[gareth]

"Michael Black" wrote in message
ample.org...

I vaguely recall reading about rules for antenna height near airports.

In Brit, not exceedng 50 feet within 1/2 mile of any runway, ISTR.

[Stephen Thomas Cole[_3_]]

Jeff wrote:
On 25/04/2015 05:32, gareth wrote:
"Michael Black" wrote in message
ample.org...

I vaguely recall reading about rules for antenna height near airports.

In Brit, not exceedng 50 feet within 1/2 mile of any runway, ISTR.



That clause hasn't been in the UK licence for about the last 30 years.

Jeff

Perhaps not, but is there not local authority/planning regs that restrict
mast and/or antenna height within x distance of airports? I'm sure I read
that a while back when researching putting my own mast up (didn't do it in
the end), I'm only about 2 miles from Rochester airport so it stuck in my
mind.

--
STC // M0TEY // twitter.com/ukradioamateur

[Edwin Johnson]

On 2015-04-24, Ian Jackson wrote:

See
http://www.allsopp.co.uk/

Those are pretty sophisticated balloons. Bet those are similar to the
aerostats the US uses around the Gulf of Mexico for surveillance purposes.
Those are tethered and go up thousands of feet and are marked on our
aeronautical charts. Prices must be high on those, out of the limits of the
average ham here. hi

73 ...Edwin, KD5ZLB
__________________________________________________ __________
"Once you have flown, you will walk the earth with your eyes
turned skyward, for there you have been, there you long to
return."-da Vinci http://www.kd5zlb.org

[highlandhamFrank]

On 24/04/15 02:43, Allodoxaphobia wrote:
On Thu, 23 Apr 2015 11:56:18 -0700, Oregonian Haruspex wrote:

How about a tethered helium balloon instead? This way you don't have
to worry about powering the thing. Bell wire will handle 100 watts all
day without turning into smoke.

Then (for a full sized Top Band vertical) you'd better be
prepared for some VERY SERIOUS static electricity issues.
(And, it won't be vertical. It'll be a "slooper", I believe.)

One Field Day we threw up a cross-valley long wire (running horizontal,
of course) and, after the violent static display made itself known
inside the Field Day trailer, several fellas got knocked on their asses
trying to get it disconnected and away from all the other gear and
antennas around the site. That sucker was approx. 2200 feet long.
(Could've gotten 100 pts for "Natural Power", I s'pose...)

The Colorado Rockies: Low humidity - steady breeze -- sure was exciting
for awhile!

Jonesy

================================
To the matching box (tuner if you like) attached to my twin-feeder
dipole I have added a 47Kohm carbon resistor from 1 of the feeder
connections to chassis (ground) to avoid static build-up ,since the
attached inductor inside the box is not grounded.
Of course this does NOT protect against a lightning strike .
The 47 KOhm or higher resistor does NOT affect the antenna matching.

Before adding the resistor I had a flashover (due to static build-up)to
the primary inductor connected to the transceiver input. Fortunately
there was no transceiver damage ,but the solar panels /wind generator
13.8V set voltage controller was knocked-out.
Since adding the resistor ,many years ago, no more problems.

The above shows that (for a home brew matching box of the E-Zee type) it
is important that the centre of the inductor connected to the twin
feeder is grounded , alternatively a carbon resistor in the 47-100 kohm
range connected to one of the feeder connections, is grounded.

Frank , GM0CSZ / KN6WH in IO87AT

[bilou]

"Ian Jackson" wrote in message
...
In message , Edwin Johnson
writes
On 2015-04-23, Oregonian Haruspex wrote:
On 2015-04-18 08:38:31 +0000, gareth said:

How about a tethered helium balloon instead? This way you don't have
to worry about powering the thing. Bell wire will handle 100 watts all
day without turning into smoke.

This sounds like a neat experiment, which one of our members tried on
field
day. There are several problems in the electrical side of things, but more
importantly on the physical side. As you rise in altitude the wind speed
will increase, generally speaking, and perhaps change directions. If the
day
is completely calm especialy above the tree line, say 100-200ft, then the
balloon will remain straight up. But launching a balloon in a 10mph wind,
which becomes 15-20mph above the tree line, leads to interesting
developments with the tether wire/cord definitely sloping and perhaps
being
pushed into surrounding objects such as trees, power lines (eh gads!)
which
can cause it to break or other things. So you need plenty of space with
few
impediments for the balloon to catch on as it ascends. You certainly can't
predict a perfectly calm day, so this can be an unpredictable venture. ha

See
http://www.allsopp.co.uk/
Is there any practical way to put back the Helium in the bottle in case of
success
or not too complete failure ?
This will surely lower the cost of experimentation.

[[email protected]]

Stephen Thomas Cole wrote:
Jeff wrote:
On 25/04/2015 05:32, gareth wrote:
"Michael Black" wrote in message
ample.org...

I vaguely recall reading about rules for antenna height near airports.

In Brit, not exceedng 50 feet within 1/2 mile of any runway, ISTR.



That clause hasn't been in the UK licence for about the last 30 years.

Jeff

Perhaps not, but is there not local authority/planning regs that restrict
mast and/or antenna height within x distance of airports? I'm sure I read
that a while back when researching putting my own mast up (didn't do it in
the end), I'm only about 2 miles from Rochester airport so it stuck in my
mind.

In the UK it is regulated by the CAA.

If you ever intend to do something like this, I would highly suggest
going through all the regulations first.

In the US, the FAA has regulations about structures near an airport
with maximum heights that depend on distance and separate regulations
about balloons and kites near airports.

I am sure the CAA regs, and most other countries as well, are similar
to the FAA regs.



--
Jim Pennino

[[email protected]]

Edwin Johnson wrote:
On 2015-04-24, Ian Jackson wrote:

See
http://www.allsopp.co.uk/

Those are pretty sophisticated balloons. Bet those are similar to the
aerostats the US uses around the Gulf of Mexico for surveillance purposes.
Those are tethered and go up thousands of feet and are marked on our
aeronautical charts. Prices must be high on those, out of the limits of the
average ham here. hi

73 ...Edwin, KD5ZLB
__________________________________________________ __________
"Once you have flown, you will walk the earth with your eyes
turned skyward, for there you have been, there you long to
return."-da Vinci http://www.kd5zlb.org

What you want is something that is a combination of a kite and a balloon
and is more kite than balloon to avoid having to have a lot of helium.

As it need not be man rated, you could make it from tissue, light wood,
with party balloon fillers.

Or if you are feeling adventurous, use hydrogen making sure there are
no sparks at the end of your antenna.


--
Jim Pennino

[Steve]

On Sat, 25 Apr 2015 16:42:02 +0200, bilou wrote:

"Ian Jackson" wrote in message
...
In message , Edwin Johnson
writes
On 2015-04-23, Oregonian Haruspex wrote:
On 2015-04-18 08:38:31 +0000, gareth said:

How about a tethered helium balloon instead? This way you don't have
to worry about powering the thing. Bell wire will handle 100 watts
all day without turning into smoke.

This sounds like a neat experiment, which one of our members tried on
field day. There are several problems in the electrical side of things,
but more importantly on the physical side. As you rise in altitude the
wind speed will increase, generally speaking, and perhaps change
directions. If the day is completely calm especialy above the tree
line, say 100-200ft, then the balloon will remain straight up. But
launching a balloon in a 10mph wind, which becomes 15-20mph above the
tree line, leads to interesting developments with the tether wire/cord
definitely sloping and perhaps being pushed into surrounding objects
such as trees, power lines (eh gads!) which can cause it to break or
other things. So you need plenty of space with few impediments for the
balloon to catch on as it ascends. You certainly can't predict a
perfectly calm day, so this can be an unpredictable venture. ha

See http://www.allsopp.co.uk/
Is there any practical way to put back the Helium in the bottle in case
of success
or not too complete failure ?
This will surely lower the cost of experimentation.

The cost of Helium will continue to rise. Once used, it is effectively
gone for ever as it will leave planet Earth to mix with the rest of the
Helium in space. What we have now is from reserves that come from nuclear
reactions within our planet, and that is all we have got!

Perhaps it's time for us to be less flippant over using this
irreplaceable wonder element!

[Jeff Liebermann[_2_]]

On Sat, 25 Apr 2015 14:17:46 +0000 (UTC), Edwin Johnson
wrote:

On 2015-04-24, Ian Jackson wrote:

See
http://www.allsopp.co.uk/

Those are pretty sophisticated balloons. Bet those are similar to the
aerostats the US uses around the Gulf of Mexico for surveillance purposes.
Those are tethered and go up thousands of feet and are marked on our
aeronautical charts. Prices must be high on those, out of the limits of the
average ham here. hi

73 ...Edwin, KD5ZLB

Yeah, but not too horrible. See price list at:
http://www.allsopp.co.uk/index.php?mod=page&id_pag=35
My guess(tm) on the weight of a 1/4 wave 160 meter monopole was 464
grams without the weight of the balloon, insulators, and whatever else
might be needed. Looking at the chart, I could get a "Skyhook" model,
that would lift 800 grams with no wind, for $760 excluding VAT, duty,
and shipping. You decide if having the loudest signal on 160 meters
is worth the expense.


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

[Jeff Liebermann[_2_]]

On Mon, 20 Apr 2015 20:36:48 +0100, Ian Jackson
wrote:
(...)

Today, we had Chen Dubin, owner of Santa Cruz Drones, gave a
presentation and a demonstration of his drones at the FLUG (Felton
Linux Users Group) meeting:
http://www.santacruzdrones.net/#content_area
Of course, I mentioned the idea of using a tethered drone aerostat to
support a wire antenna and asked how long the motors would last before
overheating. His drones have rather large motors, which he says would
last for days. He also mentioned that the military is already using
such tethered drones to hoist antennas. For example:
http://www.skysapience.com
http://www.droneaviationcorp.com/tethered-drone.html
https://www.google.com/search?q=tethered+drone&oe=utf-8
https://www.google.com/search?q=tethered+drones&tbm=isch

I also asked if he has tried any of his drones near the local AM
transmitter antennas (KSCO). It seems he lives nearby, hangs around
the station, and has not seen any problems. So, it should work at 160
meters. (The control links are usually 2.4GHz. Video is either 900
MHz or 5 GHz).

Since the main limitation of a tethered drone is weight lifting
ability, doubling the wire length and hoisting a 1/2 wave antenna is
easy. A half wave antenna does not need a ground plane, and might
work better than a 1/4 wave. End fed 1/2 wave antennas:
http://www.aa5tb.com/efha.html
http://www.vk2zay.net/article/115
http://pages.suddenlink.net/wa5bdu/efhw.htm
http://www.w8ji.com/2end-fed_1_2_wave_matching_system_end%20feed.htm



Drivel:
Kite and balloon lifting antennas for 160 meters:
http://www.qsl.net/g4vgo/
http://www.qsl.net/g4vgo/Kites.htm


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558