Discussion Forum » General »

Telecon tomorrow (Thursday) @ 5 pm Eastern time

Hi all,

Telecon tomorrow (Sep. 26 in North America, Sep. 27 in Australia) at the regular time: 5 pm Eastern (2 pm Pacific, 11 am Hawaii, 23.00 European, 7 am Eastern Australia). Updates on testing of the windowless Hamamatsu photodiodes with the new amplifier boards, on telemetry, one some new equipment just received from Thorlabs, on the drop-testing pole status (we're allowed to raise it again!), and also some more progress on AIFCOMSS station-keeping prediction/simulation software. More discussion items for tomorrow's telecon include: flight/telescope plans and tests; construction and lab tests of the new gondola/payload; 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 an update with some recent photos, etc, 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


Talk to you all tomorrow, thanks!!!


-- jalbert - 2019-09-25

Hi all!

Apologies for the delay! -- here's a quick update on ALTAIR balloon work over the past 2 weeks, minutes of the meeting 2 weeks ago (attendees Arnold Gaertner [NRC] and me), and a reminder of the telecon in 90 minutes from now:

Student Peter Ogilvie did an initial linearity test on one of our windowless Hamamatsu S2386-8K photodiodes -- his results look excellent (when the photodiode is 5V reverse-biased in the case of higher photocurrents), and can be seen here:

That plot can be compared with the analogous plots for a Thorlabs FDS-100 photodiode and an OSI Optoelectronics UV-015 photodiode seen in the minutes from 4 weeks ago at https://wiki.heprc.uvic.ca/twiki/bin/view/Forum/ForumGeneral0036 . Peter also notes that "There is a [small] discontinuity at 7.5 mW [on the above S2386-8K linearity plot], this is a result of turning the laser off for a period of approximately 2 minutes and should be ignored."

Today we are ordering three windowless FDS-100 photodiodes from Thorlabs and ten S12698-01 photodiodes from Hamamatsu (not windowless, but with special UV glass and hermetically sealed -- that's what they sell them as, they weren't willing to offer them windowless); those will both arrive in New Hampshire in late Oct. or early Nov., and I'll bring them back up to Victoria at xmastime. A couple weeks ago we ordered 12 extra standard FDS-100 photodiodes (with windows; we can see if we can take a couple of the windows off with our WR1 can opener that we got this summer), three new laser diodes (a 980 nm wavelength L980P200, an 840 nm wavelength L840P200, and an extra 660 nm L660P120 laser diode), and some new laser diode driver ICs (MLD203P1, MLD203P2, MLD203CLN, MLD203P1E, and MLD203CLNE), all from Thorlabs -- we have received them (photo at

and I'll bring them all back to Victoria with me when I fly back there the day after tomorrow (Sept. 28).

One very interesting thing that I did exactly one week ago was attempt (for a third and final time) to recover the SPOT Trace located near Charlie Lake, between Fredericton and Woodstock, NB, Canada, which we had flown from Hanover NH up to NB way back on 18 Dec. 2015 on a bunch of party balloons -- with that whole flight episode and its motivation (specifically for future school projects for education and outreach) recounted back in:


and with photos from 2015 in:


My first SPOT Trace recovery attempt was documented in those minutes above from Dec. 2015 -- I found the device and balloons out in the forest in NB, where they were supposed to be, but they were up in a tree and I didn't have a hacksaw nor any means then of getting the SPOT Trace down from that tree. Fast forward to last year -- I had been intending to make another attempt to go into the NB woods to recover the SPOT Trace, but I got the flu, and had to abort that attempt. Last week, I made my third attempt. I went to Canadian Tire in Woodstock NB last Wednesday and got a hacksaw, some string, and a "bear flare" to aid in the recovery attempt, and one week ago today I headed into the woods with my handheld GPS + cellphone GPS. The foliage had quite dramatically changed over these 4 years, and try as I might, I just couldn't find which tree the SPOT Trace had been up in. There were no longer any traces of the bunch of colorful balloons that had helped guide me to the exact right tree last time; those deflated balloons must have either biodegraded over the past 4 years, or perhaps birds had taken their remains to construct nests, etc, etc. So, I just couldn't find it, and I had to drive back to Boston that afternoon, and then fly to Chicago the following day, so I couldn't stick around there in the middle of the NB woods looking for it for any more than the few hours that I tried. So, sadly, I think we'll have to chalk that SPOT Trace up as lost (even though we found it a week after its flight in 2015; it had just been up in a tree!) The important lesson learned is that one can perhaps wait up to a week or so after such a flight to recover a flown SPOT Trace device; however one cannot wait 4 years, or even a year, and expect there to be any visible (and colorful) remains that would allow the device to be found.

I will resume drop testing in my backyard with the dummy ALTAIR payload after I get back to Victoria this Saturday (since I can now raise it in order to do drop testing again, since Saanich did not reply negatively to my notification to the municipality last month). We'll work on (and hopefully get in the next few weeks) a repeatable parafoil-folding recipe for assuring that the parafoil opens promptly following release.

I found what seems to be the main problem with the SHX1-144 144 MHz transceiver boards, which was confirmed by Andrew Macdonald in the electronics shop: the BUSY signal from these boards always reads 4 volts, either when the board is actually BUSY or not. (Interestingly, the 4V is not the 5V TTL used by the rest of the board -- but the main problem is that it never changes.) I still haven't heard back (after 2 weeks, and a couple of e-mails to them) from Radiometrix in order to figure out why this is the case, and if it is fixable (e.g., with new EEPROM code). I'll phone them (with a phone call to England) this coming week if I still haven't heard back by then. If it is not fixable, we can work around it, but of course it would be much better if it is fixable. We'll then resume integrating the SHX with the other (DNT900 and RFM23BP) telemetry.

I'm also working with student Zejia Xu on the actual station-keeping algorithm for AIFCOMSS. Presently the "station keeping" code in AIFCOMSS just turns on the propellers in the simulation at full power, and propels the gondola in a single direction until the battery runs out (it's presently most certainly not actual "station keeping"). I added some hooks for adding actual station keeping algorithms into the code, and we're developing the algorithms and will implement them.

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 applications will be a new CSA FAST (due Oct. 18) and a NATO "Science for Peace and Security" application, together with Australian colleague partners.

Our next telecon is in 90 minutes(!!) from now (see below for Skype instructions).

Cheers, talk in an hour and a half from now -- thanks all!


-- jalbert - 2019-09-26

Title Telecon tomorrow (Thursday) @ 5 pm Eastern time
Forum ForumGeneral
Topic attachments
I Attachment History Action Size Date Who Comment
JPEGjpg NewThorlabsLaserDiodesLDDriversAndPhotodiodes.JPG r1 manage 3946.9 K 2019-09-26 - 18:57 JustinAlbert New Thorlabs 660 nm, 840 nm, and 980 nm laser diodes; laser diode driver ICs; and twelve FDS-100 photodiodes. These will be brought back to UVic on 28 Sept. 2019.
PNGpng S2386-8KPhotodiodeResponseWithAndWithoutAppliedBias_660nm.png r1 manage 123.3 K 2019-09-26 - 18:19 JustinAlbert Plot from Peter Ogilvie's windowless Hamamatsu S2386-8K photodiode test on 25 Sep. 2019.
Edit | Attach | Watch | Print version | History: r3 < r2 < r1 | Backlinks | Raw View | WYSIWYG | More topic actions
Topic revision: r3 - 2019-09-26 - JustinAlbert
    • Cern Search Icon Cern Search
    • TWiki Search Icon TWiki Search
    • Google Search Icon Google Search

    Altair/Forum All webs login

This site is powered by the TWiki collaboration platform Powered by PerlCopyright & 2008-2023 by the contributing authors. All material on this collaboration platform is the property of the contributing authors.
or Ideas, requests, problems regarding TWiki? use Discourse or Send feedback