Many commercially available drones operate at 2.4 GHz / 5.8 GHz. This is covered under part 15. General rule of thumb if they operate at less than half a watt, no license is required. The same is not true for the drones that are operating at 400 MHz. For more information about licensing contact dave@landmobile.com
Below is information regarding part 15 drones. (Its important to note that these unmanned vehicles will need to be cleared with the FAA - stayed tuned for FAA drone registration article)FCC Rules for Unlicensed Wireless Equipment
The ISM radio bands were originally set aside for electromagnetic radiation produced by industrial, scientific and medical (ISM) equipment. In the early 1990's the Federal Communcations Commission (FCC) allowed using three of the ISM bands for unlicensed communication equipment. These three ISM bands are:- 902 to 928 MHz
- 2.400 to 2.4835 GHz
- 5.725 to 5.875 GHz
Maximum Transmit Output Power in the ISM bands
Several of the FCC part 15 rules govern the transmit power permitted in the ISM bands. Here is a summary of those rules:-
Maximum transmitter output power, fed into the antenna, is 30 dBm (1 watt).
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Maximum Effective Isotropic Radiated Power (EIRP) is 36 dBm (4 watt).
You can obtain the EIRP by simply adding the transmit output power, in dBm, to the antenna gain in dBi (if there is loss in the cable feeding the antenna you may subtract that loss).
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If your equipment is used in a fixed point-to-point link, there are two exceptions to the maximum EIRP rule above:
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In the 5.8 GHz band the rule is less restrictive. The maximum EIRP allowed is 53 dBm (30 dBm plus 23 dBi of antenna gain).
- In the 2.4 GHz band you can increase the antenna gain to get an EIRP above 36 dBm but for every 3dBi increase of antenna gain you must reduce the transmit power by 1 dBm. The table below shows the combinations of allowed transmit power / antenna gain and the resulting EIRP.
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In the 5.8 GHz band the rule is less restrictive. The maximum EIRP allowed is 53 dBm (30 dBm plus 23 dBi of antenna gain).
| Transmit Power (dBm) |
Antenna Gain (dBi) |
EIRP (dBm) |
| 30 | 6 | 36 |
| 29 | 9 | 38 |
| 28 | 12 | 40 |
| 27 | 15 | 42 |
| 26 | 18 | 44 |
| 25 | 21 | 46 |
| 24 | 24 | 48 |
| 23 | 27 | 50 |
| 22 | 30 | 52 |
The FCC regulates not only the "intentional radiation" of radio transmitters, but also the "unintentional radiation" of noise from all sorts of electrical equipment. The FCC regulations appear under part 15. The rules that affect operation of communication equipment in the ISM bands are listed below:
| FCC 15.107 | Conducted Emissions including AC Line |
| FCC 15.109 | Unintentional radiation from ITE |
| FCC 15.205 | Restricted bands of operation |
| FCC 15.207 | Conducted emissions from intentional radiators |
| FCC 15.209 | Radiated emission limits, general requirements |
| FCC 15.247 | ISM Band Communication Equipment |
