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GMRS tone codes between radio manufacturers

Guest Murf'n'surf

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Guest Murf'n'surf

Hey guys and gals!  New to GMRS and tasked with setting up a Rugged Radio GMR45 and Back Country BC Link 2.0 walkies.  As far as documentation goes they both use the same tone codes between the 2.  My problem is that both radios don't seem to  TX and RX on every tone code that I am trying.  When using the straight whole number channel for example 17, they both RX and TX just fine.  If I try any tone code with the GMR45 set on T SQ or SQ DCS(which I'm reading are for TX and RX) there is only TX (usually) on the GMR45.  The BC Link radios RX the GMR45 but the GMR45 does not RX the BC Link walkies.  Sorry if I am rambling and confusing anyone!   

Bottom line.....why cant I use tone codes between the radios? What an I missing?


Random info I see from the Rugged GMR45 radio programmer tool:

 462.60000       Simplex    FM Narrow    C 17    T Sql    100.0 Hz    100.0 Hz      

I can change the Simplex to Plus and the FM Narrow to FM

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Not being familiar with your specific radios, here is some general info & considerations.

Unless you are using a repeater between you radios, you will want leave then in simplex mode.  

You will be better off (IMO) changing to wideband instead of narrow.  If the only options are "FM" or "FM Narrow" then select FM.

Do the BC link radios receive each others Tx on the 100.0 Hz tone?

Make sure both GMR45 and BC link are in simplex mode, wideband, and the same Sql Tone. Make sure all other variable remain the same as when they work without the tones and try again. (power level, location, obstructions, etc.) 

Changing from Narrow to Wide band might solve the problem, but if it doesn't there are plenty on helpful operators in this forum.

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The BC Link web pages and manual aren't firm on it, but from the lack of mention of a GMRS license it reads, to me, that these are (2017 FCC) FRS radios, and only operate on 12.5kHz... So using NFM on the GMR45 might be reasonable (otherwise the difference between 12.5kHz and 20kHz [FCC spec for GMRS] may result in some odd sounding voices or clipping). cf: https://www.ecfr.gov/current/title-47/chapter-I/subchapter-D/part-95/subpart-B?toc=1

The GMR45, OTOH, does need a license. Normal GMRS bandwidth is 20kHz on (using the FCC consolidated channel scheme) 15-22 (the original GMRS channels -- from back in the day when a license was only authorized TWO of the channels) AND on GMRS interstitial channels 1-7 (which were available to all GMRS licenses, but at a low power limit, because they were stuck between each primary channel and overlapped). 8-14 weren't part of the GMRS channel line-up -- they were originally FRS (0.5W/12.5kHz) channels snuck between GMRS repeater input frequencies. They are still limited to 0.5W NFM. cf: https://www.ecfr.gov/current/title-47/chapter-I/subchapter-D/part-95/subpart-E?toc=1

I'd concur with the prior respondent: first ensure all radios interoperate with no tone squelch. (Set the GMR45 to its lowest power mode -- and maybe walk a ways down the street; it may be putting out so much power that it is overloading the front-ends of the BC-Link units).

Then, verify that the BC-Link units work when both are set to the same channel and CTCSS code (these are not really "privacy" codes -- any radio /not/ configured for CTCSS can hear you; they just mean you don't hear others unless they are set to the same code). The handhelds appear to be full CTCSS encode/decode. The mobile has options for tone encode only (sometimes used to get into a repeater, but the repeater does not send a tone back) and encode/decode (T vs TSQ on display).

Don't try to use both CTCSS and DCS at the same time (the handhelds don't do DCS). CTCSS is just a subaudible continuous single tone. DCS is a serially encoded "number" that has to be matched by the receiver..


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