GMRS Bandwith Question

[BabaDude77]

So I’m new to GMRS just got my license but have had radios and scanners for a long time. My question involves the bandwidth of the channels when programming them into the radio. I am using a Motorola XTS 5000 and usually set my channel bandwidth to 12.5(narrow band) but on MyGMRS it says the repeater bandwidths for GMRS is 20.0 so my question is which is correct and how should it be programmed. I’m having a real hard time hitting my local repeater in the next town over could this be the problem? Also have an XTVA and still can’t hit it often even while Mobil (and yes I understand it’s only 5 watts on high power) but I have no problem hitting a fire repeater some 20 miles away with the portable. Just wanted to see if the problem was my programming or maybe the location of the repeater is bad?

 

[rf_patriot200]

So I’m new to GMRS just got my license but have had radios and scanners for a long time. My question involves the bandwidth of the channels when programming them into the radio. I am using a Motorola XTS 5000 and usually set my channel bandwidth to 12.5(narrow band) but on MyGMRS it says the repeater bandwidths for GMRS is 20.0 so my question is which is correct and how should it be programmed. I’m having a real hard time hitting my local repeater in the next town over could this be the problem? Also have an XTVA and still can’t hit it often even while Mobil (and yes I understand it’s only 5 watts on high power) but I have no problem hitting a fire repeater some 20 miles away with the portable. Just wanted to see if the problem was my programming or maybe the location of the repeater is bad?

The low power Frs and Gmrs channels that are 462.5625 to 462.7125 are 12.5khz steps. and Repeater channels are 462.550 to 462.725 are 20khz. steps. I have a XTS 2500 FPP

 

[BabaDude77]

So just to be clear where it shows in CPS “Tx Opt Transmit Dev” should be set to 4.0khz and spacing of 20.0 kHz for repeater channels and treat line of site channels as narrow band ?

 

[nokones]

Unless the repeater owner states the repeater operates Narrowband, set your channels for 5 KHz (Wideband) emissions.

 

[rescuecomm]

By the FCC rules, FRS 2 watt radios with fixed antennas use narrow band deviation on all 22 frequencies. The GMRS branded radios can be either wide or narrow on the interstitial frequencies, but wide band on the repeater 462.550 to 462.725 outputs and 467.550 to 467.725 inputs. The seven FRS interstitial frequencies 467.5625, 467.5875 etc are 0.5 watts and narrow band.

I thought all split channels were by rule narrow band until I bought a couple of "GMRS" branded handhelds. They were wide band on everything except the FRS 467 mhz splits. I suppose you should set your XTS 5Ks to be interoperable with your friends, family, and team members radios on simplex. Repeaters should be wideband 20k unless otherwise noted. All five GMRS repeaters around here are wide band.

 

[rf_patriot200]

So just to be clear where it shows in CPS “Tx Opt Transmit Dev” should be set to 4.0khz and spacing of 20.0 kHz for repeater channels and treat line of site channels as narrow band ?

Wide band, 5.0 khz. Deviation and yes, 20khz. step size.

 

[nokones]

The GMRS UHF channels (450-470 MHz) modulation limits are either, narrowband with 2.5 KHz deviation and 12.5 KHz channel spacing, or wideband with 5 KHz deviation and 25 KHz channel spacing, depending on the GMRS channel. The CPS for most Motorola model radios deals only with deviation (emissions) and channel spacing settings and not bandwidths thus there is no setting for bandwidths. In the case with the XTS5000 radio, the OP will either select narrowband emissions meaning the deviation of 2.5 KHz and the channel spacing is 12.5 KHz or wideband emissions meaning the deviation of 5 KHz and the channel spacing of 25 KHz. Yes, the maximum channel bandwidth shall not exceed 20 KHz but there is no channel bandwidth setting in the CPS.

 

[jeepsandradios]

I have 2 banks in my APX. One is called Midland and is based on the Midland mobile and portable with all narrowband. Next bank is GMRS and is wideband simplex and repeater only. None of the FRS stuff. May be an option for you also.

 

[BabaDude77]

Thanks everyone lot of good info

 

[rescuecomm]

I have 2 banks in my APX. One is called Midland and is based on the Midland mobile and portable with all narrowband. Next bank is GMRS and is wideband simplex and repeater only. None of the FRS stuff. May be an option for you also.

That's what I need to do for my Icom F4061 radios eventually. The Ailunce HA1G has me covered for anything involving CERT or other civilian groups.

 

[BabaDude77]

The GMRS UHF channels (450-470 MHz) modulation limits are either, narrowband with 2.5 KHz deviation and 12.5 KHz channel spacing, or wideband with 5 KHz deviation and 25 KHz channel spacing, depending on the GMRS channel. The CPS for most Motorola model radios deals only with deviation (emissions) and channel spacing settings and not bandwidths thus there is no setting for bandwidths. In the case with the XTS5000 radio, the OP will either select narrowband emissions meaning the deviation of 2.5 KHz and the channel spacing is 12.5 KHz or wideband emissions meaning the deviation of 5 KHz and the channel spacing of 25 KHz. Yes, the maximum channel bandwidth shall not exceed 20 KHz but there is no channel bandwidth setting in the CPS.
View attachment 170676

Best explanation yet thank you , extra points for the visual aid 👌

 

[vagrant]