OK, John, this is from my experience. Have been flying these things in the 160
for
over 20 years.
A good source for balloons is a local Army/Navy surplus store. They generally
carry weather balloons normally meant to be inflated to a diameter of 6'. As
a rule, I have found something on the order of 3.5' to be the proper diameter
of the inflated balloon to give it proper lifting strength.
You don't need #14 wire. If you can find some hard drawn enamel ( used to
rebuild
motors ) #18 will do just fine, and reduce the size of the weight you have to
lift.
On the matter of weight, if you have two supports in the general neighborhood of
where you will be flying the beast, run a piece of light weight line between the
two. This can then serve as the bottom of the thing, and you can use any size
wire
you wish from the ground to the baloon, and then your lightweight stuff. This
also
gives you a little leeway in case of a wind. My line is 90' high, and by simple
rules of aerodynamics, cannot blow over more than 45 degrees plus the drag
coefficent of the baloon.
I have found anything over 1/2 wavelength to not justify the effort. Have flown
them from 240' to over 700'. Besides, feeding a 1/2 is simplicity at its best.
Just use a paralle LC circuit. and tap the coil for a 1:1 match. By the way,
while
you are attaching the antenna to the tuner, it's a good idea to clip a long
test
lead to the antenna and ground. You'd be amazed at how much build up you get.
Nothing serious, but enough to wish you had grounded the sucker before you
touched
the end of the wire.
Keep in mind you have an antenna 250' long of so....If you can reach a power
line
with the antenna, don't do it. I have about 6 acres here, with 100 foot oaks
blocking the way to the power lines, and I still use the rule.
As a general rule, you can refill the baloon about 6 times from a single tank of
gas. You mention hellium, but hydrogen, is cheaper and has a much higher lifting
ability. Incidentally, tie a string from the baloon about 2 feet long and make
a little loop in the top of the wire and tie the string to that. DO NOT attach
the antenna directly to the baloon. It's a good idea not to smoke around the
baloon if you use hydrogen. In my opinion, you're getting ripped off on the
price. My supplier charges $35 for a full tank. And you can make a fitting to go
on the top of the tank from common hardware items. You don't need a pressure
regulator.
During the day, I will either leave the thing up, or if it's sorta windy, will
pull it down by the fishing line I attach to the top, and teater it off. If you
overinflate slightly to begin with, it will not be necessary to recharge the
thing. Helium by the way, will escape through the rubber of the baloon. As a
matter of fact, you are constantly losing it from the tank also. It has the
ability to squirm through stainless steel. Of course, that takes a little
longer.
If it's quiet, you can use it for receive also, but you still need Bevs., ect.
Also, if you will use a coax switch and ground the coax during receive, you will
be amazed. What I do is use a small low voltage relay to trigger the coax relay.
The small relay is controlled by the amp relay in my Omni, and effectively, I
key
the amp by keying the small relay, which sends 12V to the coax relay. I use the
other side of the relay to close the amp. In effect, I key the amp through 250 "
or so of Romex. This way, if the antenna relay, fails to actuate, the amp will
not
key, and the SWR protection circuits of the Omni, will shut it down.
OK, this is too long. Enjoy, and let me assure you nobody messes with that
antenna
with a Titan tied to it, and believe me, they have tried.
Best
ED
-------------------------------------
Name: Ed Sleight
E-mail: k4sb@avana.net
Time: 10:10:43 PM
"May you be in heaven 10 minutes before the devil knows you're dead"
-------------------------------------
>From neader@centuryinter.net (Scott Neader) Wed Aug 14 04:10:07 1996
From: neader@centuryinter.net (Scott Neader) (Scott Neader)
Subject: New site for Near-Field Analysis Software
Message-ID: <v02140b10ae36e85ea266@[206.65.185.11]>
The ftp site will been shut down soon, and K6STI has asked me to place the
file onto my site, which I have done.
NF.ZIP can now be found at http://www.QTH.com/ka9fox
Click on "The Contest / DX Library", then click on "Software"
73 - Scott KA9FOX
----------------------------------------------------------------------------
INTERNET SOLUTIONS - Affordable web page design and storage
Scott Neader (608)788-1234 / FAX (608)787-0100 / neader@centuryinter.net
Internet Solutions web: http://www.QTH.com/is Ham web: http://www.QTH.com
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