Another choice is to buy a cylinder, which is what most consumer/retail
users now do in the US. The 150 ft^3 cylinders were going for around
$180 empty pre covid. The specific cylinder can be refilled or
exchanged which has the advantage of free pressure recertification (at
least at my welding supplier).
DON'T buy "private" used cylinders (w/o documentation) as they are often
pirated rentals and won't be refilled or might have residual really
deadly gas. eg silane SiH4
Grant KZ1W
On 11/8/2021 15:02, Adrian wrote:
Here, for full size 90cm - 1m balloons it works out around $20 au helium
per balloon, plus $2 balloon plus $5-10 average line loss.
So a night session is around $30 au in costs on average, and only when
conditions are right, otherwise you are wasting your time and $.
The bigger the industrial bottle you can purchase the better the deal.
Also you can negotiate price with the supplier, I cut my original
offer price nearly in half as well is 25% off my rental. Recommended
retail compared to a trade customer pricing has big pricing difference.
In the USA you should be able to do it for $20 or less per balloon. Also
using too big a balloon is wasting helium $ and increasing line break risk.
I use difference inflation levels for each band 630m biggest to 80m
smallest. If I re-use balloons, i only use them on 80m , which is the
smaller inflation.
A bigger balloon gets hit harder and creates much more line stress with
sudden gusts. The advantage of using 3/4 w setups is if the break is at the
1/4w point (trees house etc) the impedance change to the amp is not so
dramatic and the LDMOS amp in low survives the event on swr trip.
Watching the swr real-time on the SPE, and have a finger on the halt
button has saved gear here. A sudden wind change and a 2nd story gutter
contact can just
blow the line at the contact point during TX, and its start again, but
the amp remains good.
As the line changes angle the swr changes with it, and with experience
trouble can be avoided.
The lift force should just be in excess of the total line weight, less
than 2:1.
vk4tux
On 9/11/21 08:32, Mark - N5OT wrote:
> we used a 4-5' - "rubber" balloon. (could've been latex or
something similar)
So did I. A 4 foot diameter balloon has 33-ish cubic feet of volume.
Looks like Helium is running about $2 a cubic foot = $66 per use?
Gad. Too pricey for N5OT.
73 - Mark
On 11/8/2021 4:21 PM, Adrian wrote:
Also the disposable party balloon bottles are a waste of $ and would
only inflate 2 to 3 of the balloons here.
Industrial gas supply is required to make it viable.
"
ABN 95 000 029 729
Riverside Corporate Park
10 Julius Ave, North Ryde NSW 2113
Tel: 131 262 www.boc.com
Email: contact@boc.com
2nd June 2021
Dear Adrian Fewster,
BOC special offer on compressed gas for Adrian Fewster.
Thank you for your enquiry regarding the supply of gases and
equipment from BOC Limited. Our customers
are assured of BOC's genuine commitment to providing premium gas
products and services in addition to
ongoing technical support, and the convenience of our large national
distribution network.
Pricing for products which are purchased by you but which are not
listed in the special offer pricing table
below will be charged at BOC's standard or list prices for each such
individual product as varied from time
to time unless otherwise agreed. The gas pricing for the products
listed in the special offer pricing table
below will be varied in proportion to changes in BOC's standard
prices for each individual product and the
rental pricing will vary in line with BOC's standard charges unless
otherwise agreed. This does not apply to
prices for LPG, Refrigerant, Helium and Acetylene products which will
vary in line with Supplier increases as
they are incurred.
All prices below are GST exclusive. Price may vary if purchased from
a different BOC Gas & Gear or Gas
Agent.
Gas CodeDescriptionCylinder
Volume
Annual
Quantity
Delivered
Price**
Rental (per
day)##
124GBALLOON GAS G SIZE7.1m31$398.31$0.6822
For refrigerant products a refrigerant reclaim and fluoro activity
levy of $2.38/kg also applies.
** Where a standard local delivery option is available
## Rental Pricing is described as Service Charges in BOC's General
Terms and Conditions of Supply
Rental Pricing
Cylinder CodeRental (per day)
'G' Size$0.6822
You may accept the special offer pricing above in the manner set out
in the last paragraph of this letter. By
accepting the special offer pricing above, you warrant that you do
not have a binding exclusive supply
arrangement with another supplier for any or all of the products
listed in the special offer pricing table
above (or for products substantially similar to those listed)
applicable to your site(s) where the products are
to be used.
The Agreement so formed between BOC and you for the supply of the
products listed in the special offer
pricing table above will consist of the terms and conditions set out
in this special offer pricing letter
together with the BOC General Terms and Conditions of Supply. (as
amended from time to time) (accessible
from our website (www.boc.com.au)).
Under this Agreement we will supply and you will purchase all of your
requirements for the products
covered by this Agreement. This Agreement will commence on the date
of formal acceptance and continues
until you or we terminate it by giving a minimum of 6 (six) months'
notice expiring at the end of the
minimum period of 1year(s) or by either party giving a minimum of 1
(one) months' notice after the expiry
of the minimum period, or until it is terminated under the BOC
General Terms and Conditions of Supply.
At BOC we believe that our business is here to help your business so
if you have any queries please feel
free to get in touch with me at jamie-lee.palelei@boc.com.
This offer will be loaded to your customer account within two
business days. "
vk4tux
On 9/11/21 07:54, W7TMT - Patrick wrote:
Regarding the helium…
Be advised the gas used by the party stores these days is almost
always a mixture and not pure helium. That’s means considerably less
lift. You’ll likely need to source the good stuff from a industrial
gas supplier.
W7TMT
________________________________
From: Topband<topband-bounces+w7tmt=outlook.com@contesting.com> on
behalf of Mark - N5OT<r-emails@n5ot.com>
Sent: Monday, November 8, 2021 1:17:53 PM
To: TopBand List<topband@contesting.com>
Subject: Re: Topband: Balloon Supported Vertical
Been There Done That
You might want to figure the weight of what you have to lift. One would
think it was, like, duh, you make a wire vertical and fill a balloon
full of helium and ... but it turns out you need to be careful about
the
weight of the wire and insulators and you need to project how much
helium you can use and how much lift you will need and ... all that.
Just saying all that because the last thing you want to find out is,
after you've got it all together, you just can't get it up in the air.
I seem to recall I needed more like a 3 or 4 foot balloon to lift mine.
And be careful of the sticker shock on the gas. I thought it was a lot
of money 20 years ago. Rumor has it, it has not gone down in price.
The first one worked well until I had a bad wind.
The second one had some kind of corona arc off the top of the wire
which
popped the (relatively expensive) balloon after only a couple
minutes of
testing it out. Or something. It popped on a clear calm day but under
Full Power.
Anyway, that wrecked my day. I decided it wasn't fun any more and have
been using more conventional 160 meter verticals since.
I think we wrote it up in the NCJ but don't remember and have slept
since then.
Oh sorry, you asked where to get the balloons. I think I got mine from
a party supply store. It was not mylar.
Note - Googling reminds me of these facts:
Helium can lift 1 gram per litre.
A balloon 2 feet in diameter will contain 118 litres of helium.
That will lift 118 grams of antenna, = 4.1 ounces.
132 feet of bare #18 solid copper wire weighs 10.4 ounces.
A 2 foot balloon filled with helium will not lift a 160 vertical
made of
#18 wire, not to mention any extra line or insulators, etc.
But a 4 foot balloon will lift a little over 2 pounds.
Now I'm having nightmares again.
73 - Mark N5OT
On 11/8/2021 2:48 PM, Dick Bingham wrote:
Greetings All
I want to try a balloon supported Vertical for 160.
Any advice on sources for balloons? Mylar material
and diameters up to 2-feet would be my choice.
73. Dick/w7wkr at CN97uj
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