Telecon tomorrow (Thursday) @ 5 pm Eastern time

Hi all!

We'll have our last telecon of 2021 tomorrow (Dec. 16 in North America, Dec. 17 in Australia) at the regular time: 5 pm Eastern (2 pm Pacific, 11 am Hawaii, 23.00 European, 9 am Eastern Australia). Colton Broughton has continued working and finding critical issues! (which we're solving) -- with our operation of the two Raveon M8S 144 MHz transceiver boards. (Specifically, the ground of the adjustable power supply which we have been using to provide +12V for Vin of the boards has a different ground [by about 150 mV] than the USB/Arduino ground we have been using for its digital I/O -- which has been causing problems that we'll solve by instead providing the +12V with a LiPo battery -- which we'll need to do onboard and on ground stations in the field in any case.) Progress also continues to be made on optical simulation and on measuring electrical characteristics of the photodiode readout. More discussion items for tomorrow's telecon include: flight/telescope plans and tests; construction and lab tests of the new gondolas/payloads; light sources and light source modelling; goniometric and pre- and post-flight calibration; propulsion work; nanosat bus and payload solid models; computing / website / TWiki forums and e-mails; grant applications; and recap of schedules. I'll send a progress report before the telecon tomorrow.

Here's how to connect:

1) Open Skype on your computer (note that of course, you should first install Skype, http://www.skype.com, on your machine if you haven't already).
2) In the "Contacts" menu, add me ( jalbertuvic ) as a contact, if you haven't already.
3) Just wait for me to Skype-call you at the usual time (5 pm Eastern, 2 pm Pacific, etc).
4) If there is any trouble, or if you don't get a Skype-call for some reason and would like to join, please just send me an e-mail (jalbert@uvicNOSPAMPLEASE.ca).

Here's the tentative agenda:

I) Flight & telescope plans, and upcoming tests
II) Construction, drop tests, and other tests of the new gondola and payload
III) Diffused light source and its modelling, pre- and post-flight calibration, and goniometric calibrations
IV) Solid modelling
V) Computing/website, including recent flight control and simulation progress
VI) Grant applications
VII) AOB

Talk to you all tomorrow, thanks!!!
justin

-- jalbert - 2021-12-16

Hi all,

My apologies for the delay! -- here's the update on recent ALTAIR balloon work, minutes of the meeting two weeks ago on Dec. 2 (attendees Arnold Gaertner [NRC], Liviu Ivanescu [Sherbrooke], and me), and a reminder of the telecon in 20 minutes(!) from now:

Colton Broughton has made lots of Arduino code updates for, and new tests of our two 144 MHz Raveon M8S data modem transceivers. For the telecon two weeks ago, I mentioned that he needed to update his code to utilize the CTS/RTS flow control I/O from the transceivers (since without using that I/O, we were getting lots of junk characters interspersed within the transmitted signal). Colton made and tested those updates, and his new code works a lot better than it did before -- no more junk characters! Colton's new code can be found in:

https://particle.phys.uvic.ca/~jalbert/ALTAIR_M8S_Colton8dec21/

(as compared with his older code within https://particle.phys.uvic.ca/~jalbert/ALTAIR_M8S_Colton17nov21/ ).

But there was still some unexpected behaviour from the transceivers when either one was connected to attempt to ensure that the digital signal ground taken from the Arduino connections to the transceiver was connected to and thus identical to the ground reference for the +12 V input voltage Vin for the transceiver (the latter of which was taken from the reference ground of the adjustable power supply that we were using to provide Vin). When those two grounds were connected together to attempt to ensure that the two grounds were at the same potential, the transceiver ceased to receive (although it continued to transmit).

I thus asked Colton to check if there was a significant potential difference between the two grounds if they were not connected together, and he found that indeed there was -- about a 150 mV difference. (So in hindsight, the reason that the transceivers ceased to function when the two grounds were shorted together is that probably quite a bit of very-low-voltage current was flowing across that intentional short, and disrupting either the Arduino and/or the transceiver.) Thus, I have set up a LiPoly battery to replace the adjustable power supply as the supplier of the +12 V Vin for the transceivers -- and thus hopefully that will solve this problem (since the battery has a floating ground, of course). Colton will be trying that battery replacement out this afternoon.

Andrew Macdonald is away on break until January, so we'll get updates, including his completion of the population, and then the testing, of our three fabricated ALTAIR photodiode readout / transimpedance amplifier boards, when he returns at the beginning of 2022. (As a reminder, a photo of two of the three new boards from a few weeks ago can be seen at

.)

Colton Broughton, Sarah Alshamaily, and Will Stokes have also completed installing AIFCOMSS ( https://github.com/ProjectALTAIR/AIFCOMSSwithCUPredictorTest ) on their laptops. I've updated AIFCOMSS to work with the recent Cesium v1.83, as well as the instructions, and they all report success with this update and those instructions. The next two things that we know most definitely will need updating (or, rather, creating) are the station-keeping software for AIFCOMSS, and the online command-handling within the onboard Arduino software -- and I'll also be working on those over the next 2 weeks.

Regarding the latest news on our four Radiometrix SHX1 144 MHz transceiver modules that were returned to us from Radiometrix (following their firmware update to fix the BUSY output):

and the problems that Colton found with them (i.e., that of the 12 radio TX to radio RX permutations between those 4 boards, only 3 of the 12 permutations work, 3 of the other permutations give spotty connections -- e.g. only around 1 out of every 5 characters gets successfully transmitted -- as if one is transmitting and the other is receiving on neighbouring channels, but not the same channel..., and the remaining 6 permutations do not successfully receive any transmitted characters) -- we sent an e-mail to Radiometrix to ask about this about 3 months ago. They then sent back an e-mail a week later asking for more information, and Colton replied to them the next day providing the info (just a query about what logic voltages we were using -- we've being using 5V TTL from our Arduino Megas). Radiometrix has not replied to us since that e-mail reply sent to them 11 weeks ago, and thus I pinged them 9 weeks ago to follow up, and again 4 weeks ago -- and Radiometrix hasn't replied to those yet either.

We also still need to test out our new DFRobot SEN0177 payload aerosol monitors that we have here:

I've begun to look some more at MEEP (https://meep.readthedocs.io/en/latest/) for finite-difference time domain (FDTD) simulation of integrating sphere output, but I haven't yet had time to make any ALTAIR-relevant significant progress there yet -- I'm hoping to do that in the next couple of weeks. It will be interesting to compare that with ray tracing simulations, when I can get a chance to do that!

Engineering students Josh Gage and Evan Moore found that the "wings" that Josh had found in the laser diode light output distributions:

were due to how the diode was mounted in the heat sink. When the diode is mounted properly and carefully, the wings go away.

We also have our 10 Hamamatsu S12698-01 photodiodes and 3 Thorlabs FDS100-NOCAN photodiodes (those Thorlabs ones have their windows removed) here in Victoria:

I've given them to Evan to try out -- he's taking a few weeks to ramp up, and will produce some linearity, etc., plots from them soon.

The survey-tripod-mounted device to cross-check yaw-pitch-roll information from the gondola (e.g., on days before/after flights) is also constructed now, thanks to Mark Lenckowski -- photo at:

and all that remains to be done is to finish the small fitting between the device and the bottom of the payload. The purchased hardware in it includes both the survey tripod (http://www.cpotools.com/cst-berger-60-alwi20-o-aluminum-tripod-with-quick-release--orange-/cstn60-alwi20-o,default,pd.html), two adjustable angle mounts (http://www.thorlabs.com/thorproduct.cfm?partnumber=AP180), and a rotation mount (https://www.thorlabs.com/thorproduct.cfm?partnumber=RP01). That last fitting to attach (temporarily, pre-or post-flight) the upper adjustable angle mount to the payload landing gear has been started and will be completed here in the next couple weeks.

We're currently revising the draft initial contractual agreement from our colleagues at Globalstar Canada regarding 2 initial SPOT Trace devices (and their service plans) for the educational side-project for the upcoming NATO SPS application, in which classrooms in elementary and high schools could launch company-donated SPOT Traces using party balloons (or a more environmentally-friendly version thereof), and track them to learn more about winds at different levels in Earth's atmosphere.

Houman will send Cordell and/or us updated sections of his master's thesis soon -- that information will be extremely useful to us going forward. Also, Susana and Nathan, it would be very helpful for us all to get the JHU students' final writeup when you have a chance.

Next grant application will be a NATO "Science for Peace and Security" application (together with Australian colleague partners).

Our next telecon is in 20 minutes from now -- see below for Skype instructions.

Cheers, talk in 20 mins (!) from now -- thanks all!

justin

-- jalbert - 2021-12-16