Questio about DirectV's new Ka Band Satellites

jim6201 · 03-30-2005, 04:50 PM

I understand Directv is all set to launch a bunch of Ka band satellites for its HD expansion. Ka band, as most of you know, is at a much higher frequency band than the Ku band currently used by Directv. My understanding is that Directv will position these new satellites near the existing Ku band satellites so that user satellite dishes will not have to be repointed to receive signals from the new satellites.
My question is: User dishes will of course operate at Ka band, but will have a much narrower beamwidth. The average user dish will be correctly pointed at Ku band frequencies, but will be mispointed at Ka band frequencies (the beamwidth is much narrower at Ka band).
How will Directv deal with this issue?

**rbinck** · 03-30-2005, 06:02 PM

I must admit that is above my pay grade. Have to wait and see,I guess.

Then there is the question of LNBs and multiswitches, etc.

What is the freq range of Ka band anyway?

calicogang · 03-31-2005, 12:15 AM

That's by me also. I will e-mail a friend of mine about KA birds. Will post his answer as soon as I receive it.

hdtv4me2 · 03-31-2005, 08:24 AM

The Ka-band of frequencies is generally in the 20 to 30 Ghz range. Directv has already announced that a new dish would be required to receive the new Ka-band feed. The new dish is required since, as pointed out, the old dish's beamwidth would be narrower therefore harder to point and the new LNB would need to be able to operate in the higher frequency range.

jim6201 · 03-31-2005, 06:24 PM

I believe the fact that Directv plans to change the satellite dishes solves my problem. The dishes will be smaller because of the higher frequency band used and, as was pointed out, new LNBs will also be needed because of the new frequency band. So it seems that we will be getting new HD receivers and new satellite dishes.

**rbinck** · 03-31-2005, 08:23 PM

What about the RG6, I wonder?

RG6 goes up to about 1 Ghz.

DTV TiVo Dealer · 03-31-2005, 10:57 PM

The antenna dish LNB, (Low Noise Block) amplifies the signal and beats down the KU frequency to 900-2150 mHz so it can run on coax. BTW RG6 coax can support up to 2200 mHz with very little degradation. So the coax is only transporting the MPEG-2 data stream at 900 - 2150 mHz.

DIRECTV will upgrade all HD customers with a new .66 meter dish with 5 LNBs, 3 KU receiving the current MPEG-2 101/110/119 satellites and 2 LNBs looking at the new KA MPEG-4 birds located at 99/103 degrees in the orbital slot. The 99 degree SPACEWAY 1 KU satellite is launching this week and the 103 degree KU SPACEWAY 2 satellite will go up later this year.

-Robert

beatboy77 · 04-01-2005, 02:14 PM

Robert,

So if I wanted to get ready for the Directv MPEG-4 Upgrade, should I run a 5th RG-6 cable from where my dish is mounted outside to where I will have the HMC?

Thanks,

Josh

**rbinck** · 04-01-2005, 08:09 PM

I was going by Belden's tables that stop at 1 Gig. Shows between 6-8db loss per 100'. That beating down the freq. explains it. Thanks.

DTV TiVo Dealer · 04-01-2005, 08:31 PM

Quote:

Originally Posted by beatboy77

Robert,

So if I wanted to get ready for the Directv MPEG-4 Upgrade, should I run a 5th RG-6 cable from where my dish is mounted outside to where I will have the HMC?

Thanks,

Josh

As MPEG-4 becomes available in every DMA, DIRECTV will be upgrading all HD customers’ dishes and HD receivers. They will run all of the coax required for the HMC. If you want to do it yourself, you are correct, 5 coaxes would be perfect, and one coax will be used for OTA.

-Robert

hdtv4me2 · 04-02-2005, 08:09 AM

So what are we to expect from D* tomorrow regarding the Yes channel?

hdtv4me2 · 04-03-2005, 08:12 AM

I see that channel 95 is showing Yankees/Red Sox game at 8:30 PM EDT. Anyone know who is eligible to watch it?

beatboy77 · 04-03-2005, 10:19 AM

Go Sox!!!!!!!!!!!!!!!!!!!!

jim6201 · 04-03-2005, 05:48 PM

Robert,

I appear to missing something here. Why do you need 5 coax feeds?
I have 4 coax feeds going to my main TV setup. Two coaxes feed my Standard Definition Tivo receiver, the third coax feeds my HD receiver, and the fourth coax feeds OTA signals to my HD receiver. My understanding is that unless I add another satellite receiver or upgrade my HD receiver to HD Tivo, I will not have to do any more coax installation for the Ka band system. I will have to swap my HD receiver for a new MPEG-4 capable receiver and install a new satellite dish.
Do I have this straight?
Thank you, Sir

Tony R · 04-03-2005, 07:56 PM

Is it a known fact that the existing oval antennas will be replaced with 66 cm antennas? Dropping the gain of the antenna for SD services is not a good idea. That means lowering the outage threshold during rainy weather. The beamwidth issue isn't so significant. The -3dB beamwidth formula is: signal beamwidth x efficiency of antenna reflector (%) / diameter (meters). The signal beamwidth is calculated by: 300/frequency (MHz). 300/30,000=.01 degrees. .01x60% (typical efficiency rating/.8. The difference is between .75 and .9 degrees. It seems to me that optimizing the feed to operate efficiently at both bands would be difficult since the focal point will be different for the two wave lengths. It would seem to make much more sense to have separate antennas for the DBS and Ka bands to prevent compromising performance between the two.

03-30-2005, 04:50 PM	#1
jim6201 My plasma is High Def. Join Date: Jun 2004 Posts: 9	Questio about DirectV's new Ka Band Satellites I understand Directv is all set to launch a bunch of Ka band satellites for its HD expansion. Ka band, as most of you know, is at a much higher frequency band than the Ku band currently used by Directv. My understanding is that Directv will position these new satellites near the existing Ku band satellites so that user satellite dishes will not have to be repointed to receive signals from the new satellites. My question is: User dishes will of course operate at Ka band, but will have a much narrower beamwidth. The average user dish will be correctly pointed at Ku band frequencies, but will be mispointed at Ka band frequencies (the beamwidth is much narrower at Ka band). How will Directv deal with this issue?

03-30-2005, 06:02 PM	#2
rbinck Administrator Join Date: Apr 2004 Location: Katy, Texas Posts: 12,335	I must admit that is above my pay grade. Have to wait and see,I guess. Then there is the question of LNBs and multiswitches, etc. What is the freq range of Ka band anyway? Last edited by rbinck; 03-30-2005 at 06:05 PM.

03-31-2005, 08:23 PM	#6
rbinck Administrator Join Date: Apr 2004 Location: Katy, Texas Posts: 12,335	What about the RG6, I wonder? RG6 goes up to about 1 Ghz. Last edited by rbinck; 03-31-2005 at 08:33 PM.

04-02-2005, 08:09 AM	#11
hdtv4me2 Go Bruins! Join Date: Aug 2004 Location: Maryland Posts: 1,284	Yes Channel; Yes or No? So what are we to expect from D* tomorrow regarding the Yes channel?

04-03-2005, 08:12 AM	#12
hdtv4me2 Go Bruins! Join Date: Aug 2004 Location: Maryland Posts: 1,284	Yankees/Red Sox Channel 95 I see that channel 95 is showing Yankees/Red Sox game at 8:30 PM EDT. Anyone know who is eligible to watch it?

03-31-2005, 12:15 AM	#3
calicogang High Definition is the definition of life. Join Date: Oct 2004 Posts: 473	That's by me also. I will e-mail a friend of mine about KA birds. Will post his answer as soon as I receive it.

03-31-2005, 08:24 AM	#4
hdtv4me2 Go Bruins! Join Date: Aug 2004 Location: Maryland Posts: 1,284	The Ka-band of frequencies is generally in the 20 to 30 Ghz range. Directv has already announced that a new dish would be required to receive the new Ka-band feed. The new dish is required since, as pointed out, the old dish's beamwidth would be narrower therefore harder to point and the new LNB would need to be able to operate in the higher frequency range.

03-31-2005, 06:24 PM	#5
jim6201 My plasma is High Def. Join Date: Jun 2004 Posts: 9	I believe the fact that Directv plans to change the satellite dishes solves my problem. The dishes will be smaller because of the higher frequency band used and, as was pointed out, new LNBs will also be needed because of the new frequency band. So it seems that we will be getting new HD receivers and new satellite dishes.

03-31-2005, 10:57 PM	#7
DTV TiVo Dealer ValueElectronics.com Join Date: Jun 2004 Location: Scarsdale, NY Posts: 200	The antenna dish LNB, (Low Noise Block) amplifies the signal and beats down the KU frequency to 900-2150 mHz so it can run on coax. BTW RG6 coax can support up to 2200 mHz with very little degradation. So the coax is only transporting the MPEG-2 data stream at 900 - 2150 mHz. DIRECTV will upgrade all HD customers with a new .66 meter dish with 5 LNBs, 3 KU receiving the current MPEG-2 101/110/119 satellites and 2 LNBs looking at the new KA MPEG-4 birds located at 99/103 degrees in the orbital slot. The 99 degree SPACEWAY 1 KU satellite is launching this week and the 103 degree KU SPACEWAY 2 satellite will go up later this year. -Robert

04-01-2005, 02:14 PM	#8
beatboy77 High Definition is the definition of life. Join Date: Jan 2005 Location: Colorado Springs, CO Posts: 59	Robert, So if I wanted to get ready for the Directv MPEG-4 Upgrade, should I run a 5th RG-6 cable from where my dish is mounted outside to where I will have the HMC? Thanks, Josh

04-01-2005, 08:09 PM	#9
rbinck Administrator Join Date: Apr 2004 Location: Katy, Texas Posts: 12,335	I was going by Belden's tables that stop at 1 Gig. Shows between 6-8db loss per 100'. That beating down the freq. explains it. Thanks.

04-03-2005, 10:19 AM	#13
beatboy77 High Definition is the definition of life. Join Date: Jan 2005 Location: Colorado Springs, CO Posts: 59	Go Sox!!!!!!!!!!!!!!!!!!!!

04-03-2005, 05:48 PM	#14
jim6201 My plasma is High Def. Join Date: Jun 2004 Posts: 9	Robert, I appear to missing something here. Why do you need 5 coax feeds? I have 4 coax feeds going to my main TV setup. Two coaxes feed my Standard Definition Tivo receiver, the third coax feeds my HD receiver, and the fourth coax feeds OTA signals to my HD receiver. My understanding is that unless I add another satellite receiver or upgrade my HD receiver to HD Tivo, I will not have to do any more coax installation for the Ka band system. I will have to swap my HD receiver for a new MPEG-4 capable receiver and install a new satellite dish. Do I have this straight? Thank you, Sir

04-03-2005, 07:56 PM	#15
Tony R 110" diag. - yea baby! Join Date: Apr 2005 Location: Atlanta Posts: 45	Is it a known fact that the existing oval antennas will be replaced with 66 cm antennas? Dropping the gain of the antenna for SD services is not a good idea. That means lowering the outage threshold during rainy weather. The beamwidth issue isn't so significant. The -3dB beamwidth formula is: signal beamwidth x efficiency of antenna reflector (%) / diameter (meters). The signal beamwidth is calculated by: 300/frequency (MHz). 300/30,000=.01 degrees. .01x60% (typical efficiency rating/.8. The difference is between .75 and .9 degrees. It seems to me that optimizing the feed to operate efficiently at both bands would be difficult since the focal point will be different for the two wave lengths. It would seem to make much more sense to have separate antennas for the DBS and Ka bands to prevent compromising performance between the two.