I've been meaning to work on figuring out reticulum on 7mhz ISM.
The big win would be NVIS type coverage, kinda like 40m js8 without a #hamradio license. Massive range with a single transmitter, hundreds of miles to global with the right atmospheric conditions.
The big downsides would be antenna size compared to 900mhz ISM like #meshtastic and much more coverage variability over the course of a day and day to day.
Might be better to run something like that is an NVIS. That way your main coverage area would be several hundred miles out, but it would be more predictable.
7mhz is nvis possible. Predictable 400 ish mile circle if I remember correctly. That is mostly at gray-line though. 7mhz will come and go depending on solar activity and time of day though. Roughly 40m band but ISM.
I had to check to make sure apparently NVIS can be used on 40 meters but it's at the upper range of what you would want to use to do so
Here's a cutout from what Nano-GPT.com told me.
"Ionospheric Conditions: The ionosphere's behavior can vary significantly with solar activity and time of day. During periods of high solar activity, the ionosphere can reflect higher frequencies, making NVIS possible on the 40-meter band. During the night or during solar minima, the ionosphere may not reflect 40-meter signals effectively."
I do 40M nvis all the time. Not nearly as close or good as 80, but 300-700 miles is normal for me on 40
I’ve been contemplating a wide area reticulum network for a while as well now so very interested to hear if you manage to get anywhere with this
