4 ms·
The harmonics are above the transmission frequency, so a low pass filter is normally all that is needed to clean this up. There is a project that uses a Raspb
by jimnotgym 8y ago
The harmonics are above the transmission frequency, so a low pass filter is normally all that is needed to clean this up.
There is a project that uses a Raspberry pi to transmit from is GPIO
To use a home built transmitter you need amateur radio license, no matter what.
- vvanders 8y agoOnly for amateur bands. ISM, 2.4Ghz and 5Ghz along with a few others don't require a license.
- wglb 8y agoNot true. Low power FM and AM stations are allowed. https://www.fcc.gov/media/radio/low-power-radio-general-information https://www.fcc.gov/media/radio/low-power-radio-general-info...
- lima 8y agoAnd there's ISM bands as well. However, all of these unlicensed bands have strict limits. For any of the fun stuff, you need an amateur radio license :-)
- andyidsinga 8y ago> However, all of these unlicensed bands have strict limits. This is absolutely key here - even in unlicensed bands one cannot just start using the spectrum without careful consideration of regulations for that spectrum. When I was working in the 902-928 Mhz (FCC and similar) and 860s (for ETSI) for RFID we had to do a lot of work to ensure our transmit power, power ramp up, frequency hopping and listen before talk were all implemented properly and demonstrable for certification. It was not trivial.
- jimnotgym 8y agoI got called away while writing this earlier and rushed my last point which is clearly wrong. It is too late to edit. Instead: To use a home built transmitter you need amateur radio license, except in certain specific low power situations. To comply with those situations would be difficult without specialised test gear.