The most noteworthy thing I'm seeing in C band these days, is many customers formerly 100% reliant upon it shifting their traffic to newly built submarine fiber routes.
On Mon, Jul 6, 2020, 11:51 PM Denys Fedoryshchenko < [email protected]> wrote: > On 2020-07-07 08:32, Eric Kuhnke wrote: > > "no clouds" is overstating the effect somewhat. I've operated a number > > of mission critical Ku band based systems that met four nines of > > overall link uptime. The operational effect of a cloud that isn't an > > active downpour of rain is negligible. Continual overcast of clouds is > > not much of a problem at all, it's active rain rate in mm/hour and its > > statistical likelihood, climate parameters of the location. > > > > Yes, during rain fade events, current generation VSAT modems will drop > > all the way down to BPSK 1/2 code rate to maintain a link, with > > corresponding effect on real world throughput in kbps each direction, > > but entirely dropping a link is rare. > > > BPSK 1/2 is quite extreme. In my case it was 32APSK 8/9 at 36Mhz > transponder > (yes it was quite large antenna), ~140Mbit, so switching to 1/2 BPSK > will make it > ~16Mbit/s, which is pretty useless for telco purposes. > For corporate, end-users, with QoS - it can be ok, but still depends on > climatic zone. > Remember, it is not downlink only issue, but uplink too. And depends on > antenna elevation angle > as well. > Even for end-user it is not fun to have 1/10 of capacity, most likely > means unable to do > video conferencing anymore, for few days, just because it is few rainy > days. > And as Ku is often covering specific regions, often it means rainy days > for most transponder customers. > This is why in zones closer to equator, with their long-term monsoon, > C-Band was only option, > no idea about now. >
