Noob General Questions

[IndyGMRS]

I am a newbie and have some general questions.  Would any of you care to weigh in on the following questions:

1. I am aware of the standard 22 channels plus 8 repeater channels (frequencies, power, bandwidth).  Is it allowable to add an offset if the resulting Tx frequency is a standard GMRS frequency (so, half duplex)?

2. There is no standard for PL tones on the channels, right? Is a standard practice for different manufacturers of bubble-pack radios to set their channels up differently in regards to PL tones?

3. If a manufacturer allows for a scramble mode (beat shift, ie. frequency shift) instead of, or in addition to PL tones, could this take the frequencies outside of the allowable bandwidth?

4. I understand that HAM radios are not supposed to be used for GMRS.  If a GMRS radio can have the channel setups (other than PL codes) changed, is it really a GMRS radio?

5. Another way of asking #4 is...are GMRS radios allowed to have aspects of channels setups (except PL codes) customized? Does this technically make it a HAM radio in the FCC's eyes?

6. How many people just take Baofeng radios (Radioddity, Tidradio, inexpensive Chinese radios, etc.) and program them for GMRS? What effect does this have on others using GMRS?

 

Thanks for your input!

[SteveShannon]

1. So you are asking about transmitting on one of the channels not set aside for transmitting to repeaters and receiving on another. Like 462.550 and 462.675?

There’s no prohibition against that but it needlessly ties up two channels. 

[SteveShannon]

2. The frequencies used for CTCSS tones are mostly standard but some radios don’t have all of them. 

[Socalgmrs]

9 minutes ago, IndyGMRS said:

I am a newbie and have some general questions.  Would any of you care to weigh in on the following questions:

1. I am aware of the standard 22 channels plus 8 repeater channels (frequencies, power, bandwidth).  Is it allowable to add an offset if the resulting Tx frequency is a standard GMRS frequency (so, half duplex)?

2. There is no standard for PL tones on the channels, right? Is a standard practice for different manufacturers of bubble-pack radios to set their channels up differently in regards to PL tones?

3. If a manufacturer allows for a scramble mode (beat shift, ie. frequency shift) instead of, or in addition to PL tones, could this take the frequencies outside of the allowable bandwidth?

4. I understand that HAM radios are not supposed to be used for GMRS.  If a GMRS radio can have the channel setups (other than PL codes) changed, is it really a GMRS radio?

5. Another way of asking #4 is...are GMRS radios allowed to have aspects of channels setups (except PL codes) customized? Does this technically make it a HAM radio in the FCC's eyes?

6. How many people just take Baofeng radios (Radioddity, Tidradio, inexpensive Chinese radios, etc.) and program them for GMRS? What effect does this have on others using GMRS?

 

Thanks for your input!

1.no

2. Yes there are charts that show pl tones used for different bubble packs. 
 

3. No. Gmrs is not a band width it is 22+8 specific frequencies (channels)

4.a “gmrs” type accepted radio is certified by the fcc so if it’s certified it’s a gmrs radio. If it’s not certified then no it is not a gmrs radio

5. Sam as above.  As long as a gmrs radio only transmits on the 22+8 frequencies and has a fcc cert then it is a gmrs radio

 

6.many people do and it has zero effect on any one.  A radio is a radio.  Just some are certified and some are not.  No one will ever know if you are on a uv5r or a woxoun kg-uv9g and they all transmit the same distance. 

[SteveShannon]

3. Scrambling isn’t blessed by the fcc regulations but neither should it result in an FM frequency shift outside of the bandwidth allotment. 

[SteveShannon]

4. It depends on what’s changed and what you mean by no longer a GMRS radio.

5. No

6. Many, maybe most. 

[SteveShannon]

12 minutes ago, WRXP381 said:

3. No. Gmrs is not a band width it is 22+8 specific frequencies (channels)

But each channel has an allotted bandwidth. 

[dosw]

1 hour ago, IndyGMRS said:

I am a newbie and have some general questions.  Would any of you care to weigh in on the following questions:

1. I am aware of the standard 22 channels plus 8 repeater channels (frequencies, power, bandwidth).  Is it allowable to add an offset if the resulting Tx frequency is a standard GMRS frequency (so, half duplex)?

2. There is no standard for PL tones on the channels, right? Is a standard practice for different manufacturers of bubble-pack radios to set their channels up differently in regards to PL tones?

3. If a manufacturer allows for a scramble mode (beat shift, ie. frequency shift) instead of, or in addition to PL tones, could this take the frequencies outside of the allowable bandwidth?

4. I understand that HAM radios are not supposed to be used for GMRS.  If a GMRS radio can have the channel setups (other than PL codes) changed, is it really a GMRS radio?

5. Another way of asking #4 is...are GMRS radios allowed to have aspects of channels setups (except PL codes) customized? Does this technically make it a HAM radio in the FCC's eyes?

6. How many people just take Baofeng radios (Radioddity, Tidradio, inexpensive Chinese radios, etc.) and program them for GMRS? What effect does this have on others using GMRS?

 

Thanks for your input!

1) So, transmitting on one simplex channel, and receiving on another. 2x the opportunity for interfering with other users, or being interfered with. I would think that using the standard repeater channels is more reliable.

2) Midland, as an example, has a crossreference guide in its instruction manuals that identifies which tone number matches which actual tone. I have found that the Midland PL tone numbers are at least largely compatible with the PL tone numbers for my old Motorola FRS radio. Other manufacturers may vary, and hopefully would publish their crossreference. And of course some manufacturers don't use numbers, but instead just let you pick from actual tone frequencies.

3) I have an old Motorola FRS that has a scramble mode that is compatible with other Motorolas with the same feature, from the same era. But I don't think that scrambling on FRS or GMRS are allowed under current FCC rules, so there aren't any radios being manufactured today that are FRS or GMRS compliant that offer scrambling. The feature has mostly disappeared. The bandwidth for FRS is something like 12khz, and 20khz for GMRS except for channels 8-14 which remain 12khz. I don't think the old scrambling modes would shift outside of the narrowband range, but one would have to test to be sure. And since it's pretty rare to find an old unit that had that feature, it's rather moot.

4) The FCC seems only to approve a radio for GMRS if it can only transmit on GMRS frequencies. Some can be unlocked, or switched to other modes, though. But the unlocking is mostly an undocumented "feature". Ham radios aren't approved for GMRS, and GMRS radios can only transmit on GMRS. On the other hand, nobody's looking over your shoulder as long as you're observing the rules of the road for the service you're transmitting in. In other words, it's pretty much impossible to know that you're using a UV-5r ham radio to transmit on GMRS, and unless you're creating a scene, nobody's going to care.

5) GMRS radios can receive whatever frequencies the manufacturer wants to allow it to receive. But they must only be configurable for transmission on GMRS frequencies.

6) No way of knowing how many. Probably lots. Get your GMRS license, program whatever radio you want to correctly transmit on GMRS (correct bandwidth, correct center frequency, correct power level, etc.) and use it for that purpose. You'll possibly be in violation but undetectably so. If you're being a good GMRS citizen in every other way, you'll already be a step ahead of the kiddies playing with blister pack GMRS radios.