At 21:30 26 April 2018, Ben Hirashima wrote:

...
Regarding the frequency goTenna Mesh uses, their FAQ says:

goTenna Mesh will transmit at 1 W on 902-928 MHz in the United
States, and will vary throughout other countries. For example: goTenna
Mesh will transmit at 0.5 W on 869.4-869.65 MHz in Europe and other
CE countries, and the device will auto-tune itself to the appropriate
frequency band and power output based on the location where it's being
used.

In my research on 902-928 MHz in the US, I could not find any
specific prohibition against using the frequency while airborne. I asked
goTenna if the Mesh was legal to use in the air, and they said they didn't

know one way or the other. I did find that the original goTenna uses a
MURS frequency that is not legal to use in the air, but MURS is not used
by the goTenna Mesh.

As far as Europe or other countries go, I haven't yet done any
research on the legality of using the goTenna Mesh in the air. Anyone
know?

...

See IR2030/1/19 for EU or 2014/88/UK June 2014 for UK. Other
countries may have different regulations.

- IR2030/1/19 2014/88/UK June 2014 -
Non-specific short-range devices.

** Equipment may be used airborne.**

869.40 - 869.65 MHz 500 mW e.r.p.

Techniques to access spectrum and mitigate interference that provide at
least equivalent performance to the techniques described in harmonised
standards adopted under Directive 2014/53/EU must be used. This can
include for example Listen Before Talk. Alternatively a duty cycle limit of

10% may be used.
EN 300 220 2013/752/EU Band No.54b.
...

Don't you love bureaucratic language! "Let's make sure the 'plebs'
don't understand and then fine them thousands of £/$ for infraction"!

The GoTenna limit of five messages per minute probably equates to the
maximum 10% duty-cycle for the protocol that they have chosen.
FLARM at ~868 Mhz limit their transmission to a very short data burst
at 10mW once per second - much less than required but adequate for
the their purpose.

The GoTenna (sounds like Lady Tena:-) map -
https://www.imeshyou.com/ indicates a good cluster in UK but sparse
population in Europe. I assume these ground stations (mostly mobile
and not 24/7) in non-gliding areas [cities] and not always active) could
relay signals between gliders and other traffic?

All five of my small, UK club gliders and most of our 20+ private gliders
have basic FLARM (£700, no ADS-B). Whilst your app may be more cost
effective than FLARM it requires an Android 'phone and has no collision
avoidance algorithm. I expect little take-up in Europe except for glider
pilots who already have a GoTenna and an Android 'phone.

OTOH, a network of GoTenna ground stations could provide better
coverage than OGN.

Good luck with your excellent project!

Alan (UK)