Since neither the description on Massdrop nor the GreatScottGadgets page made any reference to transmit power, I looked at the schematics and this is what I came up with:
- 10 dBm output from the CC1110, which is 10 milliwatts at 50 ohms.
- That's passed to a SPF5043Z LNA MMIC, which has a ~18 dB gain
- There would be a bit of loss in the SKY13385 switch and the LPF but let's just say they're negligable.
- That totals out to a whopping 631 milliwatts of output
tl;dr: This is keyfob territory, not amatuer radio station territory. e.g. within a building or within the range of a car. Being that this radio will happily transmit in amateur radio 70cm band, it could be hooked up to a linear amplifier up to the legal limit (1500W, IIRC) as long as it's within the geographical limitations, e.g. stay the heck away from Canada). You'd need some sort of power-activated PTT but otherwise would work. There are better 70cm radios out there, considering this one only works with a few select data modes (admittedly at 500 kbps which isn't shabby).
Edit: I only briefly looked at this, if anyone comes up with a different number, I'll be happy to edit my post.