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.

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.

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.

"Malcolm Austin" wrote in message
...
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.

Malcom

I'd suggest that the antenna at the winch can be made more directional
without increasing its height. But, you've probably thought of that. It
would seem to be a good place to try a simple, small Yagi at the winch.

Jerry

Hi Jerry,
yes had thought of going directional, but have some small
problem. Him up stairs, keeps changing the wind so we have to move the
winch about the field. Some times this can be by 180 degrees ! So we are
restricted to omni-directional...

Cheers, Malcolm...


"Jerry Martes" wrote in message
...

"Malcolm Austin" wrote in message
...
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.

Malcom

I'd suggest that the antenna at the winch can be made more directional
without increasing its height. But, you've probably thought of that. It
would seem to be a good place to try a simple, small Yagi at the winch.

Jerry

Malcom

It seems that you've got a problem on your hands. The base station must
cover the hemisphere and have good gain at or slightly below the horizon. I
suspect thats a very difficult pattern to produce with linear polarization.
A QHA (helical) antenna might be an interesting antenna to try. But, it
wouldnt be an easy antenna to develop and construct, like the J-pole or
discone.

Jerry






"Malcolm Austin" wrote in message
...
Hi Jerry,
yes had thought of going directional, but have some small
problem. Him up stairs, keeps changing the wind so we have to move the
winch about the field. Some times this can be by 180 degrees ! So we are
restricted to omni-directional...

Cheers, Malcolm...


"Jerry Martes" wrote in message
...

"Malcolm Austin" wrote in message
...
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.

Malcom

I'd suggest that the antenna at the winch can be made more directional
without increasing its height. But, you've probably thought of that.
It
would seem to be a good place to try a simple, small Yagi at the winch.

Jerry

On Mon, 12 Jul 2004 22:36:47 GMT, "Malcolm Austin"
wrote:

Hi Jerry,
yes had thought of going directional, but have some small
problem. Him up stairs, keeps changing the wind so we have to move the
winch about the field. Some times this can be by 180 degrees ! So we are
restricted to omni-directional...

How about a discone? They cover a very wide range of frequencies and
are *relatively inexpensive. Probably on the order of $50 or so. The
simple Radio Shack model covers from about the FM broadcast band which
is well below the aviation band to over 440 MHz and are
omni-directional. There is a null directly overhead, but they seem to
do well. Otherwise I'd go with a ground plane and use a very large
diameter vertical element compared tot he regular size.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com


Cheers, Malcolm...

Hi Roger,
I'm beginning to think that some 2" tubing would be good at
the control end and half that at the winch (receive is the main interest)
would be the best way forward. I'm going to make some thing up and give it
a go.

Cheers, Malcolm...

"Roger Halstead" wrote in message
...
On Mon, 12 Jul 2004 22:36:47 GMT, "Malcolm Austin"
wrote:

Hi Jerry,
yes had thought of going directional, but have some small
problem. Him up stairs, keeps changing the wind so we have to move the
winch about the field. Some times this can be by 180 degrees ! So we are
restricted to omni-directional...

How about a discone? They cover a very wide range of frequencies and
are *relatively inexpensive. Probably on the order of $50 or so. The
simple Radio Shack model covers from about the FM broadcast band which
is well below the aviation band to over 440 MHz and are
omni-directional. There is a null directly overhead, but they seem to
do well. Otherwise I'd go with a ground plane and use a very large
diameter vertical element compared tot he regular size.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com


Cheers, Malcolm...