I entered 19, not 7.
I plan to have notes for the meeting up tomorrow.
I entered 19, not 7.
I plan to have notes for the meeting up tomorrow.
There is an HAB launch on Monday - something some folks out of Plano are working.
John Dinneen KC0L of Frisco mentioned it during a net this week. He operates some of the training nets at 8pm on 146.920 w5ngu repeater in Denton.
If you are interested, and if you are not able to get more info, someone in the Amature radio committee might ask around for you, if you request it. Or if you are licensed, you could probably find out more by getting on a repeater in Denton or Plano, or asking around with the clubs in Denton or Collin.
Thanks Michael! I’ll ask around.
After our meeting tonight, I was curious about the hardware required to get APRS up and running. For a very basic/stand-alone APRS system, we can use an old Android phone (I have one available), running APRSDroid with AFSK modulation plugged into the Baofeng U5VR with VOX enabled. This setup works great! Within about a minute, I was able to see my callsign appear on APRS.FI, being received by a Dallas area APRS ground station.
The advantage of this setup is that it’s really easy, and the Android phone can also serve as a data logger and video camera .The downside is weight. I’ll weigh this setup tomorrow.
I’ve updated our Wiki to reflect notes and tasks from last night’s meeting: https://dallasmakerspace.org/wiki/DMS_High_Altitude_Balloon
If I didn’t have that direct link, how would I find that page, or even know it exists?
You could search the wiki for “balloon”, or watch the “Recent changes” page like an OCD mental patient like I currently do.
I was afraid of that. This is off-topic, but one reason that I haven’t posted much to the Wiki is I was trying to figure out its structure. Apparently, it doesn’t have one.
The wiki has whatever structure its authors create. For instance nothing prevents you from adding the above wiki page as a link from within another, or more then one, page(s)
While sharing the same affliction I refuse to accept an OCD diagnosis…
In theory, the project could have a “Projects” and “Active Projects” category on the page, and you could find it that way (currently only the old one has a category for instance). That’s a quick fix for that one, the long fix is all the other stuff out there marked active that maybe aren’t active and projects with neither category.
I put in a request for the Interactive Classroom on Tuesday July 21st from 7pm-9pm for our next working session.
I added a link at the top of the old HAB project page to the new page with a note that the old project is inactive.
Notes I remember are as follows:
Currently we anticipate total weight to be in the neighborhood of 1lb (not counting balloon), which gives a 60k ft burst altitude with 6m/s ascent rate, and my 32" rocket parachute can give a descent rate of 4m/s.
Nick made a good case for the Pixhawk, and since it seems like a generally better solution we’ve decided to run with it. It sounded like Nick was extraordinarily familiar with it so we should be good.
Robert (I believe) suggested aiming to land at Caddo ntl. grasslands; after looking at maps I’m not sure if we have anything better to try, although now that I think about it we might out to check that it isn’t 90% forest. Also, there were concerns that might be rather close to an air corridor. Initial runs on the predictor website suggest we will land quite a ways away (20 miles or so), which leads me to …
We discussed having multiple ground teams. With 2 teams, we can station one at the predicted landing site. With more … I can see how we might use a third to get eyes on the balloon asap, but mostly they’d be scattered in the predicted landing region
region. Although something I just thought of that we didn’t bring up is a 50 minute flight would give the launch crew a lot of time to pack and go 20 miles to retrieve.
I’m happy aprs worked after I left. I wasn’t sure how difficult that would be. I have to admit I’m leaning on y’all since I’m not very knowledgeable when it comes to ham radio.
Action items were that Nick would focus primarily on his pixhawk and other electronics, Robert would look into aprs, and I would do ground equipment gathering. We will also reach out to the FAA (maybe through Romeo) for this first (non-drone) launch and bare minimum establish a dialogue; preferably they will tell us what they need us to do. With aprs solved (in theory), Robert may need something else to do. I’m having trouble thinking of things that aren’t covered; maybe balloon detail design (what type of cable to use, how the payload will be attached, possibly a smaller icebox, icebox ventilation, etc.).
We also discussed drop testing from a drone.
I’m thinking most of what’s left is detail stuff. No major uncertainties at this point in my mind. I think if we had 4 of us working 8 hour days it’d be done by this weekend.
We set a target launch timeframe at mid/late September to give Robert time for his schedule to clear out for launch. I think that gives 3 or 4 biweekly meetings remaining if we don’t count the one Robert will miss.
I think that covers the important things.
The link I built the wiki page under (the one Nick linked) is on aero committee’s page under “projects”. I didn’t see the original one until after I made the one we’re using.
I also put in a request for the 21st for the common area yesterday while I was trying to do the one for that night. I presume someone monitors the events submissions and will catch the double entry.
That looks great. I’ve seen a few similar projects, mostly based on an Atmel 328, GPS, and Radiometrix transceiver, none of them that are commercially available. I’ve just reached out to see if we can get or build one of their boards. One downside to the small integrated transceiver vs the Baofeng is lower transmit power (300mW vs 4W), but in practice, we’ll have to see how important power is. I’ve never worked with a HAB before, but I imagine having a direct LOS will negate the need for high power on our communications systems.
Your list looks good. One additional aspect I’d like to test with in addition to the 3DR telemetry is antenna tracking. The ground control station software that communicates with the Pixhawk already has code to drive a servo controller and move Pan/Tilt servos. I will try to interface it with a professional camera motion control system I already own (camBLOCK Adventure) If successful, we’ll be able to use high-gain directional antennas on the ground, and we also have the potential of mounting a telephoto lens or small telescope to the tracker.
When you DIY’ing a radio the FCC regs expect you to perform testing. This applies to DIY radio in the amateur bands as well. Also, remember antenna and height above ground both effect the effective radiated power of a radio.
Personally, I suggest using COTS radio like baofeng, unless the idea is to spend time developing and testing a radio as opposed to flying a package.
Hi Nick, saw your message in the Arduino forums and I figured I’d join in the fun here. I can tell you from a fair amount of experience that 300mw is more than enough power to transmit APRS from a weather balloon. I have used as low as 10mw at 100k ft without any problems what so ever. On previous flights I’ve been able to hit repeaters in Nevada from a launch in Maricopa CA.
As far as getting one of my boards I am trying to hold off giving out the source info until my kickstarter launches (sometime within the next month), but I would be more than happy to send you a demo unit. I have another round of boards and parts shipping and I expect them to arrive in about 2 weeks. Let me know if that works for you and I’ll set one aside for you.
That would be great - yes please set aside a board for us! Our initial launch date hasn’t been set yet, but will not be for several weeks out.
My only experience with APRS to date was a simple test driving through Dallas with a Baofeng attached to an android device running APRSDroid. I was surprised that so few of my packets were picked up, even with a number of digipeaters and igates around - but I know having LOS at high altitude makes a big difference!
When do you plan to launch your Kickstarter? We’d be happy to provide feedback / data / video from our project.