I would like to experiment with amplifiers and larger antennas, and possibly with using the 433MHz radios in the US.
I have an amateur radio license here in the US.
Is there a way to insert call sign information into the data being exchanged by the radios? Perhaps by changing the device ID to your call sign or something of the sort?
It would be awesome if you could just open up Mission Planner and type in your call sign in a box and then save it to the radios and have them transmit it with every data packet.
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There is provision for a user defined serial number in the Mission Planner.
Don't know if it is part of the regular data envelope though, just stored on the AP for users reference.
Could be used to store the Call sign and interrogated I suppose
Sorry, I realize this is a stale thread, but has there been any progress on this? The only other thread I've found with reference to this subject matter was consumed in a fight over appropriate use of GPLicensing.
Well...
I have been giving this some thought. If you use a more powerful ground radio that would require an amateur radio license, it could conceivably fall under the telecommand part 97 rule and you could simply put your call sign label on the transmitter. By using a high gain directional antenna on the ground station, along with a receiver preamp, you could get increased range to the air radio. As long as the air radio is just a stock, part 15 compliant device, it might be a workable strategy for increased range.
Unfortunately, without a way to insert your call sign into the data coming from the air radio, it can't be considered "telecommand" since the air radio isn't sending command instructions like the ground radio, it's only transmitting "telemetry", which would require a regular call sign if the part 15 radiated power levels are exceeded.
Following the MAVLink path, looks like some work has already been done in this area with the Minim-OSD module. This is primarily for use with a video feed. This is an add-on extras to the basic fw. Don't know much other than what I've read so far. Will probably pickup a minim-osd module from ebay (<$10) to try.
See, https://code.google.com/p/minimosd-extra/issues/detail?id=18
On the minimosd, the call sign is entered using the configuration program and stored in the the OSD.
It doesn't get the info from MAVlink messages.
My question was, would it satisfy the FCC requirement for call sign.
I think getting a new MAVlink message added to the APM and entering it with the mission planner is far easier then updating the firmware in the radios.
The call-sign that the minim-osd provides should satisfy FCC requirements if you were transmitting video and data on a regulated ATV frequency.
It probably won't cover us if we were transmitting data using a data modem is on a different frequency (than the ATV feed) or if we are using just a data modem/transceiver without the video feed. Just my $.02.
Agreed.
But I am specifically looking to use 433Mhz telemetry radios in the USA, independent of video. The reason for this is that since the 70cm band is a common, popular amateur radio band, there are tons of great, readily available antenna options, and a host of DIY antenna plans for this band. You can find 900MHz antennae as well, but they are not nearly as numerous as the 70cm band, and there are even fewer DIY plans for yagis and other high gain directional designs as for 70cm.
For FPV flying and simple telemetry like voltage, current, etc. the video transmitter with callsign would be sufficient.
If you want to use a ground station and higher power or 433MHz in the US, then there needs to be a way for the call sign to be inserted into the data itself.
The kluge I was doing for my rocketry might be still a solution here for APM. On the drone end, one could use an arduino mini with a program to append a call-sign with every sentence or packet and on the receiving end, another arduino mini to strip off call-sign header before feeding it to whatever you use to monitor telemetry.
Not eloquent, but probably no worst performance wise than what the minim-osd routines are doing.
BTW - I use a 70cm egg-beater omni to receive telemetry from my rockets.
Easier for the end user or for the developer?
The issue with it being a MAVLink message is that the call sign must be transmitted at least every ten minutes and at the end of communications. Packet radio inserts the call sign into every packet. If it is in a message that is followed by some other telemetry, and then you cut power, the call sign would not be transmitted at the end of communications.
Updating firmware in the radios using Mission Planner is easy. I don't know how easy coding new firmware might be, or changing Mission Planner to work with it.
The OSD would only satisfy station ID for the video transmitter, not the telemetry radio.
I was just looking at the code for the radios, looks like this is a area that might be able to insert a MAVlink message from the radio itself.
It sends it's own messages for RSSI and noise both from the local and remote.
Looks like Tridgell wrote the code for it. Looks like this code hasn't been touched for over a year, and most likely if it's not broke don't fix it.
the code is here if you want to look.
https://github.com/Dronecode/SiK/blob/master/Firmware/radio/mavlink.c
It would take code for both radios, update to mission planner for both the radio configuration, and decode the new MAVlink message.
The other way, would require the same amount of trouble, create a new MAVlink message for the APM or Pix to send out, Mission planner update to config the APM. doing it this way the code for the APM is changing all the time and we might get the developers to do it, as the radio firmware hasn't been updated in years.
I have a set of 1 watt radios that I wanted to find a way to send call-sign for just airborne radio.
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