Home |
Search |
Today's Posts |
#22
|
|||
|
|||
A Top Band 1/4 wave vertical?
On 4/23/2015 10:38 PM, Jeff Liebermann wrote:
On Thu, 23 Apr 2015 19:25:21 -0700, Jeff Liebermann wrote: On Thu, 23 Apr 2015 18:32:56 -0700, Jeff Liebermann wrote: Helium previously costs about $8/liter but is now running about $20/liter thanks to the helium shortage. That's $14,600 for 730 liters. Are you sure you want to do this? Hmmm... that can't be right. The problem is that I'm getting prices for helium that are all over the map. For example: http://www.reuters.com/article/2013/09/19/us-helium-shortage-analysis-idUSBRE98I0AN20130919 "... spot price of liquid helium has jumped to $25-$30 per liter from $8 last year." http://www.crainsnewyork.com/article/20140126/FINANCE/301269974/helium-shortage-deflates-party-city "prices have doubled since 2006, to $6.13 per-cubic meter, according to the latest figures from the U.S. Geological Survey." 1 cubic-meter = 1000 liters, so that is $0.00613/liter which seems rather low. http://minerals.usgs.gov/minerals/pubs/commodity/helium/mcs-2014-heliu.pdf "The estimated price range for private industry’s Grade-A gaseous helium was about $7.21 per cubic meter ($200 per thousand cubic feet), with some producers posting surcharges to this price. 1 cubic-meter = 1000 liters, so that is $0.00721/liter, which agrees with the previous article, mostly because the price came from the same source. Ok, let's try party helium: http://www.sfparty.com/products.php?product=Helium%3A-Balloon-Time-Disposable-Helium-Tank-Purchase $55 for 14.9 cubic-ft. 14.9 ft^3 = 422 liters $55 / 422 liters = $0.13/liter Does anyone have the real price of helium? Never mind. I see the problem. There's a big difference between medical grade helium used to cool MRI machines, and the helium sold at party stores for filling balloons. http://www.bbc.com/news/uk-19676639 The party store helium is recycled from the MRI gas and is mixed (i.e. diluted) with air. "The helium we use is not pure," he said. "It's recycled from the gas which is used in the medical industry, and mixed with air. We call it balloon gas rather than helium for that reason." Mythbusters found this out the hard way when they tried to lift a 3 year old with a large number of helium balloons. http://www.discovery.com/tv-shows/mythbusters/videos/balloon-girl-minimyth/ They needed over double the number of balloons needed to lift the kid mostly because they used party balloon gas instead of the pure stuff. That also explains the price difference. You are also confusing gaseous helium and liquid helium. Not much in common. -- Rick |
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Forum | |||
Which is better: 5/8 wave vertical or J pole? | Antenna | |||
20m 1/4 wave portable vertical | Antenna | |||
New program - 1/2-wave vertical | Antenna | |||
5/8 wave 6m vertical | Antenna | |||
1/4 wave vertical vs. loaded vertical | Antenna |