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Telecon tomorrow (Thursday) @ 5 pm Eastern time

Hi all,

Telecon tomorrow (Feb. 25 in North America, Feb. 26 in Australia) at the regular time: 5 pm Eastern (2 pm Pacific, noon Hawaii, 23.00 European, 9 am Eastern Australia). Evan is presently testing the solution to that "very interesting" bias current issue with the ADA4522-1 op amp on the transimpedance amp board, by replacing it with an AD8638 op amp with the same chip footprint and pin-outs. Also more news on other electronics work done by students Mike Huynh and Josh Gage, and a little bit more work on optical simulation from me. We additionally have recent updates on AIFCOMSS, and on the 144 MHz transceivers (Raveon and Radiometrix). 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

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

Talk to you all tomorrow, thanks!!!

-- jalbert - 2021-02-24

Hi all,

My apologies for the delay! -- here's an update on recent ALTAIR balloon work, minutes of the last meeting on Jan. 14 (attendees Arnold Gaertner [NRC], Liviu Ivanescu [Sherbrooke], and me), and a reminder of the telecon in 10 minutes(!!!) from now:

Our electrical engineer Evan Moore is presently testing out the solution of replacing the ADA4522-1 op-amp on the transimpedance amplifier board with a AD8638 op-amp -- things are going fine so far with his testing of that -- he needed a shielding box and some triaxial cables to be able to use the low-noise triax connections to the Keithley 2450 for that, so I purchased those yesterday:

and they should be arriving today. Evan should have that testing done by early next week. (Then we can finally move onward with producing the ALTAIR version of that board.)

For our later precision testing (in a couple months from now), we have very good news from Guildline Instruments -- they are offering us an excellent special deal on one of their 9334-1M 1 Mohm calibrated metrological resistors. We will order that tomorrow, and hopefully get it within a few months (metrological resistor suppliers such as Guildline often take a few months or so to send out orders, since they need to specially-calibrate every one)!

There are some ORCASat payload mechanical updates from Josh Gage -- which we will probably eventually also implement on ALTAIR -- that are described in the following slides and laser diode heat sink assembly manual from Josh Gage. (Remember that ORCASat uses bare laser diodes with a Thorlabs OEM laser diode controller board, however ALTAIR uses [larger, but of course easier to work with] fiber-coupled laser diode modules from World Star Tech):

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!

Radiometrix still has our four SHX1-144 transceiver modules (they arrived there on Apr. 6) and is doing their firmware update that solves the BUSY output issue. They'll then test them out and send them back to us. Due to the COVID-19 situation in the UK, they've been taking a very long time; the UK is enduring its second wave of COVID, and with even-more-highly-transmissible COVID variants, and the country is still under a lot of restrictions as a result. Our department electrical engineer Nick Braam sent them an e-mail back on Monday, Dec. 14 to check up on when they will (finally) be sending the firmware-updated SHX1 modules back to us, to which they still haven't replied. (We'll be sending another check-up message this coming week.) In the meantime, we've also been doing more connecting up and testing out of our two new 144 MHz Raveon M8S data modem transceivers here in Victoria:

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 those 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 10 minutes from now -- see below for Skype instructions.

Cheers, talk in 10 mins (!!!) from now -- thanks all!


-- jalbert - 2021-02-25

Title Telecon tomorrow (Thursday) @ 5 pm Eastern time
Forum ForumGeneral
Topic attachments
I Attachment History Action Size Date Who Comment
PDFpdf DigiKeyINVOICE_79058186_24feb21.pdf r1 manage 146.0 K 2021-02-25 - 22:21 JustinAlbert Faraday cage shielding box purchase from Digi-Key
Unknown file formatdocx JoshGageHeatSinkAssemblyManual.docx r1 manage 6448.3 K 2021-02-25 - 22:23 JustinAlbert ORCASat heat sink assembly manual from Josh Gage, version as of 17 Feb 2021
PDFpdf JoshGageORCASatMeeting2020-02-17.pdf r1 manage 391.3 K 2021-02-25 - 22:22 JustinAlbert ORCASat mechanical update from Josh Gage on 17 Feb 2021
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Topic revision: r2 - 2021-02-25 - JustinAlbert
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