[wizardgmb]

I'm spending entirely too much time on this topic but it is what it is.

I called the ARRL and they didn't have much to say because the arduino transmitters aren't ham radio items. Was also told that arduino transmitter modules did not need FCC type acceptance because it is not a finished product, it is simply a part intended to be used with a collection of parts. He also mentioned there are regulatory provisions for hobbyists, which is what I remembered reading previously. Googling that further I found the following which hopefully will put this topic to rest, at least for those of us in the USA.

Part 15.23

Home-Built Transmitters that are Not for Sale

Hobbyists, inventors and other parties that design and build Part 15 transmitters with
no intention of ever marketing them may construct and operate up to five such
transmitters for their own personal use without having to obtain FCC equipment
authorization. If possible, these transmitters should be tested for compliance with the
Commission's rules. If such testing is not practicable, their designers and builders are
required to employ good engineering practices in order to ensure compliance with the
Part 15 standards.

These can be used between 410-470MHz with emissions limits, however, testing is not required as per Part 15.23 but good engineering practices should be employed,with the all encompassing caveat that it may not create interference and must accept interference.

So to summarize. In the USA you can use up to 5 unlicensed non-type accepted transmitters for your own personal use as long as you aren't selling them. And if you're that concerned about emissions limits (that anyone still curious is welcome to google for themselves) then feel free to spend the thousands of dollars required to comply with something you're not expected to test for anyway.

I'm sorry for being late to followup but I couldn't leave it to rest.

This Part 15 section in addition to your Part 15 quotation is very enlightening:

15.203 An intentional radiator shall be designed to ensure that no antenna other than that furnished by the responsible party shall be used with the device. The use of a permanently attached antenna or of an antenna that uses a unique coupling to the intentional radiator shall be considered sufficient to comply with the provisions of this section. The manufacturer may design the unit so that a broken antenna can be replaced by the user, but the use of a standard antenna jack or electrical connector is prohibited.

The WeatherDuino has the transmitter output connected to a SMA female connector and the mating SMA male connector is definitely standard and very readily available. Therefore the WeatherDuino design fails to meet FCC Part 15 requirements and the hobbyist has failed to meet the requirement for "good engineering practices in order to ensure compliance with the Part 15 standards" . Anyone could connect an amateur radio 70cm base station antenna with 6dBi gain to a WeatherDuino, knock out shipping container operations a mile away and probably piss off a few amateurs.

From the FCC document Understanding the FCC Regulations for Low-Power Non-Licensed Transmitters:

https://transition.fcc.gov/Bureaus/Engin...t63rev.pdf

"Home-built transmitters, like all Part 15 transmitters, are not allowed to cause interference to licensed radio communications and must accept any interference they receive. If a home-built Part 15 transmitter does cause interference to licensed radio communications, the Commission (FCC) will require its operator to cease operation until the interference problem is corrected. Furthermore, if the Commission (FCC) determines the operator of such a transmitter has not attempted to ensure compliance with the Part 15 technical standards by employing good engineering practices then that operator may be fined up to $10,000 for each violation and $75,000 for a repeat or continuing violation."

I have FCC amateur and commercial licenses, years of experience and a bench full of equipment to ensure transmissions from my future WeatherDuino meets the the Part 15 requirements (if I don't use it at 433 MHz as an amateur) even if the SMA connector doesn't. You may also have the prerequisites but we are probably among the minority. If one's WeatherDuino isn't built or operated properly or isn't stable there are two possibilities based upon frequency: pissing off a nearby shipping company or amateur radio operator on 433 MHz or having some non-knowledgeable neighbors using 315 MHz remote controls that can't unlock their cars or open their garage doors on the first try. I think the latter is a better choice for WeatherDuino owners in the USA, the chances of getting drawn & quartered by the FCC are much lower on 315 MHz.

Regards,
George