I am involved in a precise positioning project that uses Real Time Kinematic (RTK) for cm-accurate positioning. We use unattended base stations that provide real-time corrections for mobile rovers. The corrections can be used within a radius of about 10-20 km around a single base station (rover positioning precision degrades with greater radius) and need a data feed of about 1 kB/s. Currently mainly mobile networks (GSM, 3G, LTE) or ISM bands are used to transmit the corrections.

My question is whether ham radio could be potentially used to transmit RTK corrections from either temporary or permanent base station(s) for non-commercial purposes. The RTK corrections would be publicly available for anyone to use with an unlimited number of rovers in given area. Multiple overlapping base stations could be used for greater area coverage.

Should ham allow the broadcasting I think this may expand globally since 1) it would be very useful public service, 2) receiver equipment would most likely be cheaper (no GSM data etc.) and 3) the range and reliability would be greater than with ISM.

The territories of interest are mainly US and EU (but others welcome too). Of course proper amateur radio licenses would be obtained for broadcasting. The frequency and power used has not been defined yet but should allow for a reliable NLOS propagation.

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    $\begingroup$ This would depend to a large degree on where you are and under which government you'd be getting a license. In the US, I don't think there would be a problem with a beacon station (en.wikipedia.org/wiki/Radio_propagation_beacon) transmitting additional noncommercial data such as position information. $\endgroup$ – user3486184 Apr 11 '16 at 22:14

The only precedent that I can think of for using the ham bands for data beacons, where the data has nothing to do with either ham radio or emergency traffic, is weather station data over APRS. In that case the data is in very short infrequent bursts, and is just being relayed to an internet gateway, rather than being broadcast for general consumption.

You didn't mention what country you're in, but I'll assume that you're in the US, and the rest of my answer is relevant only for that country. I'm not a lawyer, but I can read Part 97. §97.3 defines a beacon as "An amateur station transmitting communications for the purposes of observation of propagation and reception or other related experimental activities," and broadcasting as "transmissions intended for reception by the general public, either direct or relayed." It seems to me that you're talking about a beacon broadcasting data for the general public, rather than to study radio propagation, and so my non-expert take is that what you propose would not be legal.

  • $\begingroup$ Thanks for an answer! There is an interesting post about telemetry where answers seems to endorse it - is that different than what I want to do or are the answers wrong? Seems to me both cases are quite similar... $\endgroup$ – Kozuch Apr 11 '16 at 23:17
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    $\begingroup$ You're welcome! I would argue that the answers you mention are wrong, at least in the US. But then again, according to my interpretation APRS stations sending weather data would be illegal also; I'm not sure if I'm wrong, or if those APRS weather stations are illegal but not worth the FCC's time to prosecute, ha ha. $\endgroup$ – rclocher3 Apr 11 '16 at 23:47
  • $\begingroup$ I see nothing illegal. He can set up beacon far ham radio use, and he cannot prevent everyone else to listen to it. It's like any other ham radio beacon. $\endgroup$ – Pedja YT9TP Mar 15 at 20:46
  • $\begingroup$ @PedjaYT9TP By that logic, one could set up a broadcast station and argue that it's just a beacon. I still think it would be illegal in the US---but I'm no lawyer. $\endgroup$ – rclocher3 Mar 18 at 13:27
  • $\begingroup$ @YT1SG not quiite. Broadcast station emits content that is not allowed for ham radio. emiting content that has some usage for hams cannot be wrong even if it is interesting for larger audience. $\endgroup$ – Pedja YT9TP Mar 19 at 19:39

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