# Using Altus Metrum Products

## Being Legal ##

First off, in the US, you need an [amateur radio license](../Radio) or 
other authorization to legally operate the radio transmitters that are part
of our products.

## In the Rocket ##

In the rocket itself, you just need a [TeleMetrum](../TeleMetrum) board and 
a LiPo rechargeable battery.  An 860mAh battery weighs less than a 9V 
alkaline battery, and will run a [TeleMetrum](../TeleMetrum) for hours.

By default, we ship TeleMetrum with a simple wire antenna.  If your 
electronics bay or the airframe it resides within is made of carbon fiber, 
which is opaque to RF signals, you may choose to have an SMA connector 
installed so that you can run a coaxial cable to an antenna mounted 
elsewhere in the rocket.

## On the Ground ##

To receive the data stream from the rocket, you need an antenna and short 
feedline connected to one of our [TeleDongle](../TeleDongle) units.  The
TeleDongle in turn plugs directly into the USB port on a notebook 
computer.  Because TeleDongle looks like a simple serial port, your computer
does not require special device drivers... just plug it in.

Right now, all of our application software is written for Linux.  However, 
because we understand that many people run Windows or MacOS, we are working 
on a new ground station program written in Java that should work on all
operating systems.

After the flight, you can use the RF link to extract the more detailed data 
logged in the rocket, or you can use a mini USB cable to plug into the 
TeleMetrum board directly.  Pulling out the data without having to open up
the rocket is pretty cool!  A USB cable is also how you charge the LiPo 
battery, so you'll want one of those anyway... the same cable used by lots 
of digital cameras and other modern electronic stuff will work fine.

If your rocket lands out of sight, you may enjoy having a hand-held GPS 
receiver, so that you can put in a waypoint for the last reported rocket 
position before touch-down.  This makes looking for your rocket a lot like 
Geo-Cacheing... just go to the waypoint and look around starting from there.

You may also enjoy having a ham radio "HT" that covers the 70cm band... you 
can use that with your antenna to direction-find the rocket on the ground 
the same way you can use a Walston or Beeline tracker.  This can be handy 
if the rocket is hiding in sage brush or a tree, or if the last GPS position 
doesn't get you close enough because the rocket dropped into a canyon, or 
the wind is blowing it across a dry lake bed, or something like that...  Keith
and Bdale both currently own and use the 
[Yaesu VX-6R](http://yaesu.com/indexVS.cfm?cmd=DisplayProducts&ProdCatID=111&encProdID=4C6F204F6FEBB5BAFA58BCC1C131EAC0&DivisionID=65&isArchived=0) 
at launches.

So, to recap, on the ground the hardware you'll need includes:

* an antenna and feedline
* a TeleDongle
* a notebook computer
* optionally, a handheld GPS receiver
* optionally, an HT or receiver covering 435 Mhz

The best hand-held commercial directional antennas we've found for radio 
direction finding rockets are from 
[Arrow Antennas](http://www.arrowantennas.com/).  The 440-3 and 440-5 are 
both good choices for finding a TeleMetrum-equipped rocket when used with 
a suitable 70cm HT.  

Find more information about antennas, HTs, and getting a ham radio license
on our [Radio](../Radio) page.

## Data Analysis ##

Our software makes it easy to log the data from each flight, both the 
telemetry received over the RF link during the flight itself, and the more
complete data log recorded in the DataFlash memory on the TeleMetrum 
board.  Once this data is on your computer, our postflight tools make it
easy to view a standard set of plots showing the altitude, acceleration, and
velocity of the rocket during flight.  You can also export a data file useable
with Google Maps and Google Earth for visualizing the flight path in two or
three dimensions.

Our ultimate goal is to emit a set of files for each flight that can be
published as a web page per flight, or just viewed on your local disk with 
a web browser.

## Future Plans ##

In the future, we intend to offer "companion boards" for the rocket that will
plug in to TeleMetrum to collect additional data, provide more pyro channels,
and so forth.  A reference design for a companion board will be documented
soon, and will be compatible with open source Arduino programming tools.

We are also working on the design of a hand-held ground terminal that will
allow monitoring the rocket's status, collecting data during flight, and
logging data after flight without the need for a notebook computer on the
flight line.  Particularly since it is so difficult to read most notebook
screens in direct sunlight, we think this will be a great thing to have.