DirecTV Pursues Ka-band for 'Ultra HDTV'

high-definition-digital.tmcnet.com ^ | March 15, 2012 | Julie Griffin

[Las Vegas Dave]

HDTV pings!

Interested in the HDTV ping list?
Please Freepmail me (freepmail works best) if you would like your name added to the HDTV ping list,
(approximately 375+ freepers are currently on the HDTV ping list).
The pinged subjects can be HDTV technology, satellite, cable, OTA HD reception (Over The Air with roof top or indoor antennas), Broadcast specials, Sports, Blu Ray/HDDVD, and any and all subjects relating to HDTV.

Note: if you search Freerepublic using the keyword "HDTV”, you will find most of the past HDTV postings.

LasVegasDave.

[eyedigress]

It means my Radar Detector will be going nuts all over the place.

[Michigan Bowhunter]

cool stuff....i install directv.

[FreedomPoster]

Yeah, I was wondering about that one as well. Or if police radar would create interference for nearby receivers.

[battlecry]

I would worry more about rain. I think Ka attenuation is even worse than K band.

[Regulator]

Rain fade attenuation can be mitigated by variable gain on the satellite. Routine control feature in ops center software.

Not eliminated, but mitigated. And with multiple satellites you have path diversity.

[InterceptPoint]

Ka band frequencies are higher than than Ku band. That makes it easier to get higher bandwidth in the key rf components of the system: antenna, amplifiers, converters and filters. Ground antennas can be smaller and that is also a plus. The penalty: probable higher atmospheric attenuation. And getting transmit power on the satellite will be harder but apparently DirecTV thinks they can handle that problem.

[toothless_elk]

I think he’s concerned about rain-fade on the downlink...

[eyedigress]

I have one of those fancy smanshy Cobras that pick up everything from K to LIDAR. If a cop is within a half mile it goes off. I could just imagine one of those bands being used as a video carrier.

[eyedigress]

Watch out for the Train Crossings at Kroger as well. :^)

[backwoods-engineer]

To the other side of the water hole (26.5 GHz) they go. I’ll have to check the atten chart, but I believe atmospheric attenuation is higher there, but they will make up for it with more gain in the same size antenna. It’ll even out, or pretty close.

[backwoods-engineer]

I think he’s concerned about rain-fade on the downlink...

Yeah, it'll be higher at Ka.

[X-spurt]

What came of broadband over powerline? TXU or whatever they call themselves today was going ot do it and suddenly backed out. Reportedly could get broadband + HDTV + phone.

[Terpfen]

It exists and you can buy it now, but it’s not very good.

[Tunehead54]

Our house is surrounded by tall trees - years ago we checked with the “dish” people and they said no way could we get reliable signal.

For people with dishes in the best locations - do they lose signal during storms/heavy rain? Just curious - sort of sounds that way ... out here in Florida that would seem to be a consideration favoring cable ... ;-)

[Hawthorn]

>> Ground antennas can be smaller and that is also a plus <<

Aren't you forgetting about the dipole factor? I mean, of course the dB gain could be the same with a smaller dish. But the actual signal strength, measured as microvolts across the terminals of the dipole, would vary inversely as a function of wavelength.

[Hawthorn]

According to ARRL, BOPL is basically dead. Hams and some other MW users fought it vigorously at every step of the way, but they probably had little effect on the regulators. What finally seems to have nailed the coffin is that BOPL technology just wasn’t cost-competitive in most places where it was tried.

[Hawthorn]

>> Our house is surrounded by tall trees - years ago we checked with the “dish” people and they said no way could we get reliable signal <<

They’re wrong. It all depends on how tall a tower you’re willing to install in your backyard!

[Hawthorn]

Correction to my earlier post:

The dipole factor means, for an antenna whose size is held constant as measured by wavelength, signal strength will vary inversely as a function of the freqency. (Just hope I got it right this time!)