Bad News for C Band from the FCC

harshness

harshness

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May 5, 2007
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Yes they are...same with sd and HD signals...no special transponder required...all happens at the uplink site
You're wrong.

First and foremost, the uplinks are at different radio frequencies than the downlinks so that means that a satellite is not an RF mirror.

From the "bent pipe" section of the Wikipedia article on transponders:
Wikipedia said:
Most transponders operate on a bent pipe (i.e., u-bend) principle, sending back to Earth what goes into the conduit with only amplification and a shift from uplink to downlink frequency. However, some modern satellites use on-board processing, where the signal is demodulated, decoded, re-encoded and modulated aboard the satellite. This type, called a "regenerative" transponder, has many advantages[example needed], but is much more complex.[citation needed]

Note the "shift from uplink to downlink frequency" part.

SD versus HD or MPEG2 versus MPEG4 is a matter of how they divide up the resultant carrier bandwidth (multiplexing). C-band versus Ku versus any other band is about the frequency of the carrier that the bandwidth rides on top of. I'm pretty sure you understand that antenna that tunes 4GHz must be different from an antenna that tunes 12GHz or 17GHz.
 
jayn_j

jayn_j

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Yes they are...same with sd and HD signals...no special transponder required...all happens at the uplink site

Sent from my SM-G950U using the SatelliteGuys app!
Except that receivers and transmitters are tuned to work at a certain frequency. Modern designs do have a digital signature which allows for broad changes in the frequency, but it is not infinite. Many older satellites are either working with a fixed frequency range or cannot adapt to a much higher frequency.

Add to this the antenna issue. Those antennas are definitely tuned to a small frequency range. Unless they were designed to work at multiple frequencies, trying to run them at Ku frequencies would drive the SWR to a high level as to be unusable.

Basically, unless the satellite was designed to operate at Ku frequencies, it is just so much space junk if this becomes law.
 
jayn_j

jayn_j

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All right guys lets knock off the trolling and back to topic.
Not sure why this is trolling. There seems to be a fundamental issue with understanding how signals are transmitted and received. I see this as education.

As a HAM, you understand, but obviously others don't
 
Titanium

Titanium

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Sorry, but this is not correct. It is not all or nothing. Satellites currently operating for C-band downlink frequencies would continue to be used within the reduced bandwidth throughout their lifespan.

Satellites launched in the past 20+ years for C-band frequencies will not be junk. A satellite has a bank of transmitters (this number varies between hardware designs), which are used to cover a specific range of the available bandwidth. If a portion of that bandwidth will not be used, the frequency is simply not transmitted on.

Example: Often, satellites transmit in the 3.4-4.7 or the 4.5 -4.8GHz ranges, but these frequency ranges are disabled if the satellite is operated from a slot which is not licensed for these frequencies.

Except that receivers and transmitters are tuned to work at a certain frequency. Modern designs do have a digital signature which allows for broad changes in the frequency, but it is not infinite. Many older satellites are either working with a fixed frequency range or cannot adapt to a much higher frequency.

Add to this the antenna issue. Those antennas are definitely tuned to a small frequency range. Unless they were designed to work at multiple frequencies, trying to run them at Ku frequencies would drive the SWR to a high level as to be unusable.

Basically, unless the satellite was designed to operate at Ku frequencies, it is just so much space junk if this becomes law.
 
johnnynobody

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Yes they are...same with sd and HD signals...no special transponder required...all happens at the uplink site

Not true. There's an uplink freq that's amplified and converted to a different downlink freq.


"Nearly all C-band communication satellites use the band of frequencies from 3.7 to 4.2 GHz for their downlinks, and the band of frequencies from 5.925 to 6.425 GHz for their uplinks."
 
907TECH

907TECH

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Aug 29, 2018
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Except for the guard bands of 2 Mhz. at the top and bottom of each transponder. So 3702 to 4198 downlink, and 5927 to 6423 on uplink. So "usable" BW of 36 Mhz on each transponder.
 
Cham

Cham

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What's happening with the 3.5-3.7GHz portion of the downlink band? Is it taken up by 5G as well?
Maybe that portion of band is not considered satellite downlink in NA so they don't mention it...
 
VictoriaFTA

VictoriaFTA

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Sep 20, 2018
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How could a YooToo distribution transition to IP be the first casualty? This is only the FCC chairman's recommendation with no auctions or negotiations in play.

No Chicken Little... the sky is not falling. LOL

Seems we have another victim: the NESN networks mux that was on AMC-11 has been dropped and I don't see a replacement uplink for them anywhere.

NESN joins the Spectrum SportsNet mux on Galaxy 17 and the NBC SportsNet Northwest channel on Galaxy 14 in the growing list of regional sports networks that have dropped C-band for distribution entirely this year and gone to fiber distribution only.

How many more networks have to stop using C-band for distribution in favor of going fiber only before you realize that the sky is falling?

It's starting with the regional sports networks as they have fewer providers who carry them and it will continue as more niche channels decide to go fiber only. In time even the big channels that are carried by tons of providers will start going dark on C-band as every MVPD will have sufficient fiber infrastructure to receive them all.
 
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Titanium

Titanium

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Distributing via fiber has been an option for 15 plus years. For some distribution models IP distribution makes sense and for other services satellite distribution does. I don't understand why someone like yourself, who has observed services come and go over the years now views a channel changing distribution models to IP to be a sign that the sky is falling and satellite distribution is ending?

In your last post you indicated that the YooToo service was changing to IP due to the FCC statement in support of an auction... This is what I responded to...

How many new channels need to be added in a month for you to realize that services come and services go?

Don't Be Like Chicken Little
 
N5XZS

N5XZS

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Look at a bright side, there's a droid has successfully refueled a old bird just few days ago and your going to see more in the future!:bow

Geostationary satellite birds will be around for a long time till end of time "Talking Eons from now" regardless of C or Ku bands or whatever.


There are tons of signal out there for you to tune in legally, stop crying about it sheesh!:hatsoff

Have fun TV DXing!:bow:hatsoff
 
B

Brct203

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Dec 24, 2016
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I'm not too worried about the satellites that serve the US/Canadian markets as the services will move to the remaining part of the C-Band spectrum. Sure some will go to IP instead but like Brian said, IP does not necessarily make sense in all cases and satellite is still a viable solution. There's also the option of moving to Ku. Sure there's rain fade, but if it's good enough for the PBS mux, it must be reliable enough for others too.

my biggest worry is that C-Band satellite services will continue like they are now on Atlantic satellites, and that we will no longer be able to receive parts of them because of terrestrial interference from 5G.
 
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calmeidajr

calmeidajr

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Well at least ku band will be here for awhile sucks but what can you do
 
johnnynobody

johnnynobody

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I'm not too worried about the satellites that serve the US/Canadian markets as the services will move to the remaining part of the C-Band spectrum. Sure some will go to IP instead but like Brian said, IP does not necessarily make sense in all cases and satellite is still a viable solution. There's also the option of moving to Ku. Sure there's rain fade, but if it's good enough for the PBS mux, it must be reliable enough for others too.

my biggest worry is that C-Band satellite services will continue like they are now on Atlantic satellites, and that we will no longer be able to receive parts of them because of terrestrial interference from 5G.

When I worked on the NBC Ku band project back in the mid-80's, things worked fine unless the antenna deicing units failed. I worked on some Ku-band FedEx equipment also. Of course, the primary antennas were a minimum of 6 meters with a 3.5 meter backup and they were solid. I doubt many of us could install such a large antenna in our back yard and the cost would be prohibitive. I'm not sure how well a 10 or 12 footer would work on Ku during a rain storm. But it wouldn't work too well with snow or ice accumulation. And it was really difficult to align a 6 meter dish because of the tight beamwidth. If you blinked while panning you probably would miss the peak on the spectrum analyzer or meter.
 

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