Date   
Re: Looking for groups that plan to launch at GPSL 2020

Michael Hojnowski
 

I fear that with the purchase of a new home (which needs 170 years worth of repairs) and the pandemic that we'll be staying home this year.  I hope to put together a payload and simulcast a launch to be there in spirit.

Mike / KD2EAT

On 4/28/2020 5:48 PM, Mark Conner N9XTN wrote:
I would like to assemble a list of those who are planning to launch a balloon at this year's GPSL in Omaha if we can have an in-person event.  My concern at the moment is that even if we are able to have an in-person GPSL this year, so many may have work or financial impacts that we don't have a sufficient group to make it worthwhile.

If you or your group are planning to attend GPSL this year and fly a balloon, please send your email address (one person per group that's flying) to n9xtn@....  

Also, if your group is a regular attendee and you know for sure you will *not* be coming if we have an in-person event, I'd like to know that also.  

73 de Mark N9XTN
GPSL 2020 coordinator


Re: Looking for groups that plan to launch at GPSL 2020

Michael
 

Remote. Plan on trying a floater. 

--Michael Willett

On Apr 28, 2020, at 11:02 PM, stan siems <ssiems@...> wrote:

I will be launching from home if I get every thing in time

Stan WB0EMJ

On 4/28/2020 5:33 PM, Zack Clobes W0ZC wrote:
Unable to attend in person.  Probably remote.


Zack Clobes, W0ZC
Project: Traveler
www.projecttraveler.org

Join us on Facebook for the latest information:



Project: Traveler is a research project of Custom Digital Services, LLC.

On Tue, Apr 28, 2020 at 4:48 PM Mark Conner N9XTN <mconner1@...> wrote:
I would like to assemble a list of those who are planning to launch a balloon at this year's GPSL in Omaha if we can have an in-person event.  My concern at the moment is that even if we are able to have an in-person GPSL this year, so many may have work or financial impacts that we don't have a sufficient group to make it worthwhile.

If you or your group are planning to attend GPSL this year and fly a balloon, please send your email address (one person per group that's flying) to n9xtn@....  

Also, if your group is a regular attendee and you know for sure you will *not* be coming if we have an in-person event, I'd like to know that also.  

73 de Mark N9XTN
GPSL 2020 coordinator

Re: Looking for groups that plan to launch at GPSL 2020

stan siems
 

I will be launching from home if I get every thing in time

Stan WB0EMJ

On 4/28/2020 5:33 PM, Zack Clobes W0ZC wrote:
Unable to attend in person.  Probably remote.


Zack Clobes, W0ZC
Project: Traveler
www.projecttraveler.org

Join us on Facebook for the latest information:



Project: Traveler is a research project of Custom Digital Services, LLC.

On Tue, Apr 28, 2020 at 4:48 PM Mark Conner N9XTN <mconner1@...> wrote:
I would like to assemble a list of those who are planning to launch a balloon at this year's GPSL in Omaha if we can have an in-person event.  My concern at the moment is that even if we are able to have an in-person GPSL this year, so many may have work or financial impacts that we don't have a sufficient group to make it worthwhile.

If you or your group are planning to attend GPSL this year and fly a balloon, please send your email address (one person per group that's flying) to n9xtn@....  

Also, if your group is a regular attendee and you know for sure you will *not* be coming if we have an in-person event, I'd like to know that also.  

73 de Mark N9XTN
GPSL 2020 coordinator

Re: Looking for groups that plan to launch at GPSL 2020

L. Paul Verhage KD4STH
 

I plan to attend in person if it is possible.


On Tue, Apr 28, 2020, 3:48 PM Mark Conner N9XTN <mconner1@...> wrote:
I would like to assemble a list of those who are planning to launch a balloon at this year's GPSL in Omaha if we can have an in-person event.  My concern at the moment is that even if we are able to have an in-person GPSL this year, so many may have work or financial impacts that we don't have a sufficient group to make it worthwhile.

If you or your group are planning to attend GPSL this year and fly a balloon, please send your email address (one person per group that's flying) to n9xtn@....  

Also, if your group is a regular attendee and you know for sure you will *not* be coming if we have an in-person event, I'd like to know that also.  

73 de Mark N9XTN
GPSL 2020 coordinator

Re: Looking for groups that plan to launch at GPSL 2020

Zack Clobes W0ZC
 

Unable to attend in person.  Probably remote.


Zack Clobes, W0ZC
Project: Traveler
www.projecttraveler.org

Join us on Facebook for the latest information:



Project: Traveler is a research project of Custom Digital Services, LLC.

On Tue, Apr 28, 2020 at 4:48 PM Mark Conner N9XTN <mconner1@...> wrote:
I would like to assemble a list of those who are planning to launch a balloon at this year's GPSL in Omaha if we can have an in-person event.  My concern at the moment is that even if we are able to have an in-person GPSL this year, so many may have work or financial impacts that we don't have a sufficient group to make it worthwhile.

If you or your group are planning to attend GPSL this year and fly a balloon, please send your email address (one person per group that's flying) to n9xtn@....  

Also, if your group is a regular attendee and you know for sure you will *not* be coming if we have an in-person event, I'd like to know that also.  

73 de Mark N9XTN
GPSL 2020 coordinator

Looking for groups that plan to launch at GPSL 2020

Mark Conner N9XTN
 

I would like to assemble a list of those who are planning to launch a balloon at this year's GPSL in Omaha if we can have an in-person event.  My concern at the moment is that even if we are able to have an in-person GPSL this year, so many may have work or financial impacts that we don't have a sufficient group to make it worthwhile.

If you or your group are planning to attend GPSL this year and fly a balloon, please send your email address (one person per group that's flying) to n9xtn@....  

Also, if your group is a regular attendee and you know for sure you will *not* be coming if we have an in-person event, I'd like to know that also.  

73 de Mark N9XTN
GPSL 2020 coordinator

Helium becomes more rare due to collapse of oil market

Jeff Ducklow
 

I thought this article on shrinking helium supplies might be of general interest to the group.  It is written by a professor of out of Durham University in the UK.  Here is the link:


https://theconversation.com/helium-supplies-at-risk-from-plunging-oil-prices-which-is-bad-news-for-our-coronavirus-effort-137106



Jeff Ducklow
Mayberry Galactic
N0NQN



Minor GPSL 2020 update

Mark Conner N9XTN
 

I checked with UNO on the status of their summer events.  At the moment, they have cancelled all campus events through June 30 (GPSL session at UNO is July 10).  The person I'm working with does not know when they will decide about July events.

I'm also aware that some may have difficulty traveling to GPSL this summer because of job situations.  That will also be factored into the in-person vs virtual decision - if we don't have a critical mass that can come in person and launch, it may not make sense to have it in person.  

73 de Mark N9XTN

Re: Payload Power Sources

Joe WB9SBD
 

DUH?!

I shouldn't be reading charts at like 3 AM. UG!

Thanks to all who answered my BrainFart!

Joe WB9SBD

The Original Rolling Ball Clock
Idle Tyme
Idle-Tyme.com
http://www.idle-tyme.com

On 3/27/2020 8:13 AM, BASE_DePauw wrote:
Joe,

The graph that you have shared has the horizontal axis in units of Ah (Ampere*hours) not in hours.  It is fine.

This means that all current draws are about 7.5 Amp hours with the smaller draws performing better than the large draw.

Howard, KC9QBN
BASE_DePauw



On Fri, Mar 27, 2020 at 9:02 AM Joe WB9SBD <nss@...> wrote:
I am very confused on a battery pack.

Say you have a pack that can run 1 amp of current draw for 10 hours.
One would think that if you only drew 0.5 amps that it should run for 20 hours or close to it true?

Now many of you old timers here will remember these awesome surplus packs that looked like this.

These things were OLD like 20 years old when we used them yet the power they could provide was incredible!
They were rated at 7500mah, incredible! Sadly this supply of "NOS" dried up and new packs were very prohibitive in prices. Easily ending up being like $100 bucks a flight!

But I found a source for Brand new ones, that would make it like $15 to $30 bucks a flight! YES!

But it's performance curve makes absolutely no sense to me!

This makes zero sense at all. I can draw 2 amps  or 0.25 amps and it changes the lasting run time by only like 15 minutes?

That doesn't make any sense!

Joe WB9SBD
--

The Original Rolling Ball Clock
Idle Tyme
Idle-Tyme.com
http://www.idle-tyme.com



--
Howard L. Brooks
Professor of Physics and Astronomy
241 Julian Science and Mathematics Center
DePauw University
2 E. Hanna Street
Greencastle, IN 46135
hlbrooks@...
Office: (765) 658-4653
FAX: (765) 658-4732

Re: Payload Power Sources

Hank Riley
 

Run time to a 24 volt cutoff because the effects on the capacity are clearer.

On the closeup graph view C1, C2 and C3 are the capacities for 2 amps, 1 amp, and .5 amp and lower.  That means at this cutoff voltage the ultimate capacity is reached at .5 amp and anything less for current drain does not lead to a higher A-H capacity.

C1(2)  is ~ 7.0   A-H  
C2(1)  is ~ 7.35  A-H       5.0% increase with respect to 2 amp capacity
C3(.5) is ~ 7.6   A-H       8.6% increase with respect to 2 amp capacity 

So runtime for 2 amps drain is 7/2 = 3.5 hours.

The other runtimes for 1 amp and .5 amp are 7.35 and 15.2 hours.

I've left off some of the units in the equation for 2 amps but as a check A-H divided by amps gives a result in hours so the units are dimensionally valid.


Inline image








Re: Payload Power Sources

Hank Riley
 

Joe,

You're just reading or interpreting the curves the wrong way.  The X or horizontal axis is A-H, not run time.

The greater the current, the lower the A-H time.  So in your example of .5 amp versus 1 amp, the .5 amp run time will be a little over twice the hours.  And to continue, the .25 amp run time will be a little over twice what the .5 amp run time was.

I'll do the actual numbers in next email.

Hank
____________________________________________________________


On Friday, March 27, 2020, 09:02:24 AM EDT, Joe WB9SBD <nss@...> wrote:

I am very confused on a battery pack.

Say you have a pack that can run 1 amp of current draw for 10 hours.
One would think that if you only drew 0.5 amps that it should run for 20 hours or close to it true?


Re: Payload Power Sources

David Akerman
 

The discharge capacity in Ah changes a little, due to internal I2R losses, so you get a bit more Ah from lower currents vs higher currents.  That's also why the voltage is a bit lower.  It's not showing you the run time directly - you need to divide Ah by A to get h, so your 0.25A load will run for more than 8 times the 2A load will.


On Fri, 27 Mar 2020 at 13:02, Joe WB9SBD <nss@...> wrote:
I am very confused on a battery pack.

Say you have a pack that can run 1 amp of current draw for 10 hours.
One would think that if you only drew 0.5 amps that it should run for 20 hours or close to it true?

Now many of you old timers here will remember these awesome surplus packs that looked like this.

These things were OLD like 20 years old when we used them yet the power they could provide was incredible!
They were rated at 7500mah, incredible! Sadly this supply of "NOS" dried up and new packs were very prohibitive in prices. Easily ending up being like $100 bucks a flight!

But I found a source for Brand new ones, that would make it like $15 to $30 bucks a flight! YES!

But it's performance curve makes absolutely no sense to me!

This makes zero sense at all. I can draw 2 amps  or 0.25 amps and it changes the lasting run time by only like 15 minutes?

That doesn't make any sense!

Joe WB9SBD
--

The Original Rolling Ball Clock
Idle Tyme
Idle-Tyme.com
http://www.idle-tyme.com

Re: Payload Power Sources

BASE_DePauw
 

Joe,

The graph that you have shared has the horizontal axis in units of Ah (Ampere*hours) not in hours.  It is fine.

This means that all current draws are about 7.5 Amp hours with the smaller draws performing better than the large draw.

Howard, KC9QBN
BASE_DePauw



On Fri, Mar 27, 2020 at 9:02 AM Joe WB9SBD <nss@...> wrote:
I am very confused on a battery pack.

Say you have a pack that can run 1 amp of current draw for 10 hours.
One would think that if you only drew 0.5 amps that it should run for 20 hours or close to it true?

Now many of you old timers here will remember these awesome surplus packs that looked like this.

These things were OLD like 20 years old when we used them yet the power they could provide was incredible!
They were rated at 7500mah, incredible! Sadly this supply of "NOS" dried up and new packs were very prohibitive in prices. Easily ending up being like $100 bucks a flight!

But I found a source for Brand new ones, that would make it like $15 to $30 bucks a flight! YES!

But it's performance curve makes absolutely no sense to me!

This makes zero sense at all. I can draw 2 amps  or 0.25 amps and it changes the lasting run time by only like 15 minutes?

That doesn't make any sense!

Joe WB9SBD
--

The Original Rolling Ball Clock
Idle Tyme
Idle-Tyme.com
http://www.idle-tyme.com



--
Howard L. Brooks
Professor of Physics and Astronomy
241 Julian Science and Mathematics Center
DePauw University
2 E. Hanna Street
Greencastle, IN 46135
hlbrooks@...
Office: (765) 658-4653
FAX: (765) 658-4732

Payload Power Sources

Joe WB9SBD
 

I am very confused on a battery pack.

Say you have a pack that can run 1 amp of current draw for 10 hours.
One would think that if you only drew 0.5 amps that it should run for 20 hours or close to it true?

Now many of you old timers here will remember these awesome surplus packs that looked like this.

These things were OLD like 20 years old when we used them yet the power they could provide was incredible!
They were rated at 7500mah, incredible! Sadly this supply of "NOS" dried up and new packs were very prohibitive in prices. Easily ending up being like $100 bucks a flight!

But I found a source for Brand new ones, that would make it like $15 to $30 bucks a flight! YES!

But it's performance curve makes absolutely no sense to me!

This makes zero sense at all. I can draw 2 amps  or 0.25 amps and it changes the lasting run time by only like 15 minutes?

That doesn't make any sense!

Joe WB9SBD
--

The Original Rolling Ball Clock
Idle Tyme
Idle-Tyme.com
http://www.idle-tyme.com

Re: Great Floater Race

stan siems
 

I think it sounds like a Great idea. Hope every one on here is  ok  group kind of died this week!

Stan

On 3/26/2020 3:53 PM, Jim Reed wrote:
I thought I read at one time that some were thinking about doing this. MN starts distance learning on March 30 as do many other states. We would love to build some lessons around it for our students. If you do this activity, please let us know. It would be fun to follow.

Take care everybody and stay safe!

Jim Reed

Great Floater Race

Jim Reed
 

I thought I read at one time that some were thinking about doing this. MN starts distance learning on March 30 as do many other states. We would love to build some lessons around it for our students. If you do this activity, please let us know. It would be fun to follow.

Take care everybody and stay safe!

Jim Reed

programing problem HELP

stan siems
 

I have a lightaprs w I just received and am working on programing it.   I down loaded and installed the driver, installed the latest Arduino pgm. As instructed I open Arduino go to preferences  type in the address for mightycore  go to tools -board manager and the down load is not there! and there is an error message that it failed to download. What am I doing wrong!

Thanks Stan

Re: The properties of latex / was Re: [GPSL] COVID-19 and GPSL

BASE_DePauw
 

This conversation reminds me of some work my students did several years ago.  Attached are a few slides from our presentation at the 2013 GPSL in Pella.

That work was inspired by Ron K6RPT's long duration floaters and relates to Joe WB9SBD's comments about the stretching of latex.

If you revisit CNSP (Ron's) flight to Morroco, the float altitude increased each daylight period.  A  simple explanation would be that the strong UV in the stratosphere degraded the latex, reducing its tensile strength, and eventually allowing the balloon to reach burst diameter.

Howard, KC9QBN
BASE_DePauw

Re: The properties of latex / was Re: [GPSL] COVID-19 and GPSL

Joe WB9SBD
 

I was just wondering what the tensile strength on the average actually was. So then even when fully inflated how much pressure it could actually generate before failing.

I had all the formulas for pressure vs diameter skin effect it was a pretty complex formula,

Funny thing was my bench tests came in very very close to the tests that someone made with a pressure gauge!

Joe WB9SBD

The Original Rolling Ball Clock
Idle Tyme
Idle-Tyme.com
http://www.idle-tyme.com

On 3/22/2020 8:36 PM, Hank Riley via Groups.Io wrote:
Joe,

When you say "many many" I'm curious why you did those tests?  Any special reason other than curiosity?

Do you have any tables or graphs you could provide, or write up for this list?

Hank
_____________________________________


On 3/22/2020 3:29 PM, Joe WB9SBD wrote:

We have tension tested many many samples of latex

The properties of latex / was Re: [GPSL] COVID-19 and GPSL

Hank Riley
 

Joe,

When you say "many many" I'm curious why you did those tests?  Any special reason other than curiosity?

Do you have any tables or graphs you could provide, or write up for this list?

Hank
_____________________________________


On 3/22/2020 3:29 PM, Joe WB9SBD wrote:

We have tension tested many many samples of latex