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Using 462.xxxx MHz Frequencies Outside of GMRS Channels


WSEI687

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I have searched long and hard and have not found an answer to this question:

Probably more common than not, my radios have the ability to create Tx/Rx channels with any frequency that I choose. I created a "private" channel using the frequency 462.5375 MHz, which is just below the GMRS channel 1 (462.5625). Is this violating any FCC rules and / or potentially creating any problems? Yes, I do have an active GMRS license.

Thanks in advance for any feedback!

WSEI687 Dale

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On 10/13/2024 at 7:55 PM, WSEI687 said:

Is this violating any FCC rules

Absolutely.

On 10/13/2024 at 7:55 PM, WSEI687 said:

potentially creating any problems?

Yes. There are other people using frequencies outside of the ones officially allocated for GMRS. That's why the FCC exists. It's their job to make sure various groups of users don't interfere with each other.

This should give you an idea just how packed the radio spectrum is. The FCC has to keep track of this mess.

https://www.ntia.doc.gov/files/ntia/publications/2003-allochrt.pdf 

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Yes it is very wrong. Many of those frequencies are public safety or other use.   If you actually read the gmrs license agreement before you paid your fees you would know that 1st you may only use a gmrs radio that only has the 22 gmrs channels and 8 repeater pairs. If you’re using a radio that tx’s on any other frequencies you are already in violation.   2nd you would know that gmrs user may only use those “channels”.   Obviously you are not one of those people that reads the rules before agreeing to them.   

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2 minutes ago, WRKW566 said:

You have done a no no.

The GMRs channels are non-negotiable. You use only the listed frequencies.

Tempting as it is to use your radio's flexibility, GMRS is not a free-range of bandwidth.

Yup.  But a “gmrs” radio does not have any flexibility to use.  A gmrs radio is locked down.    

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As others have said, one of the reasons that only type-accepted radios are supposed to be used on GMRS is that those radios can only transmit on the GMRS frequencies.

Obviously the radio you are using is not FCC Part 95E accepted.  It's up to you whether or not that is important.

But the "private frequency" you picked is a Part 90 business frequency.  You are not allowed to transmit on that frequency.

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On 10/13/2024 at 4:55 PM, WSEI687 said:

I have searched long and hard and have not found an answer to this question:

Probably more common than not, my radios have the ability to create Tx/Rx channels with any frequency that I choose. I created a "private" channel using the frequency 462.5375 MHz, which is just below the GMRS channel 1 (462.5625). Is this violating any FCC rules and / or potentially creating any problems? Yes, I do have an active GMRS license.

Thanks in advance for any feedback!

WSEI687 Dale

And also below GMRS channel 15 (462.550 Megs).

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On 10/13/2024 at 4:55 PM, WSEI687 said:

I have searched long and hard and have not found an answer to this question:

Probably more common than not, my radios have the ability to create Tx/Rx channels with any frequency that I choose. I created a "private" channel using the frequency 462.5375 MHz, which is just below the GMRS channel 1 (462.5625). Is this violating any FCC rules and / or potentially creating any problems? Yes, I do have an active GMRS license.

Thanks in advance for any feedback!

WSEI687 Dale

In order to not piss-off the FCC you would need a Radio Station Authorization licensed to transmit that Part 90 freq with a BANDwidth not to exceed 4 KHz.

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On 10/13/2024 at 5:55 PM, WSEI687 said:

I have searched long and hard and have not found an answer to this question:

Probably more common than not, my radios have the ability to create Tx/Rx channels with any frequency that I choose. I created a "private" channel using the frequency 462.5375 MHz, which is just below the GMRS channel 1 (462.5625). Is this violating any FCC rules and / or potentially creating any problems? Yes, I do have an active GMRS license.

Thanks in advance for any feedback!

WSEI687 Dale

Dale,

As others have commented you are transmitting on a frequency that isn’t a GMRS channel with a non-GMRS certified transmitter.  Your license only grants you permission to transmit on the official GMRS channels and only when using GMRS certified transmitter.  So, technically you’re violating the regulations and by publishing your question in a public forum you have increased your risk of being fined.  The good news is that the FCC typically doesn’t do anything unless someone files a complaint and even then they send you a stern letter first demanding that you cease and desist and confirm in writing to them how you intend to avoid doing such a terrible thing ever again.

Just delete that channel and use the established channels at the permitted power levels and go in peace. ✌️😁

 

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7 minutes ago, Socalgmrs said:

Yup.  But a “gmrs” radio does not have any flexibility to use.  A gmrs radio is locked down.    

That is true!

But as much as we all hate to admit, the OP has a radio that is not a GMRS radio.

They will still use it and if they cared enough to come here and ask, then they probably care enough to conform their use of whatever radio they have to GMRS rules.

Anyone with enough sense in their head to program a radio to operate out-of-band knows they have a non-approved radio. No one is going to go there and take it away from them. I would prefer to encourage them to use that radio to cause as little trouble as possible.

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14 minutes ago, wrci350 said:

Obviously the radio you are using is not FCC Part 95E accepted.  It's up to you whether or not that is important.

 

More than that.  Even if it was Part95E labeled for GMRS operation.  Getting it to operate outside of the GMRS allocation would require a modification to the radio (software or hardware mod) which immediately invalidates the type acceptance of the radio, or ANY RADIO that you are modifying to operate out of the design parameters of the radio when it was new. 

To the OP

What you have done is no different than putting 'extra channels' in a CB radio above CH40 and below CH1.  You can't operate there either. 

And understand that getting caught doing that is gonna get your GMRS license revoked. 

 

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4 hours ago, SteveShannon said:

Dale,

As others have commented you are transmitting on a frequency that isn’t a GMRS channel with a non-GMRS certified transmitter.  Your license only grants you permission to transmit on the official GMRS channels and only when using GMRS certified transmitter.  So, technically you’re violating the regulations and by publishing your question in a public forum you have increased your risk of being fined.  The good news is that the FCC typically doesn’t do anything unless someone files a complaint and even then they send you a stern letter first demanding that you cease and desist and confirm in writing to them how you intend to avoid doing such a terrible thing ever again.

Just delete that channel and use the established channels at the permitted power levels and go in peace. ✌️😁

 

And keep some of your newfound friends from dropping some dimes on you.

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On 10/13/2024 at 5:55 PM, WSEI687 said:

I have searched long and hard and have not found an answer to this question:

Probably more common than not, my radios have the ability to create Tx/Rx channels with any frequency that I choose. I created a "private" channel using the frequency 462.5375 MHz, which is just below the GMRS channel 1 (462.5625). Is this violating any FCC rules and / or potentially creating any problems? Yes, I do have an active GMRS license.

Thanks in advance for any feedback!

WSEI687 Dale

Actually the lowest GMRS channel is 15: 462.5500. Channel spacing sequentially is 25kHz, but because of the interstitials (channels 1-7, and 8-14), the spacing within the band is actually 12.5kHz. Maximum deviation on the 462.* channels is 5kHz, if I recall. So I would, for example, listen on 462.5500 (channel 15). The channel width is 25kHz (+12.5kHz to -12.5kHz from 462.5500), so the actual GMRS band (including the full channel width) goes from 462.5375 to 462.7375, once you account for the bandwidth. And the same goes for the 467 portion of the band.

462.5625 is not a private channel. It's a channel that would overlap OUT of GMRS band by 12.5kHz. So you're actually asserting a privilege you don't have all the way down to 462.5250, which is clearly out of the GMRS band.

GMRS is channelized. You are only permitted (with your license) to transmit on the 22 channels, plus the 8 repeater channels with a type approved radio, and the reason type approved radios are required is so that people can't do stupid things like transmitting out of band or in ways that cause interference.

Let's say you decided that it would actually be more clever to select a frequency within the GMRS band, rather than one that falls outside of the band: 462.55625 (for example). What's the worst that could happen? Well from a technical standpoint, that means you've selected a frequency that falls exactly between channel 15 (462.5500) and channel 1 (462.5625). And because you have a channel width of 25kHz, and maximum deviation of +/-5kHz, you're overlapping two channels. You haven't created a private channel, you have caused interference to users on channel 1 and on channel 15.

There is NO space between the GMRS channels that would allow for you to transmit FM in a way that doesn't interfere with existing licensed users.

 

Now let's go out of the GMRS band. You've gone below the band; you're radiating below 462.5500. What's the worst that can happen? Look at the following chart, available on the FCC website:

image.png.72b7f48a0251bd71e7cc684d48dcc1f1.png

You see the long vertical bars named "Land Mobile" at 462.xxxx and 467.xxxx. Those are GMRS/FRS. Now do you see the shorter bars listed as both Land Mobile and Fixed? Those are LMR (business), and other licensed users. Your selection of a frequency that bleeds outside of GMRS causes interference to non-GMRS licensed users who pay for the licenses they have to use the frequency you're squatting on.

 

Let's look at that a little more closely:

image.thumb.png.2165853d04b82c623ef38794772fb031.png

Here, you can see exactly how the frequency is allocated that you're interfering on: Private Land Mobile, and Fixed Land Mobile - 460-462.5375. The lower half of your signal overlaps into the Private Land Mobile spectrum, and the upper half overlaps into the "Personal Radio" (FRS/GMRS) part of the spectrum. You are interfering with someone who has a license to use PLM up to that frequency.

 

You might say, "But I don't hear anyone." And that's probably true, but not hearing someone doesn't mean the frequency isn't allocated, and doesn't mean that your interference couldn't be harmful. What if it's a digital service that only transmits in time of dire need? Your FM transmission could stomp on a digital transmission that only happens once in a blue moon, but when it does happen, is of vital importance to someone.

 

You didn't get an amateur radio license. If you did, you would have had to take some tests that demonstrated you knew how to regurgitate answers that the FCC thinks are sufficient for you to behave mostly responsibly within the amateur bands. But even an amateur license doesn't give you permission to just pick a frequency anywhere you like and start transmitting. It limits you to the amateur bands, and asks you nicely to look at the band plan first for  any of those given bands.

 

Anyway, what you're doing has the potential of being harmful to someone who has a legitimate license. It also is harmful to GMRS users of channel 15, which you're overlapping onto. And it's illegal.

You should have bought a GMRS radio and stuck to GMRS channels.

Here are a couple more screenshots showing what's going on:

In this first screenshot I have a software defined radio set to 462.5500, with a channel width of 25kHz so we can see more clearly the width of a channel. You can see that 15 overlaps with 1.

image.thumb.png.f316f3aab0d9811684c1f6c185aecad7.png

Now in this second screenshot I'm going to show the frequency you selected: 462.5375:

image.thumb.png.cb9d0c35b83ea2684b9a0216d643608c.png

As you can see in this picture, that 25kHz channel spacing causes your channel to overlap part of channel 15 in the GMRS range. But it also puts you squarely on top of someone transmitting a digital signal exactly on the frequency you selected. Of course this is in my area. Your area will have different licensees and they will be using that frequency in some different way. But how do you think their digital signal (if that's what they're doing) is going to work out if you stomp on it with FM voice? This is why the FCC has rules, and has the power to fine you heavily for interfering with other licensed users. In this case it's not a case of "The FCC doesn't care about GMRS users." It's worse, because you're mostly interfering outside of the GMRS band. What you're doing doesn't fall under the GMRS rules; you're transmitting an FM signal on a band that you have no license for.

 

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