TeleMetrum GPS

[jaz]

Just put my order in for the TeleMetrum GPS. Its for my level 3 rocket so as soon as I receive it I will give my review of it. I am looking forward to not having to use my Romeo puppod for gps tracking.

 

[jaz]

I got my gps yesterday and got around to playing with it. It really is small not much different than my ha45 in terms of size. The circuit board is very dense with surface components and all the cable connections are very tight.
The main monitoring software is easy to install using the file provided.
I am using a windows XP laptop and I tried it as well on my Vista desktop. The only thing I needed to find was a terminal program to utilize the radio link. Once I got that it is pretty simple to communicate with altimeter from my laptop. The one thing that would be nice is a consolidated list of all the terminal commands.

This is a very nice product and I feel with a couple of test flights it will go on my level 3 rocket. I wouldn't recommend it as a first altimeter since you need to practice to get things connected and order does matter but I am excited about this product.

If anyone has any questions please let me know.

 

[Blackfly]

A few questions:

1) what happens when you're armed on the pad and you lose GPS?

2) If you lose the uplink signal, does it go to failsafe or reset?

 

[jaz]

If it loses gps lock it will seek for a signal but the altimeter functions and radio link are unaffected. If I lose the radio link nothing happens to the altimeter functions. The radio and gps are like the extras so it is independent of the functions of the altimeter. You can reset via the radio link but you must do it using the terminal program. Hopes this helps. I am test flying hopefully next weekend and also going to try the ground test function on the ejection charges.

 

[bobkrech]

A few questions:

1) what happens when you're armed on the pad and you lose GPS?

2) If you lose the uplink signal, does it go to failsafe or reset?

You probably won't loose GPS lock simply sitting on the pad unless less than 3 satellites are in view, but you will loose lock while the motor is thrusting since most commercial GPS chip loose lock somewhere between 4 G to 6G acceleration. It then takes a second or so for the GPS to find itself again.

Bob

 

[sandmantoy]

What terminal program did you use. I am interested in this subject but will admit I don't how it works yet. I have read about the TeleMetrum GPS. I would like to learn more about it. Looks like a nice unit.

 

[jaz]

There is a pay version with a 30 day free trial call hilgraeve hyper terminal private edition. There is also a way to add hyper terminal back to windows here is a link that talks about it.
https://digitizor.com/2009/08/29/ho...al-client-on-windows-vista-or-windows-7-free/

BTW got to play around with the ground test function this weekend and it is fun to get altimeter status updates and functions via a radio link. It is simple to use but practice is must to get a hang of the routine.

 

[bdale]

The main monitoring software is easy to install using the file provided.
I am using a windows XP laptop and I tried it as well on my Vista desktop. The only thing I needed to find was a terminal program to utilize the radio link. Once I got that it is pretty simple to communicate with altimeter from my laptop. The one thing that would be nice is a consolidated list of all the terminal commands.

Hi! If you haven't already discovered it, please note that freshest software is always available from https://altusmetrum.org/AltOS. The current production release is 0.7.1, but we'll be rolling to 0.7.2 shortly. The new features in 0.7.2 include in-built data plotting with zoom and export of KML for use with Google Earth (the latter is available in the first generation C code but only recently got ported into the Java code, with several improvements). There are no firmware changes between 0.7.1 and 0.7.2, just more functionality in the ground software.

We're getting close to eliminating the need for a terminal program, as most things can now be done from AltosUI. Feel free to let me know what else you'd like the software to do.

And yes, I know the docs could use another update. Hope to get to that soon!

 

[bdale]

1) what happens when you're armed on the pad and you lose GPS?

The current ground software doesn't indicate ready for flight until you've had GPS lock for at least 10 seconds. If you lose GPS lock on the rail, the ground software changes state back to waiting for lock. This has no effect on the operation of the firmware, it will detect launch and trigger ejection events and so forth in flight whether it has GPS lock or not.

2) If you lose the uplink signal, does it go to failsafe or reset?

The TeleMetrum board only listens to the radio in 'idle' mode, once it's in 'flight' mode it operates transmit-only.

 

[jaz]

Looking forward to the software update thanks for your hard work. It really isn't that hard to get up and running and it really is a cool piece of gear.

 

[jaz]

Any updates on the 0.7.2 release?

 

[bdale]

Any updates on the 0.7.2 release?

It took a little longer than expected, and in the end enough had changed that we decided to call it 0.8 instead of 0.7.2, but the bits are out now! This is a significant update with a new look to the ground station software, and lots of new features. Hope you enjoy it!

More details at https://www.altusmetrum.org/AltOS/.

 

[jaz]

Thanks
I love the product and cant wait to try out the update!

 

[sandmantoy]

Excellent to see this product moving forward! I don't think it needs such a small foot print as I would be using it in larger rockets and with more room for multiple batteries if needed. There seem to be plenty of small units out there. 4" and larger rockets have a lot more room for electronics and seem to go much farther from the pad when being recovered sometimes.

I am interested in seeing what type amplified antennas can be added to it and how also.

 

[n5wd]

I don't think it needs such a small foot print as I would be using it in larger rockets and with more room for multiple batteries if needed. There seem to be plenty of small units out there. 4" and larger rockets have a lot more room for electronics and seem to go much farther from the pad when being recovered sometimes.

Dude, just 'cuz you've got room in your 4" rocket doesn't mean that everyone else that might be using the Telemetrum device would too! Small doesn't hurt those with more room available (unless you've got paws that can't candle the small board), but bigger footprints make it impossible for a lot of others to use it as they want. Size is fine as it is.

I am interested in seeing what type amplified antennas can be added to it and how also.

Again, huh? An amplified antenna might be useful for your TV, but isn't really the way most RF systems work - if you need more signal, use an antenna with more gain (i.e. go to a 3 el beam from your quarter-wave spike - go to a 7 el-beam from your 3-el yagi, etc.). Bdale would have to tell us whether the spectral purity of the transmitter could handle an amp hung onto the transmitter in the rocket, but I wouldn't hold my breath on that happening (the amp, not Bdale telling us) :blush:

 

[sandmantoy]

Dude, just 'cuz you've got room in your 4" rocket doesn't mean that everyone else that might be using the Telemetrum device would too! Small doesn't hurt those with more room available (unless you've got paws that can't candle the small board), but bigger footprints make it impossible for a lot of others to use it as they want. Size is fine as it is.



Again, huh? An amplified antenna might be useful for your TV, but isn't really the way most RF systems work - if you need more signal, use an antenna with more gain (i.e. go to a 3 el beam from your quarter-wave spike - go to a 7 el-beam from your 3-el yagi, etc.). Bdale would have to tell us whether the spectral purity of the transmitter could handle an amp hung onto the transmitter in the rocket, but I wouldn't hold my breath on that happening (the amp, not Bdale telling us) :blush:

LOL! Might be the paws. I don't think my one comment on size was going to change things anyway. How far do your little rockets land anyway, Mine don't seem to go far enough to bother with GPS but the big ones sometimes do.

Amplified antenna was the wrong choice on my part and more gain would have been a better description of what I meant. On the website it says you can put different antennas on the unit, I was wondering how. I don't hide the fact that I not an expert on the subject hence the questions. If that's ok to do in here but thanks for getting me on tract

 

[bdale]

Bdale would have to tell us whether the spectral purity of the transmitter could handle an amp hung onto the transmitter in the rocket, but I wouldn't hold my breath on that happening (the amp, not Bdale telling us) :blush:

It's pretty good, but the couple times I've pondered optional amplifiers, I've just assumed that I'd design in some suitable filtering. But so far, every time I've run the numbers, more power on the rocket end of the radio link just hasn't seemed like the right way to improve the link margin. More antenna gain on the ground, and/or getting a tracking station or two away from the launch rail better positioned in the radiation pattern during boost and/or down-range in the path of most likely recovery seem like the big wins to me.

 

[bdale]

LOL! How far do your little rockets land anyway, Mine don't seem to go far enough to bother with GPS but the big ones sometimes do.

My experience is almost exactly the opposite. My big rockets are usually possible to track visually, and/or are pretty easy to find after they touch down. On the other hand, my minimum diameter and near-minimum diameter rockets are often completely invisible after the boost related smoke trail ends... unless someone happens to spot a puff at apogee.

For example, the last time I was out, I put a 54mm airframe up to a bit over 7700 feet, had a "main out at apogee" oops, and was still able to find the airframe a little over 2.25 miles down range in tall weeds in the side yard of someone's residential property... *only* because I had a GPS fix on it until it was nearly down, and the ability to RDF it once I was in the right neighborhood.

Amplified antenna was the wrong choice on my part and more gain would have been a better description of what I meant. On the website it says you can put different antennas on the unit, I was wondering how. I don't hide the fact that I not an expert on the subject hence the questions. If that's ok to do in here but thanks for getting me on tract

On TeleMetrum, we put a 1/4 wave wire whip on for the UHF antenna by default, but the board is laid out to allow you to replace that with an SMA connector if you want, which means you can cable up any sort of 70cm antenna you feel like on the rocket end.

For the GPS, we include an amplified patch on the board, that plugs in via a U.FL connector. If you want/need a remote GPS antenna, you can unplug the one that's built in and plug something remote in that has a matching connector quite easily.

 

[sandmantoy]

We had a 8" rocket put the main out and it was many hours to recover it. I don't remember the altitude but once it is out of site it's a long hunt and you miss a lot of launches by the time you get back. Wooded areas have no mercy on any size rocket. I do like the option to put different antennas on.