altusmetrum February 2015

altusmetrum@lists.gag.com

11 participants
8 discussions

group project for Thunda in 2015?

by Bdale Garbee

Keith and I both hope to be able to attend "Thunda Down Under"[1] in 2015, and I've sent the organizers email requesting information on what it takes to be treated as an on-site vendor. Of course, it's always more fun to be at a launch when you have something interesting to fly! Thus, while Keith and I might each show up with a modest "travel rocket" of some sort... I've started pondering possible larger "Altus Metrum" group projects. Since transporting a large airframe to Australia would be a hassle, I wonder if a group project to build an airframe in-country makes more sense? To that end, I'd be pleased to know if any of our friends and customers in Australia want to sign up to help with such a project? My thoughts would be to engage in some group-think about project scope and goals, then hope friends in-country would take on the sourcing and preparation of suitable airframe materials. Depending on who wants to participate and how tasks get taken up, we might plan to arrive a bit early to help with any final assembly or other preparations, installation of suitably fresh Altus Metrum electronics, etc. So, to all our Aussie friends... does this sound like fun? If so, please chime in with a reply. I don't expect the email associated with such a project to be too heavy a load for this list to carry, but we can always spawn a dedicated lists.gag.com list if I'm wrong. Regards, Bdale [1] http://thunda.com.au/

5 years, 10 months

Re: [altusmetrum] Contact Form

by Kurt

Not working here. I tried the D72A and paired a Mobilinkd TNC1 to a Nexus 7 with a plain H/T. Packets come across but nothing is decoded. With the Mobilinkd, I made certain it was decoding APRS packets properly off the air on 144.390 and then used a 70cm Beeline GPS. All worked fine there including packets transmitted from the D72A and off-frequency D7's. I could "hear" the data packet on the TeleGPS coming in but no decode. Does a separate APRS packet get sent in between the GFSK data bursts or is it mixed in with the data bursts? If it's separate I do not hear anything that resembles the APRS sound. If it's "mixed in" with the Altus metrum format, it sorta sounds like an APRS packet but is not decoded. Nonetheless, if my settings are appropriate, I believe the TeleGPS I have is not behaving up to spec if it's supposed to be able to send an APRS packet. I'll wait till I hear from Keith or B'dale and see what they say about my settings. I've used three rigs to attempt to decode packets (although I didn't expect much from the off frequency D7) two of which work fine with 2 meter and 70cm off-air packets. I'm stumped. Kurt KC9LDH ________________________________ From: Douglas Bertelsen <douglas.bertelsen(a)gmail.com> To: Kurt <ksaves2(a)sbcglobal.net> Sent: Saturday, January 31, 2015 9:26 AM Subject: Re: [altusmetrum] Contact Form Those settings gave me good packets. All else failing, can you record the audio from the radio during transmissions and post it if those settings don't work? I can compare it to what I hear and maybe give some insight. Doug

7 years, 10 months

Balls TeleMega bug report

by Andrew Wimmer

I flew my TeleMega, serial #1639 with 1.4.1 at Balls in a 2 stager. Ran into a few problems, as follows: 1. Unable to connect in to TeleDongle in idle mode. I had previously found that I couldn't get a connection with the TeleMega in channels 7-9, so I was using channel 3 for this flight. I was unable to get a connection in idle mode in Channel 3. I haven't explored other channel or tried to re-create this problem. 2. RFI issue with Beelines. The rocket had 4 Beeline trackers in it as follows: - 1x 100mw 70cm GPS aprox 30" above the TeleMega on 434.350 - 1x 70cm beacon aprox 6" below the TeleMega on 438.850 - 1x 16mw 70cm GPS aprox 48" below the TeleMega on 434.350 - 1x 70cm beacon aprox 48" below the TeleMega on 438.350. With any combination of the beacons turned on, attempting to startup the TeleMega in pad mode would result in battery voltage beeps, pad mode beeps followed by silence, on both the radio (I was listening in to 434.850 on my FT1DR) and buzzer (ie, no continuity beeps). After spending an afternoon troubleshooting this, it was determined that turning on any combination of the Beelines prior to startup would cause this, but turning them on after the TeleMega was transmitting didn't result in any adverse affects. In investigating the manual post-flight, I did note the point about twisting wires, which I did not do on this flight as I hadn't seen it previously. I'm not certain that that would have fixed the issue or not. It would be really really great if there was a separate manual for each product. It's very easy to miss things when you are intentionally skipping a significant portion of the manual since it doesn't relate to the product you are interested in. Additionally, this is the only time I've seen a suggestion in a manual to twist wires. This comes in a section of the manual, that in most other rocket electronics manuals, is reserved for things like "how to attach wires to screw terminals" and "how to not have battery issues", which experienced fliers have a tendency to already know and skim. 3. Accel calibration with temp. After spending an afternoon at the pad troubleshooting the above issue, the rocket sat overnight and was powered up within 30 minutes of sunrise. I was unable to get the TeleMega into pad mode until it had been in the sun for 10 minutes, at which point, it went into pad mode and read a Z accel of -5.1m/s/s. We left the rocket in the sun for the next 45 minutes and in that time, the Z accel when it was being held vertically had migrated from -5.1 to -3.3 to -2.2 and was continuing its upward trend. The accelerometer was previously calibrated at room temp 2 weeks prior to the launch. 4. Angle lockout for staging-not so much a bug as it's probably exactly what it's designed to do, but I had the telemega setup to do staging and also staging inhibit on a backup timer. The TeleMega was to stage if conditions were after burnout, >4 seconds into flight, <25 degrees and >400m/s. I had an additional circuit acting to open the igniter circuit on a timer I was using for backup. This was to occur if the angle exceeded 25 degrees at any point. Shortly after the breakup, the inhibit circuit fired as anticipated. What I didn't expect was for the fire circuit to fire as the rocket rolled back within 25 degrees of vertical 2 seconds later. Fortunately the igniter had already ripped out of the motor, so no harm was done, but this could have been interesting had it not. Anyway, hopefully this helps alleviate frustration for at least someone. I understand the issues now and they're more annoyances that I can live with than anything. As I hadn't seen them documented previously, I figured I'd put them out there. Let me know if anyone has further questions or needs more elaboration. Thanks, -Andrew

7 years, 11 months

Re: [altusmetrum] Antenna question

by Bdale Garbee

wexpeter <wexpeter(a)gmail.com> writes: > Have used Telemetrums over the last few years - very happy with the > product. Thanks for the kind words, Peter! > A university rocketry club my son is in is considering a carbon fiber > HPR. They are considering 900MHz — I am trying to convince them to get > the license and use the Telemetrum. Question is what others have used > for an antenna. My assumption is it has to be external if carbon > airframe. Single external wire? Other suggestion? Clearly some gain on > the ground will be important.They are thinking possible max altitude > of 50K. Any suggestion greatly appreciated. > > Peter Wexler > WA2COM > LUNAR/NAR/Tripoli I'm going to CC our mailing list on this reply in case others want to chime in, because the whole issue of what to do for antennas on predominantly CF airframes is a fairly frequent question to us. My personal preference is to include a non-CF section in the airframe. For example, make the walls of the electronics bay out of glass, or use a glass nosecone, into which the various antennas can be places. The reason this is a big win is that you're actually worrying about *2* antennas, not one .. the GPS patch needs a clean look at the sky or you won't get a GPS lock, and the signal from the UHF downlink antenna obviously needs to be able to propagate out from the airframe. In our original TeleMetrum design, we were forced for several reasons to use a GPS patch antenna with an integrated preamp that had a short piece of small diameter coax wrapped around the board plugged into a U.FL connector on the board. With those boards, remoting the GPS antenna was at least theoretically pretty easy. You could disconnect that cable, put in a U.FL extension or U.FL to SMA adapter cable, and put the amplified GPS antenna of your choice somewhere else in the airframe. But in practice, this often turned out to be a real pain. The U.FL connectors aren't really designed for many insert/remove cycles (think 10'ish), adapters are expensive / heavy, as are standalone amplified GPS antennas. Thus, not many people actually did this... In our current products, all of the GPS antennas are passive patches soldered directly to the board. The front-end on the u-blox MAX-7Q GPS receivers we're using now is sensitive enough that this works out pretty well, and the inclusion of a SAW filter plus *very* carefully designed layout keeps the UHF transmitter from swamping the GPS receiver input. The downside is that remoting the GPS antenna has gotten a lot harder with current products like TeleMetrum v2.0 and TeleMega. We no longer offer a purchase-time option for putting an SMA connector on the board instead of a wire whip antenna, but the footprint is still there, and I still sell the right SMA connectors. We've observed that downlink signals from a simple wire soldered to the board are often much stronger than when you put a "commercial" antenna on an SMA .. this is partly because most "rubber ducks" are actually really lousy antennas (including the ones we used to sell, sadly!), and partly because the design of the PCB is such that a simple 1/4 wave whip on the end of the board gets an exceptionally good signal "launch". So, if you really want to remotely mount a UHF downlink antenna, it's not hard to do, but we don't usually recommend it. For a good example of when/why you might want to do it, have a look at my write-up for YikStik3, particularly the description of my "fintenna" and the associated photos taken during the build: http://gag.com/rockets/airframes/YikStik3/ http://gallery.gag.com/rockets/YikStik3/Build/cimg1949.jpg The performance of the fin-can downlink on that airframe, once I re-tuned everything with the Pro75 6xl case in place, was *outstanding*. I really wish I still had that airframe... on its maiden flight it set new personal speed and altitude records for me. But, like so many others, it was lost in the fire. Bottom line? It's *possible* to remote antennas from our products, but it's not something to be taken lightly. By far, the better approach is to include an RF-translucent section somewhere in the airframe to house the board(s). There are so many different "900 Mhz" products out there that I can't speak to them without more details, but you're unlikely to find anything operating on that band that gives a more satisfying result than using one or more of our products... ;-) I hope this helps! Bdale

7 years, 11 months

Unable to flash TeleBT to 1.6

by Kevin Ruland

Hi, After the release of the 1.6 AltOS, I tried to flash the firmware on my teleBT. The program can connect to the TeleBT and I select the telebt v1.0 1.6 file. It ends up erroring out with "Debug port not Connected". Any ideas? Kevin

8 years, 1 month

[AD] Altus Metrum announces AltOS 1.6 with TeleDongle v3.0

by keithp＠keithp.com

Altus Metrum announces AltOS 1.6 with TeleDongle v3.0 Our updated ground station, TeleDongle v3.0, works just like the original TeleDongle, but is an all-new design: * CC1200 radio chip is about 5dB more sensitive than TeleDongle's CC1111. * LPC11U14 CPU can be reprogrammed over the USB link. Bug fixes in the AltOS firmware: * Make sure the startup flight computer beeps are consistent. Sometimes, it was taking long enough to beep out the battery voltage that the flight computer state was changing in the middle, causing a bit of confusion. * Change TeleDongle's LED indicators during telemetry reception. The green LED blinks on successful packet reception, and the red LED blinks when a packet with an invalid checksum is received. * The SPI driver used in both TeleDongle v3 and TeleGPS has been rewritten to avoid locking up under heavy CPU load. If you've got a TeleGPS board, you'll want to reflash with new firmware. New features in AltOS for Linux, Mac OSX and Windows: A few minor new features are in this release * AltosUI can now compute and display tilt angle when graphing eeprom log data from TeleMega and EasyMega. * The AltosUI tool window is shown when starting with a data file. This way, when you double-click on a file in the file manager, you'll get the whole AltosUI interface, rather than just the graphing window. * At the end of replaying an old log file, stick 'done' in the Age field so you can tell the recording is over. And a few bug fixes in AltOS, mostly for Windows: * Use a different Windows API to discover USB device ids. This works better on my new HP Windows 7 machine. Maybe it will work better for other people too? * Look in more places in the Windows registry to try and find the installed Java version. It appears that the default Java download from Oracle is a 32-bit version? In any case, that version sticks its install information in a different spot in the registry. * Fix file associations on Windows when Java isn't installed in the system root. * Make 'Scan Channels' work better with new AltOS firmware which only reports device configuration information once ever five seconds. ` You can read more about this release on the AltOS web page: http://altusmetrum.org/AltOS/ Altus Metrum products are available from our distributors Apogee Components, Bay Area Rocketry, and Chris' Rocket Supplies in the US; Australian Rocketry; Rebel Space in the Netherlands; Sierra Fox Hobbies in Italy; and Aerospace Education in New Zealand. Or you can order directly from Bdale's web store at: http://shop.gag.com All Altus Metrum products are completely open hardware and open source. The hardware design details and all source code are openly available for download, and advanced users are invited to join our developer community and help to enhance and extend the system. You can learn more about Altus Metrum products at http://altusmetrum.org. Thank you all for your continuing support of Altus Metrum, and we hope to see you on the flight line! Bdale and Keith

8 years, 1 month

Pyrochannels broken(?)

by Andreas.Pahler＠gmx.de

8 years, 1 month

Re: [altusmetrum] Contact Form

by Bdale Garbee

Web Customer <am-query(a)gag.com> writes: > I was wondering if there are any updates regarding availability of > teledongles or teleBTs. What's the latest expected return? Hi Dave! Thanks for your email and interest in our products. We've re-designed both TeleDongle and TeleBT to take advantage of an improved radio chip that gives several dB better receiver sensitivity. The first production batch of TeleDongle v3.0 are in process right now, and I hope to have them available for sale sometime (early?) in February. TeleBT v2.0 first prototypes are also in process, if all goes well I hope we'll have those for sale a month or so after TeleDongle v3.0. Bdale

8 years, 1 month

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altusmetrum February 2015