the state government and the responding relief forces.

My question, again, is what measuring instruments can be effectively
applied to the comparison to provide results that will be born out by
real world performance. I have to admit that I find the endless
theoretical debate wearying. As long as it continuous then the
newsgroup will be useless to newer licensees, like my self, who would
like to get some "patient council to the beginner" from those of you who
have been there and done that. Before I have to go there and do that
would be soon enough.
--
Tom Horne, W3TDH

Tom

Get together with some friends and have them drive out and assess your
signal under real life conditions. Make a day of it and all get together
in the evening for a social gathering and to compare notes. You really
need to know whether it works okay or not, not what the 'S' meter is
reading.

Mike G0ULI

Mike
I already own the J pole I mentioned and an Isopole for two meters. I
expect to have a third two meter omni to cover APRS, Packet, and voice. I
can see me throwing up each of these antennas in turn in a shopping center
parking lot on a Saturday night when all the cars are gone and doing some
measurements. I cannot see me rigging each in turn to the eve brackets on
my house while my victims, I er mean buddies or at least they would be at
first, cool their collective heals waiting for each successive test. Then
there is the possibility that we may need to pre-install some sort of dual
or mono band antenna at each of thirty plus fire stations and you can see
why we might want to know which of the designs we can build or buy will
put out the strongest signal. If I test at my home I will know which
antenna works here but I'm unlikely to be called on to provide emergency
communications from my home. I'd like to find out in as objective way as
possible which antenna has the best chance in terms of power out to get
the signal through in conditions that cannot be known in advance.
--
Tom Horne
--
Tom

Hi Tom

That's a very fair comment under the circumstances. That sounds like a
pretty big project you are planning. Setting up an antenna farm in a big
field or car park and plotting the antenna patterns with a field strength
meter, or hooking up an Icom scanner to a PC and recording the results seem
like the best suggestions so far.

Do remember that each site where you eventually install the antennas will
have it's own characteristics. One design may not be suitable for
everywhere. I personally have had very good results with a semi commercial
5/8 over 5/8 co-linear design with 6 x 24" horizontal radials at the base.
The antenna is cut and tuned for the 2 metre band, but also works well on 70
Cm. Range fully quietening around 40 miles on only 5W on 2m across flat
terrain with the base of the antenna 20 feet above ground. This is the most
effective design I have come across for omni-directional working. The whole
thing is built in a seamless fibre glass tube with the radials screwed into
a ring bonded at the base of the antenna.

Good luck with the project

Mike G0ULI