Thread: Antenna's
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Old January 5th 04, 06:14 AM
Rich B.
 
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Does the factor 234 equal full wave or partial? 3.3" sounds a might small
for 850 mhz


"L." wrote in message
...

"Dxluver" wrote in message
...
try a homemade vertical di-pole with one element for each band you
want to receive soldered to some good coax. For protection from the

weather
you can seal it in a suitable length of PVC pipe with endcaps.

For the bands you mention above, your elements would be: 17", 6", and

3.3".
One of each soldered to the center conductor and another of each

soldered
to
the shielding. This is not a transmitting antenna so no impedance

matching
mechanism is necessary and the coax can run down alongside the lower

half
of
the di-pole.

To calculate other lengths: FEET=234/MHz (i.e. 17'=234/160.000).

Hey Frank,
That is interesting and I know of the thinking behind it. Have you or

someone
you know (maybe someone in this group) ever run an antenna like that and

what
are/were the results. {?}

This might sound silly, but you wouldn't need a switch box would you to

switch
to each 'antenna.'?? You mean you could use this 'one' antenna and just

run it
straight to your scanner and as you searched different parts of the

spectrum
the cut antenna would automatically work for the part/areas you were

scanning?

Thanks for any reply by anyone. :-)

**I know in SWL you'd have to use a switchbox for a setup like that.


His idea is similar to the antennas that RS and maybe others sold. The

ones
with "3" vertical radials one for VHF low, one for VHF Hi and one for

UHF -
3 distinctly different length vertical elements - all mounted to a center
plate and connected to a SO239 with ground radials to boot. I made one

like
it once out of a block of wood, 3 clothes hangers and 4 curtain rods - to
work in a pinch. I used 50 ohm coax. It worked quite well when made to
center of the bands they were to receive. No switch box needed. L.