Agreed - I was trying to figure out if the channel/frequency mapping is a Part 95E requirement. If it is, I cannot find it. The only place I can find a reference with channels is under Part 95B, "FRS Channels," but the equivalent (?) regs for GMRS simply state the frequencies allowed, which makes sense. Some links below.
47 CFR Part 95B §95.563 "FRS Channels" - https://www.ecfr.gov/current/title-47/chapter-I/subchapter-D/part-95/subpart...
47 CFR Part 95E §95.1763 "GMRS Channels" - https://www.ecfr.gov/current/title-47/chapter-I/subchapter-D/part-95/subpart...
Thanks, Chris
On Wed, Feb 23, 2022 at 10:37 AM Nigel A. Gunn G8IFF/W8IFF nigel@ngunn.net wrote:
OK Chris. In most radios that come pre-programmed by the manufacturer, as opposed to the random channels that a manufacturer seems to leave in there after testing, I believe they are locked by the firmware in order to comply with a country's frequency allocations and get type approval in that country. Don't know if the FCC insists on that.
On 23/02/2022 13:27 Chris Romp chrisromp+chirp@gmail.com wrote:
Hi Nigel,
In the case of the RB26 that doesn't appear to be true: I have one in my hands that's configured for repeater 18 (625) on the radio's channel 1, and they seem perfectly happy to radio clone that configuration to other units. It may be that other radios do enforce it in the firmware (e.g. BTech GMRS V1, though I haven't tested that).
Jim KC9HI explained that CHIRP is doing this because that's how the OEM software behaves in the case of the RB26. I've since pulled down their (terrible) software and verified that, and emailed Retevis to ask why (not optimistic I'll get a useful response).
Thanks, Chris KN6LEH
On Wed, Feb 23, 2022 at 10:16 AM Nigel A. Gunn G8IFF/W8IFF nigel@ngunn.net wrote:
Nothing to do with Chirp. The radio's firmware doesn't allow them to be changed.
On 23/02/2022 12:44 Chris Romp chrisromp+chirp@gmail.com wrote:
Thanks, Jim, for that info. I've reached out to Retevis to see if they have any input. Would it basically be a requirement for CHIRP to support assigning any GMRS frequency to any channel for Retevis to change their OEM software, even if the radio supports it?
Thanks again, Chris
On Mon, Feb 21, 2022 at 6:08 PM Chris Romp chrisromp+chirp@gmail.com wrote:
Hello,
I have a question about how CHIRP handles GMRS radios, e.g. BTech GMRS V1 and Retevis RB26. I've noticed that CHIRP enforces that GMRS channels follow the FRS channel number and frequency pairings, e.g. Channel 1 is 462.5625, Channel 18 is 462.625, etc. I've been trying to find in the FCC regs if this mapping is a requirement of GMRS operation. The only place I've found the channels spelled out is on 47 CFR Part 95B ?95.563 "FRS Channels" (link), but GMRS seems only to specify the frequencies and bandwidth which may be used via Part 95E ?95.1763 "GMRS Channels" (link). It's entirely possible that I've missed the clause requiring this mapping, and I am not a lawyer, so apologies if I've overlooked it.
When I am programming a GMRS radio, I don't always want what my family refers to as our "channel 1" to be 462.5625. Likewise I may want to set up different repeaters that may use the same frequencies, but different tones (especially on radios where I cannot edit the tone from the radio itself) I am able to program the RB26 to accept an alternate GMRS-legal frequency with a little trickery, so there does not seem to be a firmware restriction enforcing this and it hasn't bricked my radio (yet).
Would it be possible for CHIRP to accept GMRS-legal frequencies in any channel slot, and not require the FRS channel-frequency mapping?
Thank you, Chris Romp
The BTECH GMRS-V1 channel assignments are in firmware. Even if CHIRP would let you put in different frequencies, it wouldn't make any difference. Channel 1 will always be 465.5625 MHz.
The Retevis models are programmed to match how the OEM software behaves. Some of the newer Retevis models let you program the GMRS frequencies in the radio however you please.
Jim KC9HI
chirp_users mailing list chirp_users@intrepid.danplanet.com http://intrepid.danplanet.com/mailman/listinfo/chirp_users This message was sent to Nigel Gunn, W8IFF at nigel@ngunn.net To unsubscribe, send an email to chirp_users-unsubscribe@intrepid.danplanet.com To report this email as off-topic, please email chirp_users-owner@intrepid.danplanet.com
Nigel A. Gunn, ///shoulders.outwards.resolutions tel +1-937-971-0366 Amateur Radio G8IFF W8IFF and GMRS WRBV701, e-mail nigel@ngunn.net www http://www.ngunn.net
Nigel A. Gunn, ///shoulders.outwards.resolutions tel +1-937-971-0366 Amateur Radio G8IFF W8IFF and GMRS WRBV701, e-mail nigel@ngunn.net www http://www.ngunn.net