I know a way we can settle this.
Andy, can we put a UV detector on the next balloon launch?
On 3/23/2019 11:37 AM, Ravi Patrick Ratnala via BVARC wrote:
I think there’s a pretty big difference. Attenuation occurs at
varying rates depending on the nature of the atmosphere the UV is
traveling through at the time, but it does occur all the way to the
ground; all else being equal, shorter wavelengths are absorbed higher
up; long-wavelength UVA makes it pretty much all the way to MSL.
https://www.sciencedirect.com/science/article/pii/S1011134496000188
For the 200-300 nm range Nizar mentioned, my guess is that the
attenuation between 100k’ and MSL is ~95% or more. That’s just a
hunch though.
But I’m certain that the increased UV damages the balloon on a
microscopic level more at altitude than at MSL. Whether it plays a
measurable role in the time-to-burst, who knows. Sounds like a good
experiment for a future flight (though I’ve no idea how you’d control
it!).
73 de N5OL
Sent from my iPhone
On Mar 22, 2019, at 8:29 PM, Jonathan Guthrie via BVARC
<[email protected] <mailto:[email protected]>> wrote:
I don't believe there is a significant difference in UV radiation
between 100,000 feet or so and the ground. Plastics at ground level
that are intended to be exposed to direct sunlight for long periods
of time routinely have UV protection added to them.
On 3/22/19 9:56 AM, NIzar Mullani via BVARC wrote:
Ravi,
Glad you mentioned UV radiation as a heating source. I had not
thought about this before. As we get into rarefied air, the very
short wavelength UV light in the 200 to 300 nm range could also
become very damaging to the superficial layers of material.
I wonder if anyone has looked into how this extra short UV radiation
effects balloon materials, and, whether it plays a role in the
longevity of balloon material!
Nizar
*From:*BVARC [mailto:[email protected]] *On Behalf Of *Ravi
Patrick Ratnala via BVARC
*Sent:* Thursday, March 21, 2019 5:11 PM
*To:* BRAZOS VALLEY AMATEUR RADIO CLUB
*Cc:* Ravi Patrick Ratnala;
[email protected]; [email protected];
[email protected]; john Parmalee; [email protected];
[email protected]
*Subject:* Re: [BVARC] Especially for those that won’t be able to
make it to the Houston HamFest this weekend . PLEASE REPOST
Sounds like y'all are talking about moving through the tropopause;
from the troposphere, and upward through the stratosphere.
Temperature decreases (generally) with altitude in the troposphere,
because this region is ruled by thermal heating of the ground (and
associated boundary layer), convection, and adibatic expansion.
Once you get into the stratosphere, temperature increases with
altitude due to heating by UV radiation. (Obviously this is a short
form description.)
73, Ravi
On 3/21/2019 1:16 PM, Bruce via BVARC wrote:
i would have thought as the balloon gets higher with thinner air
that the temperature would get colder. you say it goes up.
interesting. i may need to take a look at that. neat experiment.
73...bruce
Sent from my iPhone
On Mar 21, 2019, at 1:10 PM, john Parmalee via BVARC
<[email protected] <mailto:[email protected]>> wrote:
*Especially for those that won’t be able to make it to the
Houston HamFest this weekend.*
*Two Balloon launches with ham gear on board. You can participate. *
*Live video of both launches **https://zoom.us/i/2815436502*
*9:30 AM BLT-51 will launch*
*You can track with **http://APRS.fi <http://aprs.fi/>**search
**the call W5ACM-10. *
*You can Google APRS to find the site.*
*BLT-51 will be a floater, designed to be tracked via APRS and
glide across the country, and hopefully even further. The last
one went to Florida in about six hours.*
*Around 1:00 PM another launch BLT-52*
*BLT-52 is a “popper.” **Designed to go up as high as possible
and burst, also to be tracked via APRS. Last August a popper
flew to nearly 100,000 feet. “To the edge of space.”*
*W5ACM Cross-band FM repeater will be in board with with *
*Input on 147.435 MHz **ß**-----**à**Output on 446.550 MHz no
tone, open to all to work *
*A WB8ELK APRS Tracker on 144.390 MHz with the call W5ACM-11
will be on board.*
*You can track at **http://APRS.fi <http://aprs.fi/>**search for
W5ACM-11*
*On board also the AB5SS Smart Beeper**on 10 and 20M 14.318 &
28.322 mHz, the temperature in CW call sign and BL-52. Wach as
the balloon passes through 60,000 feet the Temperature to rise. *
*The video will also be recorded for later playback as well, and
depending on the size of the captures, they will either be in
the groups.io <http://groups.io> FILES area
**https://groups.io/g/Ham-Radio-Tech-Notes/files** , or my
website.K5WH.net <http://website.K5WH.net>*
.
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Talk it up! On the air about every event, every meeting, every net, every
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Radio,Radio,Radio We are a radio Club!
Talk it up! On the air about every event, every meeting, every net, every time,
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--
Jonathan Guthrie
ARS KA8KPN
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Talk it up! On the air about every event, every meeting, every net,
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Message delivered to [email protected]
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Talk it up! On the air about every event, every meeting, every net, every time,
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Message delivered to [email protected]
