Telecon tomorrow (Thursday) @ 5 pm Eastern time

Hi all,

Telecon tomorrow (May 13 in North America, May 14 in Australia) at the regular time: 5 pm Eastern (2 pm Pacific, 11 am Hawaii, 23.00 European, 7 am Eastern Australia). Our 4 SHX1 144 MHz transceiver modules have now been soldered back onto their transceiver boards by Nick Braam; and Andrew Macdonald has now produced a schematic and is working on the layout for the new ALTAIR form-factor version of the ORCASat transimpedance amp board. Progress also continues to be made on optical simulation and on measuring electrical characteristics of the photodiode readout. We additionally have recent updates on AIFCOMSS, etc. 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 - 2021-05-13

Hi all,

My apologies for the delay! -- here's an update on recent ALTAIR balloon work, minutes of the last meeting on Apr. 29 (attendees Arnold Gaertner [NRC], Liviu Ivanescu [Sherbrooke], and me), and a reminder of the telecon in 15 minutes(!) from now:

Nick Braam in the physics & astronomy electronics shop soldered the Radiometrix SHX1 144 MHz transceiver modules (that were returned to us a few weeks ago from Radiometrix, following their firmware update to fix the BUSY output) back onto their transceiver boards:

Both Nick and I thought that he would also need to add a slider switch onto each board, so that we can easily switch between RS-232 vs. UART serial connection to the boards, but it turns out that all we need for the latter is to remove the jumper on the board -- rather than having to unsolder the MAX3232 chip from the board -- so all that time when we previously were using the boards, we had been unnecessarily unsoldering, and soldering back on, the MAX3232 chip, whenever we switched connection types! Sigh. It's good that is realized now!...

However, what Nick didn't have time to do is to check out the functionality of the boards (and their new BUSY signal) at all -- all he did was solder on the transceiver modules. So I'll need to test the boards during the next couple of weeks...

And, regarding the (entirely separate, of course) TIA board, Andrew Macdonald is still working hard on the ALTAIR form-factor version of the ORCASat transimpedance amp boards -- last week he produced a new schematic for it:

to go along with his spec sheet here:

) and he should finally have layout and Gerber files by next week, and will send them out for fabrication the week after.

We heard back from Guildline that our metrological 1MOhm resistor should arrive by next week. (We got an e-mail reply from them saying "The resistor was calibrated but requires further adjustment. I just spoke with the metrologist and he's hoping we'll be able to ship by end of week." -- it was nominally supposed to arrive here at the end of April). When that arrives, we can use it together with our precision 1/1000 voltage divider, using one of these precision matched combined resistors: https://www.digikey.ca/en/products/detail/caddock-electronics-inc/1776-C6815/4360753?s=N4IgTCBcDaIIwHYEDYC0BhZAOOBWVAcgCIgC6AvkA and an ultra-low-offset-voltage op-amp: https://www.digikey.ca/en/products/detail/texas-instruments/TLC2652AIP/277463?s=N4IgTCBcDa4JwDYC0BGAHOpBWJA5AIiALoC%2BQA , and also our PDVS2mini calibrated voltage source (https://www.ianjohnston.com/index.php/onlineshop/handheld-precision-digital-voltage-source-2-mini-detail), so that we can reliably and very precisely put 1 uV (or even 500 nV) through the Guildline 1MOhm resistor to have a very precise 1 pA (and/or even 500 fA) current source for calibrating the TIA boards.

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 significant progress there -- 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!

We'll be doing more connecting up and testing out of our two new 144 MHz Raveon M8S data modem transceivers:

After checking them out with Raveon's Windows-based Radio Manager software, I've started to connect the radios up to Arduino Megas -- in the next few weeks I'm planning to get them talking to one another, and then I'll check out their effective ranges.

Once we get our 144 MHz transceivers settled and back into the ALTAIR gondola, we'll do some outdoor drop testing of the actual gondola. (We've done all the outdoor drop tests I can think of doing with our dummy gondola.)

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

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 15 minutes from now -- see below for Skype instructions.

Cheers, talk in 15 mins (!) from now -- thanks all!

justin

-- jalbert - 2021-05-13