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Jun 08, 2021, 12:44 PM
MrMPX's Avatar
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Discussion

At what point of firmware / software does the FCC type cert get voided?


Just opening this topic back up.
There are loads of hacks / modifications and open TX systems out.

Valid question is when are modifications so extensive they void the FCC type certification?

Was a Long and hard battle with the FCC just to get to be able to allow crystal changes by end users in a TX!

Now whole RF deck swaps, OPEN TX platforms that may or may not be able to modify the TX beyond the FCC type cert.
AMA contests and insurance on modified transmitters and receivers?

Just a discussion.
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Jun 14, 2021, 09:58 PM
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opjose's Avatar
Since SDoc does not apply to transmitters, only receivers, as I understand it the certification deals with a transmitting system as a whole.

With SDoc the manufacturer can simply declare conformity for additional components.

So by that read each swappable module will require certification of compliance when used with the mother device.

Software clouds the issue if the software is capable of changing frequencies, protocols and power output. I assume most open platforms do not due to the additional associated costs.

Here is the document that addresses modular transmitter systems....

https://apps.fcc.gov/eas/comments/Ge...d=50&tn=916170
Jun 14, 2021, 11:27 PM
MrMPX's Avatar
Thread OP
Exactly. It should also be mentioned that 2.4GHz receivers are also most time transmitting as well. Even confusing the matter further.

But does Opent TX allow re setting of RF output, do not think it does?
We had the issue when I was working with Nomadio we have to have a software "switch" for FCC cert countries and CE cert countries. CE was a higher RF output but same protocol. So if that switch was triggered in the USA the radio would technically not be FCC type certified while in that mode. Did people do it? Yes but we never advertised there was a power difference
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Jun 14, 2021, 11:57 PM
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opjose's Avatar
Quote:
Originally Posted by MrMPX
But does Opent TX allow re setting of RF output, do not think it does?
I guess that is the big question.

Given the additional control circuitry required and the cost of incorporating it, I assume the TX manufactures would not bother.

By fixing limiting the power output to the maximum they claim certification for they eliminate a lot of certification costs and potential lawsuits later.

Of course they can "reduce" the output in software if they wish and still be compliant (range test).
Jun 15, 2021, 04:21 AM
MrMPX's Avatar
Thread OP
Not only the power that is tested to get part 15 cert. So it's an interesting issue.
There is a guy selling a Multiplex Royal Evo on eBay with an rf deck I know was never certified with the radio. He told me I was full of it. Was really funny as I was behind the original cert and know ProgiRoyalNT9 was a 72MHz cert. Hitec did a letter to file taking over the cert as they became the importer of record or that cert would still have my name on it. Lol
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Jun 15, 2021, 07:16 AM
AndyKunz's Avatar
Quote:
Originally Posted by MrMPX
CE was a higher RF output but same protocol.
Most companies do it the other way - they take advantage of the 200mW allowed in the USA, and limit to the 100mW max permitted in the EU.

Andy
Jun 15, 2021, 08:57 AM
MrMPX's Avatar
Thread OP
Quote:
Originally Posted by AndyKunz
Most companies do it the other way - they take advantage of the 200mW allowed in the USA, and limit to the 100mW max permitted in the EU.

Andy
Yes you are correct I was backwards after a long day..
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Jun 15, 2021, 09:54 AM
Sagitta Fanboy
Quote:
Originally Posted by MrMPX
Exactly. It should also be mentioned that 2.4GHz receivers are also most time transmitting as well. Even confusing the matter further.

But does Opent TX allow re setting of RF output, do not think it does?
We had the issue when I was working with Nomadio we have to have a software "switch" for FCC cert countries and CE cert countries. CE was a higher RF output but same protocol. So if that switch was triggered in the USA the radio would technically not be FCC type certified while in that mode. Did people do it? Yes but we never advertised there was a power difference
OpenTX is just a radio OS.

It only allows the settings that the RF module in question lets it set.

It's the RF module that needs to have legal firmware or setting loaded.

For example, the older FrSky iXJT modules switched between CE and FCC legal versions by loading region-specific firmware. The newer ISRM ones have a configuration variable set on the module to control CE/FCC versions.
Jun 17, 2021, 12:28 AM
Registered User
opjose's Avatar
Quote:
Originally Posted by mawz
OpenTX is just a radio OS.

For example, the older FrSky iXJT modules switched between CE and FCC legal versions by loading region-specific firmware. The newer ISRM ones have a configuration variable set on the module to control CE/FCC versions.
Right, but under the FCC certification requirements the module would have to be tested at the higher power settings even if the U.S. only permitted operating under the lower settings.

This has come up in with consumer radio transmitter consoles.
Jun 17, 2021, 08:03 AM
Sagitta Fanboy
Quote:
Originally Posted by opjose
Right, but under the FCC certification requirements the module would have to be tested at the higher power settings even if the U.S. only permitted operating under the lower settings.

This has come up in with consumer radio transmitter consoles.
Yes, but that's got nothing to do with OpenTX, only the module firmware. OpenTX is just the UI and input mixer for the RF system.

It's also irrelevant in this case, as the FCC-legal power settings are the highest available in this case. It's EU/CE that would need to potentially test at higher power settings that are not compliant (and that would be limited by CE certification requirements)
Jun 17, 2021, 01:28 PM
Registered User
opjose's Avatar
Technically correct.

But we typically use "OpenTX" to signify the class of radios that utilize that firmware as a shortcut while not specifying manufacturers of the devices.

Since we were talking about FCC certification, the example I gave about power output is an anecdotal.

It is a relevant example of an issue that can arise with software controlled power output setting in a transmitting device. It has come up before.
Jun 17, 2021, 03:29 PM
Registered User
You might want to ask the same question about the multi module based transmitters and see how excited people get
Jun 17, 2021, 04:29 PM
Registered User
opjose's Avatar
The involvement levels are quite palpable!
Jun 18, 2021, 12:14 PM
Registered User
Exactly - that community does not give a rip.


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