Liability of Open Source radios

[Former Member]

[This posting has been removed]

[Denis Watkins]

There is only one driver, with only one registration number; that is the Pilot Barrie.

Sorry, my Wi-Fi went weak. 

No matter what gear is used, the Pilot decides it is ok to make the flight.

Edited By Denis Watkins on 06/04/2020 11:16:27

[Former Member]

[This posting has been removed]

[Mike T]

To backtrack from what Denis says, once you have satisfied that your radio is OK to make the flight, any operator error in the use of the programming is as much a 'dumb thumb' as pulling 'up' when inverted. So it's a honest mistake which insurance would cover.

Re use of mix 'n match modules, same applies - as long as you satisfy yourself it's ok, then you're covered. As it's the transmission frequency and power that is covered by the various regulations, then as long as your module carries a CE mark confirming compliance, then you're covered. It is not for you to worry about whether that mark is genuine or not (unless you import it directly, which opens up a whole new can of peas...)

[Former Member]

[This posting has been removed]

[Mike T]

Posted by Barrie Lever on 06/04/2020 13:02:20:

To be clear I was meaning a software programming error in the open source software that under some undetermined set of parameters caused a loss of control, so which of the open source contributors was responsible?

Barrie, in the circumstances you describe above, IMO the pilot would be responsible, but I don't think, in the legal sense, that they would be held to be 'negligent'.

I'm way beyond my knowledge here, so I hope one of the OS gurus steps in to help, but if, for example, you were to make your own changes to the OS code without them being reviewed/cleared by the OS community, then that might be construed as 'negligent'.

[flight1]

There has been software/ hardware failure causing crashes in the past with well established makes. But has that led to anything? it be very hard to prove and proberly cost prohibitive.

i reccon that open source is the the basis of a few manufacturs operating system and then there is the transmission chips and coding? could be at blame too and these chips are used across different manufactures like Texas Instruments CC2500 RF Chip used by JR DMSS, HiTec, Corona, FrSky, Tactic, Futaba S-FHSS, Skyartec, futaba and FrSky use the same chip

All very muddy waters so its down to the operator/pilot to verify that it is all safe to fly.

as for the CE mark thats just to confirm the rf side of things confirm to UE regulations not any of the software

Edited By flight1 on 06/04/2020 13:35:09

Edited By flight1 on 06/04/2020 13:36:00

[Nigel R]

Posted by Barrie Lever on 06/04/2020 13:02:20:

the assumption is that that company has done full testing

There is testing... and then there is testing.

Mike

Perhaps that depends on whether you are competent, by some defintion. Such as one of the regular development team adding features, perhaps. Or maybe you have extensive prior software authoring experience.

I'm not sure the common open source licenses cover liability, beyond state "no liability is assumed by the author" or something like that - onus be on the operator.

[Former Member]

[This posting has been removed]

[Gary Manuel]

Extract from page 1 of the OpenTX manual - in highlighted print reads:

"It is the sole responsibility of the user to ensure that the setting up of their transmitter functions as expected on the model."

[Mike T]

Thanks Nigel/Gary.

Looks like use of an OS system falls into the legal category of "Son, you're on your own..."

[Peter Christy]

I'm not sure what the difference is between Open Source and proprietary code in this case. I can't think of a single instance being reported where Futaba, Jr or any other manufacturer has been held responsible for an accident involving RC gear.

Hardware failure is a far more likely scenario than software failure, and in the past its proven almost impossible to claim for incurred losses even when a demonstrable hardware failure has occurred. When such cases have occurred, the manufacturer has offered to repair the radio gear (usually FOC), but the loss of the model or any other damages is down to the owner and his/her insurance where appropriate.

One of the beauties of open source is that far many more eyes are examining the code than is the case with proprietary software, and when faults are found, they are usually fixed much more rapidly.

--

Pete

[Martin Harris - Moderator]

I can't claim any legal expertise but the guiding principle seems to be what a reasonable person could be expected to do. While flying with a known problem could be held to be negligent, an unintended consequence of mixing and matching or home built/programmed equipment which has been tested reasonably before flight shouldn't lead to any accusations of negligence or culpability as far as I can see.

[Former Member]

[This posting has been removed]

[Mike Blandford]

The open source software is released under the GNU General Public License.

V2: **LINK**

V3: **LINK**

Extract from the V2 version, the V3 version is similar:

NO WARRANTY

11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, REPAIR OR CORRECTION.

12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.

Mike

[Phil Green]

Posted by flight1 on 06/04/2020 13:34:04:

.. these chips are used across different manufactures like Texas Instruments CC2500 RF Chip used by JR DMSS, HiTec, Corona, FrSky, Tactic, Futaba S-FHSS, Skyartec, futaba and FrSky use the same chip

Sorry thats not true. JR DMSS is ZigBee 802.15.4 its not the cc2500

[Andy Stephenson]

I heard of a case where it is possible to adjust the TX output power on open source radios by reprogramming the RF chip. If the power is increased by tinkering with the code and this consequently causes interference to other users who then is liable. More to the point how would you ever prove it.

A.

[flight1]

Posted by Phil Green on 06/04/2020 16:34:55:

Posted by flight1 on 06/04/2020 13:34:04:

.. these chips are used across different manufactures like Texas Instruments CC2500 RF Chip used by JR DMSS, HiTec, Corona, FrSky, Tactic, Futaba S-FHSS, Skyartec, futaba and FrSky use the same chip

Sorry thats not true. JR DMSS is ZigBee 802.15.4 its not the cc2500

the most widely deployed enhancement to the 802.15.4 standard is ZigBee standard , which is a standard of the ZigBee Alliance. The organization maintains, supports, and develops more sophisticated protocols for advanced applications. So Zigbee 802.15.4 is not a RF chip it is something it uses... so what chip does it use then?

[Andy48]

Posted by Andy Stephenson on 06/04/2020 17:41:04:

I heard of a case where it is possible to adjust the TX output power on open source radios by reprogramming the RF chip. If the power is increased by tinkering with the code and this consequently causes interference to other users who then is liable. More to the point how would you ever prove it.

A.

Since the programming for the RF chip is not open source but manufacturer's software, then I cannot see any worse problem than with any other make of transmitter.

[Mike Blandford]

The multi-protocol module firmware is open source (started as a hardware and software DIY project), and this controls the RF chip(s) directly. They all have an output power setting controlled by the firmware.

Mike

[Phil Green]

Posted by flight1 on 06/04/2020 21:04:02:

Posted by Phil Green on 06/04/2020 16:34:55:

Posted by flight1 on 06/04/2020 13:34:04:

.. these chips are used across different manufactures like Texas Instruments CC2500 RF Chip used by JR DMSS, HiTec, Corona, FrSky, Tactic, Futaba S-FHSS, Skyartec, futaba and FrSky use the same chip

Sorry thats not true. JR DMSS is ZigBee 802.15.4 its not the cc2500

the most widely deployed enhancement to the 802.15.4 standard is ZigBee standard , which is a standard of the ZigBee Alliance. The organization maintains, supports, and develops more sophisticated protocols for advanced applications. So Zigbee 802.15.4 is not a RF chip it is something it uses... so what chip does it use then?

CC2520. (a completely different animal animal, even though numerically it sounds similar.

[Andy Stephenson]

Posted by Andy48 on 06/04/2020 21:29:37:

Posted by Andy Stephenson on 06/04/2020 17:41:04:

I heard of a case where it is possible to adjust the TX output power on open source radios by reprogramming the RF chip. If the power is increased by tinkering with the code and this consequently causes interference to other users who then is liable. More to the point how would you ever prove it.

A.

Since the programming for the RF chip is not open source but manufacturer's software, then I cannot see any worse problem than with any other make of transmitter.

Andy48

I will try to find the original document that explains how this was done. Not necessarily through the normal open source route but still possible with a little research.

A.

[Andy Stephenson]

Andy48

The document I referred to above appears as a email circulated by Duncan McClure South Midalnds Area Delegate to the BMFA and recommends that a local club adopts an embargo of open source radios as he maintains it IS possible to change the power settings using this system.

I have now seen this email but it is an internal club communication so I won't put it online without permission.

You may want to contact Duncan directly on this subject.

Andy.

[Peter Christy]

Whilst it may (in theory) be possible to increase the power output of any system (even 35 MHz!), the extra output available at 2.4 GHz is trivial.

Going from 100 to 200 mW may sound a lot, but a more accurate way of perceiving it is by the dBm figure. 100mW=20dBm, 200mW=23dBm. The dBm figure is a far more realistic way of imagining the increase.

You will get a similar increase just by replacing the standard antenna (2dB gain) with a "high gain" one (typically 5dB gain - a similar 3dB increase!), without ever having to adjust the Tx at all. And that applies to ANY transmitter, Open Source or not.

All the transmitters I have looked at have a typical output of 60mW. The 2dB gain of the antenna raises this to 100mW erp (Effective Radiated Power). It does this by concentrating the RF output in a specific direction, a bit like a torch bulb being "brightened" by placing a reflector behind it - but only in a specific direction.

The higher the gain of the antenna, the more directional it becomes, so higher gains do not necessarily improve performance in our application.

Note: What I am talking about here is "squishing" the doughnut shaped radiation pattern of a typical RC antenna, ie: making the "dead spot" off the tip deeper and wider.

In practice, yes, increasing the output of the transmitter by either a firmware tweak (not trivial!) or using a higher gain antenna (simple!) does break the regulations.

The likely impact of a 3dB increase in power on other users in a typical model club environment approximates to - er - zero! The likely advantage of such an increase to the user approximates to - er - zero! In the case of high gain antennas, the narrower beam of the signal may well prove detrimental!

Note that I am NOT recommending modifying the RF output of our transmitters. 100mW / 20dBm is more than adequate for our purposes, and increasing it does not do our reputation with the powers-that-be any good, at a time when we need all the friends that we can get!

The only system I know of that actually offers 200 mW is (or was?) Spektrum - which is NOT open source! The US versions do - or certainly did at one time - use 200mW, as permitted by FCC regulations. EU versions are restricted to 100mW, but of course if someone grey imports a US spec set........

--

Pete

[Gary Manuel]

If anyone wanted to increase the power output, they could do it to ANY transmitter by adding a signal amplifier and patch antenna. I'm betting that there are commercially available WiFi signal amplifiers that would do the job.

Is the club that is banning open source radios going to ban ALL transmitters because it's possible to increase the power output of these too?

Edit - Peter posted while I was typing.

Edited By Gary Manuel on 08/04/2020 11:58:21