[PragmaticPulp]

Clever hack, but a lot of people are misinterpreting what’s going on here. These devices emit some very low level of 125MHz energy during normal operation. This software is simply turning that on and off, but not doing anything to increase the amount of emissions.

Presumably the 125MHz emissions are within the FCC allowed envelope anyway, so this isn’t doing anything to exceed normal emissions limits. This only works in a quiet RF environment, as noted in the README.

There is no need to be concerned about this signal reaching aircraft or otherwise interfering with normal transmissions.

[jcrawfordor]

Aviation radios on aircraft are typically 25w and ground stations the same to somewhat higher... and operations are generally line of sight and using analog AM modulation, which gets along nicely with CW. From a practical perspective (rather than regulatory), it is difficult to imagine miliwatt CW transmissions causing any meaningful problem with aircraft operations. Most radio systems used on aircraft are not really all that sensitive anyway, the most touchy thing would be the glideslope/localizer but it's only used at fairly short ranges and with fairly high power levels. This could perhaps cause a slight deflection of the ILS but that's assuming it's very close to the runway and at high power. This paper discusses security of the ILS system against tampering, which is generally the most "touchy" thing that aircraft use and the main interference concern: https://www.usenix.org/system/files/sec19-sathaye.pdf

That's all sort of besides the point anyway as nav aids use the lower end of the aviation band, 125MHz is used for AM voice where the interference would be, at worst, audible but not strong enough to cause problems unless reception was already extremely marginal.

Or to put it differently, two pilots hitting their PTT at the same time is already causing far more disruption to operations in the 125MHz range than this thing ever would.

[tyingq]

125Mhz is the frequency you get with 100 base tx. It's basically the baud rate of 100mb plus the 5 bits to encode 4 bits overhead. 100 * 5/4 = 125.

As you mention, this is toggling the expected 125Mhz on and off. It's not noise, it's "the signal".

[jdietrich]

>Presumably the 125MHz emissions are within the FCC allowed envelope anyway, so this isn’t doing anything to exceed normal emissions limits.

From a regulatory perspective, there's a big difference between intentional and unintentional radiators.