Better Ku performance on BUDs

[Anole]

.
Reports vary widely on performance of dual band lnbfs.
C band will be compromised a little, compared to C-only lnbfs, but maybe not that badly.
Reports of Ku performance is all over the place:
.
- At one time, I thought it might have to do with dish size, which nobody reports.
.
- I'm pretty sure dish accuracy at Ku is a big factor, with spun aluminum and molded solids (ChannelMaster) taking the lead over sloppy mesh.
.
- A proven component is critical alignment accuracy, which will vary from member to member.
That is compounded by the fact that C/Ku lnbfs really don't see the entire dish (only just the center, if you are lucky).
.
So, if anyone is interested in experimenting, I propose the following test:
.
Compare a dual band lnbf against a side-mounted Ku lnbf with a proper scaler that sees the entire disk.
Put the Ku scalar beside the C band scalar, or inside it.
?You decide which to put on bore sight, or to offset each a little bit.
.
SatelliteAV sells a suitable Ku lnbf, or put the lnb of your choice on an Invacom AF-120 Ku feedhorn.
?Yes, That means moving the dish to get both bands from a single bird.
.
But if this should prove better than dual band lnbfs, it's well worth the effort.
?.

.

 

[turbosat]

Tired ku with the 10' SAMI before, using the old co-rotor lnb, but haven't experimented any more since the S2 signals became more in use. I was surprised-the big dish with its ku-small hole mesh seemed to do as well as my ku only primestar dishes. But since I have half a dozen of those little dishes, I decided to just stick with the multi=dish system. Figured I would wear out my actuator much faster if I used the one dish for everything, haha. I should try again with a real ku-c lnbf though soon just for grins.

 

[radio]

Originally after going "all FTA" I used only a combination c/ku on my solid Birdview. (supplied by Iceberg, as a matter of fact!) It is still in use, and seems quite adequate in performance and very good in signal catch if there are no unusual skews, or odd signal "issues." It performs nicely, and I cannot remember why, but I'm not using the built-in switching on the LNB for that, but rather an external diseqc. I will admit, however, I've had much more stable results on some signals with either a channel master .75 meter dish dedicated, or....a 1.2 ku also dedicated. So, for odd signals like Cozi, or ones near the far end of travel (125 or 72) I've used a switching system on dedicated dishes.

It would be EXCELLENT to find a way to make c and ku equally efficiently on the birdview. Creating a mount for it would prove quite interesting. Wish I hadn't dedicated my spare BV to 137C-Band...I'd play with it and report on this thread!

 

[mmewrench]

I have had ku on my bud for years (only used a combo lnbf for a short time) and I can tell you that dish alignment and positioner accuracy are 98% of the problems that people are having. I used the combo lnbf to set up my dish in the first place. I peaked it using ku transponders since they require a more accurate alignment. The next step was to replace the actuator (higher pulse count) and peak it some more.

I can switch between both dishes easily to compare signal quality, and I can honestly tell you, My ten foot bud gave me the same quality numbers as my ku dish until the rain started or the snow was falling (I still have quality on the bud, but the ku dish has none).

 

[Vallenato]

on question on this If I have C band already with strong signal and I am looking ku band in the same satellite (example satellite intelsat 21) To lock the KU signal (after switch my LNB) What I need to do? Move the elevation little bit Up? down? or the azimuth little bit east? or west? of the dish antenna. Using solid WSI 8'

 

[FaT Air]

If it's not your Zenith satellite, don't mess with the elevation. That is ONLY adjusted at Zenith. (Zenith being your most southerly satellite)
Away from Zenith, use only the actuator and readjust the Azimuth to maximize "Q". The actuator does the elevation on the ends of the arc, you adjust Azimuth.

 

[Vallenato]

If it's not your Zenith satellite, don't mess with the elevation. That is ONLY adjusted at Zenith. (Zenith being your most southerly satellite)
Away from Zenith, use only the actuator and readjust the Azimuth to maximize "Q". The actuator does the elevation on the ends of the arc, you adjust Azimuth.

Sorry I forgot to mention.. My Dish (right now) is not motorized dedicated Only to intelsat 21 C band
pd: i have everything to motorize maybe in the nexts weeks after read & read

 

[RimaNTSS]

I've tried combined C/Ku LNB on 1,5m polar-mounted PFA. TBH, very disappointed with performance in Ku band. Measurements did on Dreambox 8000. All data put in table, where last two columns - minimum and maximum of single Ku-band LNB (in my case GI-209P), and 2 columns before them - minimums and maximums of combined C/Ku LNB.
My conclusion: should use separate dish for C-band, and another dish for Ku-band reception.

 

[Magic Static]

I have very good KU performance on my 3M BUD. But it took a lot of money and effort to do so.

 

[toucan-man]

I have very good KU performance on my 3M BUD. But it took a lot of money and effort to do so.

Sure looks pretty. Would look even better at my place.

 

[Magic Static]

Sure looks pretty. Would look even better at my place.

It would definitely get more channels at your place

 

[Anole]

I've tried combined C/Ku LNB on 1,5m polar-mounted PFA. TBH, very disappointed with performance in Ku band....
My conclusion: should use separate dish for C-band, and another dish for Ku-band reception.

Here in North America, a 1.5 meter prime focus would be too small for serious FTA on C band.
But I think my suggestion WOULD get you much better Ku!.
At least here, a 1.5m Ku dish would be superb.
Signal levels in your country may be much different.
?.

 

[RimaNTSS]

At least here, a 1.5m Ku dish would be superb.
Signal levels in your country may be much different.?.

Ku-band signal levels nowadays everywhere are strong enough to get almost all of them on 90cm dish. And that is also enough to have some reserve in case of rain. However there are signals in the air could be received by only using bigger dish, and this is more for hobby (my case).
Mesh dishes you guys are using good only for C-band, but in Ku-band they perform not for their size (that what I've heard about mesh).

 

[stecle]

.
Reports vary widely on performance of dual band lnbfs.
C band will be compromised a little, compared to C-only lnbfs, but maybe not that badly.
Reports of Ku performance is all over the place:
.
- At one time, I thought it might have to do with dish size, which nobody reports.
.
- I'm pretty sure dish accuracy at Ku is a big factor, with spun aluminum and molded solids (ChannelMaster) taking the lead over sloppy mesh.
.
- A proven component is critical alignment accuracy, which will vary from member to member.
That is compounded by the fact that C/Ku lnbfs really don't see the entire dish (only just the center, if you are lucky).
.
So, if anyone is interested in experimenting, I propose the following test:
.
Compare a dual band lnbf against a side-mounted Ku lnbf with a proper scaler that sees the entire disk.
Put the Ku scalar beside the C band scalar, or inside it.
?You decide which to put on bore sight, or to offset each a little bit.
.
SatelliteAV sells a suitable Ku lnbf, or put the lnb of your choice on an Invacom AF-120 Ku feedhorn.
?Yes, That means moving the dish to get both bands from a single bird.
.
But if this should prove better than dual band lnbfs, it's well worth the effort.
?.

.

Anole your post here peaked my interest, especially your statement "That is compounded by the fact that C/Ku lnbfs really don't see the entire dish (only just the center, if you are lucky)." I am curious what you mean by this?

I remember back in the day there was a 10 foot brown mesh dish made by Wagner. To make the dish Ku ready, they added a solid aluminum panel over the mesh which had about a 6 foot diameter. In other words, the solid aluminum panel did not cover the entire 10 foot surface of this dish, just the center. I always wondered why it was built in this fashion, not covering the entire surface.

I did a comparison myself between a 36 inch solid offset and a 10 foot mesh. My 10 foot slightly outperforms my 36 inch solid on KU. I am using a California Amp C/Ku feedhorn which outperforms the Co-rotor in my opinion.

The Sg 2100 motor that I was using on the 36 inch dish will not work in the winter where I live so that is not an option for me anyway.

Steve

 

[Anole]

The scalar & feedhorn get illuminated by the whole dish.
Well, on C band that's true.
The Ku feed is just a pipe looking at the dish.
And it's often buried inside the C plumbing.
It really just sees the center of the dish.
(So, getting it centered is even more critical)
.
The big scalar is frequency sensitive, so it doesn't do squat on Ku.
So now you're without any scalar on Ku.
No wonder Ku sucks.
?.

 

[GI_Joe]

The scalar & feedhorn get illuminated by the whole dish.
Well, on C band that's true.
The Ku feed is just a pipe looking at the dish.
And it's often buried inside the C plumbing.
It really just sees the center of the dish.
(So, getting it centered is even more critical)
.
The big scalar is frequency sensitive, so it doesn't do squat on Ku.
So now you're without any scalar on Ku.
No wonder Ku sucks.
?.

This also peaked my interest. I have spent countless hours fine tuning a C/ Ku dish just trying to peak the signal on Ku. It wasn't until I started playing with the "centering" of the LNBF around the C band scalar ring that things started to make sense.. You can reach a middle ground where things are "usable" but I have found that there's nothing better than a dedicated offset dish for Ku - esp if it's something weak.

 

[Lone Gunman]

Ok so I've been in contact with Anole via PM about this mod and I went looking for one of these. SL1P - GEOSATpro SINGLE STANDARD KU PRIME FOCUS.

The ones I found were priced right but damn, the shipping is half again what the LNBF itself costs?? :rant:

Anyone know of a dealer that sells these with some kind of reasonable shipping charges, ie, less than $14.99?? I was thinking about $8 should do it. Since this is just a test, I hate to spend a whole lot of money doing it especially since I just bought a new receiver last week. If this doesn't work then I'm going to be stuck with it so I don't want to spend much for one.

Thanks

 

[Magic Static]

Nevermind

 

[tekjunkie02]

Couple of thoughts/comments

Shouldn't a parabolic dish focus all the signals to a "prime focus point"?
Wouldn't the Ku signals be focused to that point? and if the opening of the feed horn is that point, wouldn't the Ku signals then continue traveling within the feed, til they eventually hit the antenna?
If the focal distance is different depending on the wavelength of the signal, then that, I guess, would explain why one band works better than the other.
Otherwise, I'd guess it would have to be a problem with the accuracy of the parabola, or the positioning of the feed. Or, maybe the signals themselves are arriving at the dish surface slightly offset from each other (C and Ku) requiring the dish to be focused as a "compromise" instead of precisely focused to one signal or the other???

just some thoughts to feed more thoughts and discussion... I find it very interesting trying to understand and learn how this all works!!

Thanks,