CHIRP

Richard Perlman wrote:

This feature request is to address an undocumented (in the UI) behavior. On the GMRS-V1 radio, the first 15 memory locations (0-14) operate simplex (offset = 0) and locations 15 to 22 operate with a +5mHz offset. Then, locations 23 to 127 are all simplex. This is a limitation of the radio, no doubt required to gain thorpe acceptance. However, because it is not visible to the CHIRP user it is easy to create problems. For example: I had a request to set GMRS-1 to location 1 so the numbers lined up. I did that by moving all the locations down by one, leaving location 0 open. However, when the user tried to transmit simplex on location 5, they were actually using an offset of +5mHz.

The RX and TX frequencies of the GMRS-V1 channels 0 through 22 are fixed in the firmware and cannot be edited or relocated. Channels 0 through 6 (the shared FRS channels) are also bandwidth fixed to NARRow. This was a FCC requirement in order to achieve Part 95A certification.

To get channel 0 to look like channel 1, you will have to use the channel Name to call it channel 1 and set the Memory Display Format (MDF-A or MDF-B) to NAME (which that is the way the GMRS-V1 comes from the factory).

The user could not transmit on channel 5 with a +5 MHz offset because it is impossible to change the TX frequency. The channel 5 simplex frequency of 462.6875 MHz is fixed at the factory. If you edit any of the "fixed" frequencies and upload them to the radio, when you download from the radio back to CHIRP the original factory frequencies will again be displayed.

The frequency assignments for channels 0 through 22 are documented on page 32 of the GMRS-V1 user manual.

The suggested fix would be to add a dummy column for Duplex and offset. The values would be fixed (grayed out in the UI). However, the presence of this information would make the behavior of the radio clear to the programmer.

The Duplex and Offset columns are used to edit TX frequencies. The TX frequency for memory rows 0 through 22 are fixed and cannot be changed, so there is no TX frequency to edit in these channels. Memory rows 23 through 127 are receive only, so there is no TX frequency to edit in these channels. So there is absolutely no need to have a Duplex or Offset column because there are no TX frequencies in this radio that can be edited. Only the columns that can be user edited are included in this driver.

Jim KC9HI

I think, perhaps, you may have misunderstood my feature request. I do understand that the transmit offsets are fixed in the firmware. What I was suggesting were pseudo columns (i.e. non-editable) with grayed out values. The point of these columns and values would be to make clear to the user how a frequency entered for the location would behave.

The comment about the location matching the channel was just to show an impact of not having the UI make the behavior clear. The complaint presented to me was that the location number, which is always visible for MDF-A & B) and therefore does not match-up - channel 1 is at location 0, etc. I am not requesting anything to change that. Only noting that if the UI had made clear how the locations would operate (i.e. fixed simplex or offset) I would not have made the error I did.

Right now if the mode is changed on channels 0-6, a message pops up that says only NFM is supported. Only the RX and TX frequencies should be immutable (they can't be changed in the radio). Selective squelch and power are still supported.

The user can enter frequencies into the remaining channels (23-127) but they are TX inhibited (RX only).

The normal UI does hide the Duplex and Offset columns since they are not editable by the user. But without them you don't know that channels 15-22 are programmed (at the factory) as repeater channels (that is what Richard is pointing out). If the Duplex and Offset columns were turned back on but made immutable, I think that would make Richard happy.

It also needs to block changes to the Frequency column for channels 0-22.

I'm not sure how to do these things or I would have already done it. ;-)

Jim

Since there seems to be no issues with the change, is there anyone who would kbnnow how to do it?