## PCB Weight ##

The density of FR4 is 1,850 kg/m^3. If we assume a PCB area of 12*50 =
600 mm^2...

For a 1.0mm PCB: 600 * 1.0 * 1.85 = 1.110g
For a 1.6mm PCB: 600 * 1.6 * 1.85 = 1.728g

## Contestia ##

There doesn't appear to be much documentation for contestia...

[Oh here's some](http://f1ult.free.fr/DIGIMODES/MULTIPSK/contestia_rttym_en.htm)

Really we're looking at Olivia MFSK - contestia is just a variant.

[Wikipedia](http://en.wikipedia.org/wiki/Olivia_MFSK)
[ARRL](http://www.arrl.org/olivia)

It's already implemented in dl-fldigi [here](https://github.com/jamescoxon/dl-fldigi/blob/master/src/include/jalocha/pj_mfsk.h)

(Inverse) Fast Hadamard Transform needed


## APRS ##

[some description..](http://dooce.de/dokuwiki/doku.php?id=projekte:utrak:aprs)