On Sat, Jun 3, 2017 at 5:51 AM, Rich Messeder NE1EE@hotmail.com wrote:

For each new release of CHIRP, should I read a new file from the radio, open the latest saved file, and copy memories to the new file? The issue prompting this is that I wonder if CHIRP img files are always backward compatible? Sometimes compatible? What is the 'best practice'?

Chirp img files are a raw memory dump from the radio. They may change with radio firmware version, but they won't change with Chirp versions. In fact, if you download from the radio, then immediately save the img, Chirp will not have touched the data at all. It will be a bit-for-bit clone of the radio's memory.

New Chirp versions my *interpret* the img differently. If we find there was a bug in how a radio's data was being interpreting, a new version of Chirp will contain a bug fix to interpret the data accurately. This would not necessitate downloading from the radio again (unless the earlier Chirp version clobbered the file due to a particularly horrendous bug).

I tend to make changes to my radios "in the field". I might add a channel from the front panel, change a scan mode, etc. To not lose these settings, my "best practice" is to always Download From Radio before editing with Chirp. This makes sure any changes I make with Chirp are on top of my "field" changes, not replacing them.

Tom