There was an off-list comment that I received suggesting that VHF is only line of site. I know that is what they teach in elementary communications classes, but it is not quite like that. There are various propagation modes that enhance the range, such as tropospheric ducting and aircraft scatter. Then power and antenna gain are everything. For example if you look here https://www.rsgbcc.org/cgi-bin/vhfresults.pl?Contest=VHF%20NFD&year=2023#sa and click the 144 tab about half way down you can see that the longest distance on 144MHz (ODX) is is up to about 1000Km. That is beyond LoS but way short of a transatlantic distance. These are highly optimised stations running at least 400W to a well sited antenna usually with a gain of over 20dB - ie an ERP of 40KW, and this is using SSB or CW which is better than FM over weak signal paths. A UV5 out of the box is 5W FM with a gain of close to 0db it has a useful range of about 20 miles depending on terrain. There are specialist modes that can do better but here we are talking of bandwidths of the order of a few 10s of bits per minute. There are some transatlantic VHF beacons that have been deployed. I am not sure if they have been received across the Atlantic yet, but if they have it is the result of a rare anomalous propagation event. The OP refers to DMRoIP. I am not sure what that is, but I think this is DMR VHF to a gateway and then connecting via the Internet. The UV5 cannot do DMR. The UV5 could connect to a data gataway and then onto the Internet but there is no way radios of its general type can make the long path across the Atlantic on its own as the reader would have been led to believe. There is also no need for AI to do multilink and load balancing there are “ordinary” technologies that can do that and are widely deployed. Best regards Stewart/G3YSX |
