Hi Bob,
No problem on not being specific as the whole idea of putting
a message on the newsgroup was to add to the discussion. As they say in
training sessions, no questions are silly questions !! Any yes your right
we do fly some distance away, and coms then would be useful for safety.

I'll have to look out a design for a 5/8 using tubing !

Cheers, Malcolm...


"Bob Bob" wrote in message
...
Hi Malcolm

The 1/4 will easily cover the 500khz at that frequency.

I'd also suspect that even if you went to (say) a colinear antenna to
keep the radition lower to the ground, there would be more than enough
signal going "upwards" to the aircraft.I guess you cant actually measure
signal strength of received aircraft? You may even find that (say) the
lower angle of a 5/8 whip actually helps when the aircraft are some
distance away...

I think the most important factor for comms with the winch site is to
get both antennas as high as possible and if using a long coax run make
it low loss. You have already indicated problems in this area. Possibly
the winch install needs to be easy to knock down without damage?

Apologies for not being specific..

Cheers Bob VK2YQA

Malcolm Austin wrote:
Hi,
I have an interesting problem which I'd like to put to the
newsgroup
for idea's. Our club (gliding by the way) uses just a few frequencies
to
transmit (AM) and receive on.

The main freq' is 129.975, but we go down to 129.900 and up to 130.400.

We need some new antenna's but I'm wondering what would be the best.
Currently we use a quarter wave set for 129.975, but this is I'm afraid
just
cut to a length (the lads are pilot's and not Ham's !!)

The quarter wave of course is good in one respect that we are all
hopefully
up in the air so the high angle of radiation helps. It would be good
though
to improve the signal to our winch which is just 950 metres away (3100
feet
for some!) but over the hill so to speak, so not line of sight. We
struggle
at times on our max 1 watt output to hear each other.

I'm wondering what I can build that will help this low angle but leave
the
high angle still there. Also it would help, to have the VSWR band width
with us and not against us on all the frequencies. For the winch we
have
limited height available on the top due to hangerage restrictions. If I
build something big and solid, some one is sure to forget and rip it off
going into the MT hanger. Our base end is a good old English double
decker
bus, so we have a good ali ground plane some 20 feet in the air. None
directional capabilities are of course required as we fly 360 degrees
around
the club.

Any thoughts out there?

Many thanks,

Malcolm - Radio Ham and Glider pilot.