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/
We launched a two-stage flight last weekend attempting to break 100K again.
The sustainer ignitor failed (incomplete pyrogen burn), but the recovery
was mostly successful, and we'll try again next month.
In the updated design, we've got one TeleMega and one EasyMega each, for
both booster and sustainer. All four units worked great. Having a common
programming interface and terminal block across everything has really
simplified our lives!
We had a couple of questions arise out of the flight. They're all about
sustainer ignition. To be clear, the TeleMega clearly fired it because the
igniter was partly burnt. I'm just trying to understand the data a bit
better. Here's the .eeprom file:
https://drive.google.com/file/d/0Bw8Fmi_7rzqMVnBLN2pjZFloUDA/view?usp=shari…
1) We used the tilt angle lockout on the sustainer ignition. I can see this
is the tilt relative to the pad orientation immediately before liftoff
(ao_ground_roll/pitch/yaw). I see the derived ao_sample_orient goes in the
OTA telemetry, but not the eeprom log, which instead gets the ground values
stored in the header along with raw r/p/y. Presumably, that's enough data
to reproduce the same math. Unfortunately, I'm not good enough at java to
discern how these get plotted in the UI. When looking at the .eeprom graph,
is the "tilt angle" still the angle vs. pad orientation? (Or is that a
silly question, because the gyros only give rates not absolutes?)
I'm interested because the tilt angle graph seems to start at a flat,
non-zero value, roughly 3.7. We did launch at about 2 degrees off vertical
to compensate for wind, but I wouldn't expect that to show up in the plot
if it were relative to pad.
2) We also set a time window of >17 seconds and <19 seconds on the
sustainer ignition. (Really, we want it to fire at 17 seconds, but we
learned last year that we needed to close the window in the event the
sustainer was off-angle to prevent a misfire during recovery.) In the
eeprom file, the "Ignitor A" event shows up at ~17.2 seconds. However the
"Ignitor A Voltage" shows a brief drop around 15.5 seconds, and no sign of
a drop at the actual event. The other ignitor voltage drops line up with
their events, or immediately after. It seems strange that this one was over
a second early. I can't explain that... We know it burned. Did our wiring
briefly glitch right before?
Also, possibly a minor bug: I don't see the ground r/p/y and aux ignitor
voltages in the csv export. (I should learn java...)
Casey
PS: I made the new avionics bays on a 3D printer. The bay models
themselves probably aren't useful to others, but I do have basic solid-body
STL models of both computers for evaluating fit and screw posts. I'll share
those when I get a chance.
I saw the earlier question and answer in April about the TeleBT being back
in production soon. Do you have any new information about when it will be
available?
I would like to fly a TeleGPS at AirFest on Labor Day weekend, and need to
decide whether to buy one with a TeleDongle now, or wait for the shiny new
TeleBT. Thanks!
Dan Crank
I've uploaded version 1.6.0.3, in preparation to creating a 1.6.1 when
people are happy enough with the code.
Big changes include:
* Offline maps. Download maps for you favorite launch sites and track
without network access
* Map types. Use satellite images, road maps or terrain data to help
locate your rockets
* Voice output now depends on current selected tab. This way, you have
control over what voice information you're getting.
* Track multiple rockets. This remembers every rocket the device has
ever seen and shows them all on the map at once, letting you select
among them for further information.
If you're a member of the AltosMetrum Google+ community, you should
already be able to see the beta version in the play store. Otherwise,
feel free to visit this page:
https://play.google.com/apps/testing/org.altusmetrum.AltosDroid
I've tested the code about as much as I can by myself and am now looking
for people willing to help out with that, and provide feedback about the
new stuff.
--
-keith
Yes,
I have one. The F6A is a nice unit and has the potential of being able to track the
stuff on the 1.25cm band because it can receive in several different modes
on VFO B. (hi-SSB, lo-SSB or CW modes)
Stick an offset attenuator on your YAGI and you're in business.
This one is pretty decent:
http://www.west.net/~marvin/k0ov.htm
You can lookup schematics or other kits too. Alot easier spinning a pot
than changing antennas or what have you.
One needs to keep in mind if one's rocket is lying in an open area, piece 'o cake
to find it via RDF. If it's hiding in tall grass, corn, between hedgerows, in furrows and shallow depressions,
that's when being able to hold an accurate bearing up close will help you.
If you are using a GPS tracker and are able to get this close, you'll be receiving a valid
GPS packet unless there is some malfunction with your tracker or it's not receiving a
vaild lat/long. In that case, if it's hidden, being able to home in via RDF might be useful.
Heck, the open squelch technique is perfectly valid and I use it every time with an APRS tracker.
For a rocket that's down, if one can open the squelch and faintly "hear" a packet that's too distorted to be decoded, viola' they know
immediately the APRS tracker is still working. This is especially reassuring for a flight where there is no visual confirmation
of any of the events. If one sees valid altitudes coming across, they can surmise by the rate of descent reported that the
drogue has deployed and the main made it out. Walk to the last known reported position and likely one will receive
the position of the final resting place if the rocket is not already seen.
This is where GPS tracking really shines on flights where small rockets go "way high", "way fast" and land "way far" away.
Way far away may just be just 1/2 mile. My Wildman Jr., I nor anyone else has ever seen a complete flight on the five J motors
I've flown in it. Every time the rocket disappears I can tell the events have occurred and which direction to try to look for the main chute.
Never seen it under the main but the altitude indications show it's deployed and it looks nice as can be when walking up to it.
One of these days I'll fly it on an I motor to see what is looks like. Oh, I do pop the main at 1000' to increase the chances it's seen.
Kurt KC9LDH
--------------------------------------------
On Wed, 6/17/15, Chris Attebery <chrisattebery1971(a)gmail.com> wrote:
Subject: Re: [altusmetrum] RDF on the cheap
To: "Altus Metrum" <altusmetrum(a)lists.gag.com>
Date: Wednesday, June 17, 2015, 2:02 PM
Do any of
you have experience with the Kenwood TH F6A HT? There are a
couple on ebay for reasonable prices.
I'd suggest shopping the used HT market.
The Baofung (or however it's spelled) radios can be bought cheap, but based on what I've seen of them, they'll make RDF a bit more challenging. I'd suggest investing in a used radio of better quality if you plan to RDF with it.
-Kevin
From: altusmetrum [mailto:altusmetrum-bounces@lists.gag.com] On Behalf Of Chris Attebery
Sent: Monday, June 15, 2015 7:01 PM
To: altusmetrum(a)lists.gag.com
Subject: [altusmetrum] RDF on the cheap
I'd like to be able to RDF my Telemetrum with a low end HT and antenna. Can any of you make a recommendation for a low end radio (<$50)? Also will the Arrow 440-3 work well enough at Black Rock or should I pick up the 440-5? Is there anything else I would need?
Thanks,
Chris
I'd like to be able to RDF my Telemetrum with a low end HT and antenna. Can
any of you make a recommendation for a low end radio (<$50)? Also will the
Arrow 440-3 work well enough at Black Rock or should I pick up the 440-5?
Is there anything else I would need?
Thanks,
Chris
It does. However sometimes packets get garbled, GPS lock can be lost, etc.
Knowing how to perform RDF in such situations can be the difference between recovering your rocket and not.
-Kevin
From: altusmetrum [mailto:altusmetrum-bounces@lists.gag.com] On Behalf Of Winton H. E. Davies
Sent: Monday, June 15, 2015 7:38 PM
To: Altus Metrum
Subject: Re: [altusmetrum] RDF on the cheap
Wait, doesn't the telemetrum do GPS over radio? Why would you need RDF? Just get the dongle and attach to laptop (or even android device I believe now?)
W
On Mon, Jun 15, 2015 at 5:08 PM, Kevin Trojanowski <troj(a)cox.net> wrote:
I'd suggest shopping the used HT market.
The Baofung (or however it's spelled) radios can be bought cheap, but based on what I've seen of them, they'll make RDF a bit more challenging. I'd suggest investing in a used radio of better quality if you plan to RDF with it.
-Kevin
From: altusmetrum [mailto:altusmetrum-bounces@lists.gag.com] On Behalf Of Chris Attebery
Sent: Monday, June 15, 2015 7:01 PM
To: altusmetrum(a)lists.gag.com
Subject: [altusmetrum] RDF on the cheap
I'd like to be able to RDF my Telemetrum with a low end HT and antenna. Can any of you make a recommendation for a low end radio (<$50)? Also will the Arrow 440-3 work well enough at Black Rock or should I pick up the 440-5? Is there anything else I would need?
Thanks,
Chris
_______________________________________________
altusmetrum mailing list
altusmetrum(a)lists.gag.com
http://lists.gag.com/mailman/listinfo/altusmetrum
I noticed that Sparkfun no longer sells the Rayson BTM-182 Blutooth
module, and their replacement part has a different footprint than the
TeleBT PCB. I went to Rayson's site, and they don't list that part
number. Where is a good source for buying 3-4 of these modules?
Best Wishes!
Steve
