gaznav wrote:@rjc101
Thanks again for your thoughts, opinion and fact. I’ve thought a lot about what you have written today. But I couldn’t help thinking that when it comes to stray “wigglies” what about the many USB chargers that are used with the very many different USB cables (of different lengths) connected to the many different mobile phones and tablets used in GA aircraft? Many of these phones and tablets are transmitting on the 4G 800 MHz band and the chargers may be the ones that your own company produce to a suitable test schedule. But from what you’re saying I take it that you can’t use any USB cable connected to one of these certified chargers unless it’s been through the same testing regime for EMC? Also, how could every possible combination have been tested too in order to ensure carry-on device don’t cause the interference you state?
In my post, I said product X, specifically not to mention chargers. The X could be a softRF transmitting device using a different type of badly suited coax cable to a mismatched antenna. I was trying to keep everything generic. I have also suppressed my normal signature on this type of post too, as it links to my charger website. It didn’t seem appropriate for this subject. You have created a link where there isn't one.
As you have brought the charger subject up...
In your example, both the USB charger and the phone will have passed regulatory testing. The aim of this, and the reason why there are such tests, is to prevent the scenario you created. You are free to use any cable, that meets the USB specification, and all should be well *.
The problem is many USB chargers from online stores have never been tested and some are frankly dangerous, regardless of what the adverts say. Hence you can have issues where item X works fine for me but is terrible for you.
* However, note that the EMC limits for consumer devices are much higher at some frequencies than those for aviation, especially around the VHF radio comm / NAV and GNSS frequencies, hence why many people have issues with generic plug-in chargers in aircraft. People use them because they are deemed affordable and they have an old cigarette lighter socket to plug them into, even though they are not ideally suited for use in the GA environment. {edit to add numbers} For standard consumer CISPR between 108MHz to 152MHz the limit is 65dBuV/m, for Class M aviation it is 35dBuV/m to 37dBuV/m. For Class H (potentially more appropriate to GA as it is for emissions nearer to antenna, but the standards are geared toward CAT) it is 25dBuV/m to 27dBuV/m.
gaznav wrote:Also, you don’t seem to take issue with these ‘development boards’ being used on the ground? But that doesn’t really make sense from my perspective, as the radio waves care not if they are being emitted from the ground or the air if this is something that affects many aircraft at range. If you are worried about emissions interfering with the electronics and nav aids within or in the close vicinity of aircraft - then many have none in aircraft that they fly (I can’t imagine any effect it could have on a 1952 Chipmunk and a 1967 Condor that I fly)? If these development boards are such an issue then surely they would be outlawed, but they aren’t, and there are literally hundreds of thousands of them out there in use for the various things I have already stated.
I have an issue with any development board, or untested system, being used on the ground or in the Air in a device being sold. It is more concerning when the devices actively transmit. When people DIY solutions they are not products, so legally require no testing. However, the operator is still legally responsible for anything the device may do outside the legal limits. So you are free to do as you wish, providing you accept it’s your responsibility, even if you have no idea there even is an issue.
In your aircraft scenario, it may well not affect you. However, if you are transmitting FLARM at too much power, or the transmitter design is poor so it has way too much power at the start (TX power overshoot), or it takes too long to stop transmitting, that signal could cause issues for other nearby FLARM installations. We shall ignore the potential situation when FLARM issue an update that tweaks the protocol, and the official installations are updated but the OpenSource project lags behind or the DIY'ers never update them. Now you may be actively causing problems for others, because you may not have checked the module was updated and applied it.
gaznav wrote:As you appear to be in the AV/IT consultancy game then the ubiquity of these boards should be well known to you, too, as they are used for various IOT purposes. I also understand that the Open Glider Network is using these boards too in various devices of their own design. So I suspect they are everywhere now, and being used in various GA types across Europe in various devices - and in the air and on the ground. SoftRF and Stratux EU with these development boards are being used by more than just a few folks - indeed SoftRF was used to track the FAI Grand Prix World Final in 2019.
If this is the significant problem that you suggest, wouldn’t it be the right thing to do to raise the dangers that these devices supposedly pose to GA to Ofcom or the CAA or EASA?
I am indeed an independent IT/AV consultant, but I also do custom electronics design and embedded firmware. Mostly bespoke for specific requirements. I have some of my work on the website, some I cannot post details nor discuss owing to NDA's or other legislation.
I am aware of lots of these type of boards. Generally, it is those used to transmit where issues have come up. As the whole design is more critical to correct performance. More often it is a problem with the supporting electronics than the RF modules themselves. A poorly executed design, often combined with sub-optimal component choices to keep the cost down. I suspect most of the deployment scenarios you describe are used as receivers rather than transceivers. For me, it is the transmitting side where you can create problems for others. If you do something that only causes you grief, it's not good but I don't mind that so much (nothing personal). When there is the potential to impact others, it is a concern.
I recall a discussion where a different, but similar, board being DIY’d as a drive gate opener and gate bell/intercom extender. It worked fine, only when they used the intercom it caused jamming errors on the wireless alarm system. This was “resolved” by buying a different style of the board from AliExpress. It may still cause problems elsewhere, but as the alarm fault went away the owner didn’t worry about it. They were not concerned that it might impact anyone else, it was cheap and that trumped everything else.
When lots of people do the same because it’s "Cheap and Cheerful", you can end up with lots of small problems waiting to catch someone out. There is no source to register a complaint against, the boards are not sold with testing done for any particular purpose. For me, the consequence of something bad happening could be worse in the air than on the ground. Especially if it causes something to happen that increases the workload of the pilot. I have previously made comments via CHIRP in response to reported events.
gaznav wrote:I know that you manufacture USB chargers for GA aircraft, but have you declared any commercial interest in EC devices that you have as I see that your website advertises the Pilot Aware? I’m sorry if that comment is ‘below the belt’ but there is so much commercial interest at stake here, I’m finding it hard to work out who to trust and what their motives are. Other EC manufacturers have been keen to raise the fact that Stratus EU and SoftRF emit and receive their protocol, so I hope you understand how conflicted that message is to those that are just trying to understand the best and most cost-effective options?
I have no link or commercial arrangement with PilotAware, nor any EC device. As one use for my chargers is to power the devices I have a page on the site for that from the early days of PilotAware. The PAW team tested and mention my chargers the same as they do for the Anker range of plug-in chargers. The page does also help with SEO. I added it years ago, and do need to update or edit that page to be more generic, cover different EC devices or remove it.
I have a policy that I neither solicit nor accept referral fees or kickbacks. This is stated on the front page of my main website. I have walked away from projects where I was offered referral fees to steer things in a specific direction. It’s not how I believe things should be done. Hence why I have specifically kept what my company does out of the conversation until you raised the subject.
{edited to put replies and comments in context, fix typos etc.}