Those are almost certainly C band dishes, all the downlinks that cable companies receive are C band which is affected far less by rain fade so you don't need a NASA sized dish to avoid rain fade.
In a hotel, how does 41 directv channels in analog work
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Those are almost certainly C band dishes, all the downlinks that cable companies receive are C band which is affected far less by rain fade so you don't need a NASA sized dish to avoid rain fade.
I sort of remember measuring the difference in gain between a Slimline and Alaska/Hawaii dish and it came in around 5dB. As a general rule, double the size of a dish and the gain goes up about 6dB. I designed and built the head ends for two DirecTV uplink centers feeding hundreds and hundreds of receivers and specified Alaska/Hawaii dishes to give more headroom and rain fade margin throughout the system.
On the fuzzy pictures and adding more amplifiers, the problem might be too much amplifier. The analog signal is amplitude modulated and you have to be very careful on amplifier gain and cable loss to the next amplifier and you can only do that so many times before the signal is ruined beyond repair. 40 or 50 carriers on a closed system all amplitude modulated and needing cascaded amplifiers is a recipe for an IMD disaster.
I remember seeing an old post on dbstalk where someone set up the AK/HI dish and measured the difference between that and their Slimline. But maybe they didn't get it fully tweaked, or the variability between LNBs got them.
I knew the theoretical gain should be 5-6 db, I was just going by the only data point I've ever seen. Now I have two, and from someone who knows this stuff far better than whoever did that test on dbstalk
Either way, the attenuation from rain fade, especially in Ka, is so massive in even an ordinary supercell thunderstorm an extra 6 db isn't going to make any difference. For ordinary "rain" sure if you were on the margin before a half dozen db will save you.
I had access to the prototype Alaska/Hawaii dishes and the new at the time Slimline dish and was able to make exact C/N comparisons, I just wish I had kept the data from that. The reason I used the larger Alaska/Hawaii dishes was to provide a little more C/N for rain fade on a huge distribution system at a couple of DirecTV uplink sites feeding lots of receivers. I also needed the best C/N into the system to make up for degradation through amps and equalizers and a mile of coax. In So Cal the Alaska/Hawaii dishes definitely rode through rain fade where we had an occasional but rare outage off a Slimline at the same site.I remember seeing an old post on dbstalk where someone set up the AK/HI dish and measured the difference between that and their Slimline. But maybe they didn't get it fully tweaked, or the variability between LNBs got them.
I knew the theoretical gain should be 5-6 db, I was just going by the only data point I've ever seen. Now I have two, and from someone who knows this stuff far better than whoever did that test on dbstalk
Either way, the attenuation from rain fade, especially in Ka, is so massive in even an ordinary supercell thunderstorm an extra 6 db isn't going to make any difference. For ordinary "rain" sure if you were on the margin before a half dozen db will save you.
The distribution system fed by the Alaska/Hawaii dishes was very busy starting with a huge galvanized structure bolted to the side of the concrete building to hold the dishes since the facilities people couldn't be convinced a non pen mount on the roof would not hurt the roof. So it cost a fortune in time and labor to mount these structures on the building to hold the two Alaska/Hawaii dishes and about a 1.2m dish for monitoring some DirecTV Latin America stuff. Anytime we had to get access to the dishes took a manlift and a lot of cuss words. The dishes all fed a custom front end using components from Sonora, their polarity locker and they factory modified a bunch of 250-2150MHz AGC amps for me with an alarm output port since the system was redundant and the first line amps could catch a failed LNB or a failed line amp then switch to an entire spare set of dishes amps and power supplies.
I thought I had better pictures of the system using Alaska/Hawaii dishes but all I can find is a picture of one of the custom front ends I was in the middle of assembling including designing and building the chassis, quick replicable cards that held the amps and other components and the alarm switching circuitry. It was all powered by hi reliability Acopian power supplies. The front of the rack chassis had status lights and directional couplers for monitoring RF levels. I would not have gone through all that if a consumer grade Slimline was feeding things. The picture below is one of the power supply/amp chassis going together and there were two of these chassis at each site plus some banks of coaxial relays to feed the building distribution.
I thing the catch phrase in a google search for dish network smartbox would give some interesting hits.
Have fun!
Have fun!
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