As others have said, during flight, eyes are up, so map is not important, but audio velocity and altitude would be nice... But at apogee and deployed, then pointer, bearing and map would be very beneficial. Here in Utah our two sites are flat, Bonneville salt flats, the other has dried creek beds and sage brush that rockets could get lost in, so having a map to see where it is would be very beneficial to planning route to rocket. Having to backtrack due to a steep inclined creek bed sucks.
Waiting to buy the GPS units so I can link it with the software and continue to use it. Hellfire is coming up, and would love to try it out on the salt flats! No cert flights planned, but want to put it in a variety of other rockets and see how it performs.
Kurt,
Just FYI, I've been going to the playa since 2010. I've recovered rockets as far as 4.5 miles away with nothing more than a simple RDF tracker (an old rocket hunter system I bought shortly after I first started flying.) I have only ever used RDF recovery at BALLS (with multiple flights over 20,000') and have never lost a rocket there. And using regular FRS radios we get pretty much the same range as is typical. Plus Adrian has already tracked a rocket to over 100,000 feet at BALLS on the Playa using his system.
Tony
The only additional feature I would like is for the app to scream bloody murder if the rocket is coming in ballistic. Don't make my brain have to process the rapid decent, but let me set some threshold like 250 fps (after apogee of course) ahead of time (or have it hard set) to trigger the warning. My apologies if this has already been covered.
That, and availability...take my money!!!!!!!!
I take it that the Featherweight reports altitude?:wink: Here's what you do, keep in mind the expected update rate of the tracker and watch the altitude descent rate. Keep in mind that perhaps not every position will be properly decoded
although Adrian reported that this device recovers ~90% or greater positions. There is going to be a range limit out there and I suspect it's going to be pretty far with this device. Basically, the closer the rocket is to the receive station, the lower the last position and altitude is going to be reported. The farther away, the last known position and altitude (holding the power output the same) will be higher up in the air.
With the Featherweight there would be the additional step of inputting the lat/long into another mapping device/app but that's no big deal as long as one is adept at transferring data. Keep in mind with a ballistic flight the tracker is going to die in the process so that last position "up in the air" is critical to get to the spot. On the other hand
the rocket is coming in hot so the hole is not too far away from that reported position in the air.
It's actually a lot more straightforward than that. The GPS chip outputs 3D velocity information (it's really accurate from what I have seen) and we're reporting the horizontal and vertical velocity real-time in the app.
Vertical velocity the main thing I watch real-time, because you can tell whether the apogee ejection and main deployments worked. Good idea about highlighting visually and probably audibly if the vertical velocity gets too fast.
Most people now are just using the real-time pointing to walk up to their rocket. The Featherweight GPS stores the last valid data, so even if it comes in ballistic, you can still follow the directions right to the hole. (or crater, in the case of a 137,000 foot flight at BALLS with a failed deployment)
That is fantastic. I can only see horizontal velocity and a scrolling altitude, not vertical velocity on the apps I'm confined to use currently. Do tell, is the vertical velocity with the GPS constrained by treaty also or is that horizontal velocity only?
Looking forward to it.
Are you able to post any specs on the transmission frequency/power so I can look into the Australian regulations?
I will hold a HAM license in July which avoids most of the limitations.
It's a non-HAM band, 915 MHz.
In Australia there might be some different frequency requirements, even though it's on the non licensed band in the USA.Twobit might
be able to comment. Kurt
Yes, the frequency for the dedicated comm to/from your own ground station will be user-selectable over a wide range. I have been planning to have some special-purpose fixed-frequency public channels as well, and I understand that for you guys down under you would need those to be in 915-928 MHz range as well.
The LIPD class license for the ISM band in Australia for the "900MHz" band starts at 918MHZ, not 915MHz like a lot of other places in the world. Australian units are required to not transmit below 918MHz, so as to not interfere with Telco services.
As a rule I make sure I transmit on 919MHz or higher if I am using that band, to ensure a sufficient buffer so I don't end up with any significant out-of-band emissions.
https://www.acma.gov.au/Industry/Sp...ass-licences/lipd-class-licence-spectrum-acma
I could probably create a virtual 'box' around Australia so the frequencies outside the allowed range are not available.
I could probably create a virtual 'box' around Australia so the frequencies outside the allowed range are not available.
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