Transmitting in VFO/Frequency Mode - Possible?

[htims05]

Is it possible to transmit in frequency mode on the GM-30 or UV-5X radio...and I mean transmitting in GMRS frequencies?  On mine they just beep and no red LED like other radio's (or when in channel mode).  I wonder if I have something set wrong as the manual's seem to indicate it's possible.

[mbrun]

In order to keep the Part 95 certification, VFO transmit has to be disabled for anything other than the GMRS frequencies, my guess is its easier to disable VFO transmit all together, which appears what they did.

All the Wouxun GMRS radios with a VFO mode can all transmit on all GMRS frequencies while in VFO mode.


Michael
WRHS965
KE8PLM

[MichaelLAX]

22 minutes ago, Radioguy7268 said:

Pretty sure that enabling VFO mode disables the FCC Part 95 cert. Unless they got one of the overseas labs to "certify" it with that feature enabled. Wouldn't be the first wonky Type Cert that I've seen.

Same as enabling Wideband with a firmware patch on a radio that only got Type Accepted/Certified for Narrowband. 

What a can of worms, eh? 

Why would a VFO mode that allows for transmission only on a GMRS frequency disable Part 95 certification?  Just wondering...

[dirkvan]

On 10/1/2021 at 12:54 PM, MichaelLAX said:

The TYT TH-UV 88 Ham Radio clone of the Radioddity GM-30, has keyboard codes that will open up the VFO to transmit and additionally both VFO and Channel mode can transmit on GMRS and MURS.

Do they work on the GM-30? Where can they be found? Asking for a friend....

[tweiss3]

In order to keep the Part 95 certification, VFO transmit has to be disabled for anything other than the GMRS frequencies, my guess is its easier to disable VFO transmit all together, which appears what they did.

[MichaelLAX]

The TYT TH-UV 88 Ham Radio clone of the Radioddity GM-30, has keyboard codes that will open up the VFO to transmit and additionally both VFO and Channel mode can transmit on GMRS and MURS.

[Radioguy7268]

Pretty sure that enabling VFO mode disables the FCC Part 95 cert. Unless they got one of the overseas labs to "certify" it with that feature enabled. Wouldn't be the first wonky Type Cert that I've seen.

Same as enabling Wideband with a firmware patch on a radio that only got Type Accepted/Certified for Narrowband. 

What a can of worms, eh? 

[Lscott]

Per the FCC rules they state the following:

https://www.ecfr.gov/current/title-47/chapter-I/subchapter-D/part-95

"§ 95.1761 GMRS transmitter certification.

..... No GMRS transmitter will be certified for use in the GMRS if it is equipped with the capabilities to operate in services that do not require equipment certification, such as the Amateur Radio Service. All frequency determining circuitry (including crystals) and programming controls in each GMRS transmitter must be internal to the transmitter and must not be accessible from the exterior of the transmitter operating panel or from the exterior of the transmitter enclosure. "

Yes there are radios that "allow" FPP, front panel programming, but with conditions. Many require a deliberate hardware modification, typical diode, resistor or solder shunt removable, and enabling in the radio's programming software. Others require entering a "secret code" to switch operating modes, typical of the Chinese radios.

So, as long as the radio is configured to comply with 95.1761 it is operating under GMRS rules it's legal. The moment this is violated you're not compliant so the transmitter is now operating with illegal functionality and loses it's certification, even if it isn't being used. Of course it can be switched back, in which case the radio again would be in compliance, and the certification once again applies if it had it to begin with.

My Kenwood commercial radios can be modified for FPP, needs the hardware mod and the feature enabled in the software. There is a warning that radios MUST NOT be returned to the end user(s) with FPP feature enabled, so it's disabled in the software with the modified code plug written to the radio. Of course if the radio is ONLY going to be used on the Ham bands it's not a problem.

The problem revolves around the last sentence quoted above. Some feel just because the feature is there then there is no issue with enabling it. The FCC is clear that's not the case. There is no mention that one must be using the feature, the mere fact it's "possible" to access through some action(s) performed by the user is enough to void the certification. This includes changing the "mode" though any means accessible by the user external to the radio, such as pressing a sequence of buttons etc. during power up or any other time.

There is a VERY fine line with switching modes through a sequence of button presses. There is a reason why it's NOT documented, at least for anything an end user gets to read. The user isn't supposed to even know about it. This could be considered a violation of the above section of the FCC rules. If there is any debate it would be over this point alone. Everything else is fairly clear cut IMHO.

[mbrun]

Pretty sure that enabling VFO mode disables the FCC Part 95 cert. Unless they got one of the overseas labs to "certify" it with that feature enabled. Wouldn't be the first wonky Type Cert that I've seen.
Same as enabling Wideband with a firmware patch on a radio that only got Type Accepted/Certified for Narrowband. 
What a can of worms, eh? 

Good day Radioguy. Good to see you back in the chat again.

I think many interpret that, but that has never been my interpretation. What Wouxun seems to have done on some radios is bake the FCC rules into the radio’s firmware so that only valid combinations of frequencies and power can Tx, regardless of whether the radio is in VFO or Channel mode. And honestly, if a manufacturer is truly targeting 95e compliance, that is exactly what I would expect out of them. On some models not even a novice operator can mess it up.


Michael
WRHS965
KE8PLM

[mbrun]

Per the FCC rules they state the following:
https://www.ecfr.gov/current/title-47/chapter-I/subchapter-D/part-95
"§ 95.1761 GMRS transmitter certification.
..... No GMRS transmitter will be certified for use in the GMRS if it is equipped with the capabilities to operate in services that do not require equipment certification, such as the Amateur Radio Service. All frequency determining circuitry (including crystals) and programming controls in each GMRS transmitter must be internal to the transmitter and must not be accessible from the exterior of the transmitter operating panel or from the exterior of the transmitter enclosure. "
Yes there are radios that "allow" FPP, front panel programming, but with conditions. Many require a deliberate hardware modification, typical diode, resistor or solder shunt removable, and enabling in the radio's programming software. Others require entering a "secret code" to switch operating modes, typical of the Chinese radios.
So, as long as the radio is configured to comply with 95.1761 it is operating under GMRS rules it's legal. The moment this is violated you're not compliant so the transmitter is now operating with illegal functionality and loses it's certification, even if it isn't being used. Of course it can be switched back, in which case the radio again would be in compliance, and the certification once again applies if it had it to begin with.
My Kenwood commercial radios can be modified for FPP, needs the hardware mod and the feature enabled in the software. There is a warning that radios MUST NOT be returned to the end user(s) with FPP feature enabled, so it's disabled in the software with the modified code plug written to the radio. Of course if the radio is ONLY going to be used on the Ham bands it's not a problem.
The problem revolves around the last sentence quoted above. Some feel just because the feature is there then there is no issue with enabling it. The FCC is clear that's not the case. There is no mention that one must be using the feature, the mere fact it's "possible" to access through some action(s) performed by the user is enough to void the certification. This includes changing the "mode" though any means accessible by the user external to the radio, such as pressing a sequence of buttons etc. during power up or any other time.
There is a VERY fine line with switching modes through a sequence of button presses. There is a reason why it's NOT documented, at least for anything an end user gets to read. The user isn't supposed to even know about it. This could be considered a violation of the above section of the FCC rules. If there is any debate it would be over this point alone. Everything else is fairly clear cut IMHO.

The key is the word ‘operate’. In radio lingo ‘operate’ is synonymous with transmitting. For part 95e certification I interpret that that the FCC does not want user’s having the indiscriminate ability to transmit in other services, and they do prescribe what is allowed in GMRS. If the radio firmware enforces the rules, regardless of mode, I think the intent of the FCC requirements are fully satisfied.


Michael
WRHS965
KE8PLM

[Lscott]

2 hours ago, mbrun said:

The key is the word ‘operate’. In radio lingo ‘operate’ is synonymous with transmitting. For part 95e certification I interpret that that the FCC does not want user’s having the indiscriminate ability to transmit in other services, and they do prescribe what is allowed in GMRS. If the radio firmware enforces the rules, regardless of mode, I think the intent of the FCC requirements are fully satisfied.


Michael
WRHS965
KE8PLM

The rules are written the way they are because the underlying assumption is the user is a non technical person who has no idea what the difference is between Hertz and Hurts. The rules are designed to prevent interference to other services regardless of how a user manipulates the radio’s controls, either deliberately or by accident. 

Hams are held to a higher technical standard, and assumed to know where the bands are located frequency wise. There are few out there that would be challenged using two soup cans connected by a string, it’s not a guarantee somebody is competent just because they have a Ham license. It’s not a perfect world.

[mbrun]

The rules are written the way they are because the underlying assumption is the user is a non technical person who has no idea what the difference is between Hertz and Hurts. The rules are designed to prevent interference to other services regardless of how a user manipulates the radio’s controls, either deliberately or by accident. 
Hams are held to a higher technical standard, and assumed to know where the bands are located frequency wise. There are few out there that would be challenged using two soup cans connected by a string, it’s not a guarantee somebody is competent just because they have a Ham license. It’s not a perfect world.

I agree with you on all counts.


Michael
WRHS965
KE8PLM

[WSBW539]

On 10/1/2021 at 1:32 PM, mbrun said:

All the Wouxun GMRS radios with a VFO mode can all transmit on all GMRS frequencies while in VFO mode.


Michael
WRHS965
KE8PLM

How

[mbrun]

How

Enter VFO mode on the radio. The manual explains how. Select a frequency that is valid for GMRS use. Press PTT.

The Wouxun Part 95 radios sold by BTWR with VFO modes have special firmware that has the FCC limits baked into it. The firmware knows the GMRS frequencies, the power limits, the offset and bandwidth limits. So whether you are in VFO mode or Channel Mode, the radio will only transmit in accordance with Part 95 rules.

This is confirmed true on the KG-1000G & Plus, KG-935G & Plus,
KG-S88G, KG-Q10G. The 805G and 905G do not have official VFO modes so switching to and Tx’ing in VFO mode is not applicable. If memory serves, even the 20-watt mobile can do this, at least the first generation could.


Michael
WRHS965
KE8PLM

[MichaelLAX]

14 minutes ago, dirkvan said:

Do they work on the GM-30? Where can they be found? Asking for a friend....

No, and I am not aware of any hack for the GM-30 or its clone, the Pofung P15UV to open them up