Stack Two KU Dishes?

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Indy

SatelliteGuys Pro
Original poster
May 13, 2004
992
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Indiana
I have never tried this and searched the forums with no results. Is it possible to aim two smaller 30" KU sat dishes at one sat location and combine the LNB signals for a stronger signal? Just like the SETI setup where all the smaller dishes act as one BIG dish.
 

Fat Air, Interesting technical evaluation of the concept within  your response to a previous thread. I never gave any thought to the nuances of signal phase and/or timing of the two signals. My simple idea was, increase the size of  the net and catch more of the signal. I was thinking the STB could put the whole image back together again drawing on the cach of image bits from the two signals. I may try this tomorrow with a passive splitter and identical LNBF’s just to look at insertion loss or gain.
 
I may try this tomorrow with a passive splitter and identical LNBF’s just to look at insertion loss or gain.
Short answer: It won't work.

Each LNBF has its own local oscillator, and they won't be on the same frequency, much less in phase with each other.

edit:
I once saw some fancy C-band LNBs.
They took DC power AND a 10mhz master signal up the coax.
The LNB phase locked itself to the 10mhz reference, to make the actual LO frequency.
Then, the LNB piped the output signal back down the coax in the 950-1450 mhz range.

A clever fellow might be able to get those to work.
Plus, the lower frequency of C-band would be less critical, too.
BUT, you'd probably still need equal length coax from both LNBs to a proper combiner, as well.
 
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And those adjustable delay lines would have to be "continuously variable" to the uuS (micro-micro second)
The SETI project, that uses(d)multiple dishes. cost BILLIONS. There is no solution that is feasible to the recreational satellite user. [I added the (d) as it's been shut down because of funding issues]
My simple idea was, increase the size of the net and catch more of the signal
The ONLY cost effective way, for the casual user, is a bigger dish. ((I love my CM 1.2's))
 
One of our Gold Sponsors have/had (?) 1.2m dishes on sale.
Whatever they cost to buy, and whatever they cost to ship, is the 2nd cheapest solution to the problem.
 
One of our Gold Sponsors have/had (?) 1.2m dishes on sale.
Whatever they cost to buy, and whatever they cost to ship, is the 2nd cheapest solution to the problem.

I did check, he is sold out of the 4' offset. I have a 36" I purchased with the STAB motor a few years ago from Sadoun but would like to get something a little bigger. I have seen new 6' prime focus dishes on ebay from a seller for a pretty good deal shipped. That would work as a stationary dish for my primary interest which is AMC3. I think the 4' would also work, I only need a couple of points on the signal quality to lock on the transponder I want.
 
If something like this was to work with satellite for cheap then it would be able to be used in other applications as well. It would be even more useful such as wireless internet although the transmissions going back may be a problem as well (would probably have to have two more dishes/antennas perfectly in sync to transmit back) or preferably a different way to transmit that signal back such as cell phone signal since it does not take as much data to request the packets. It would be revolutionary if it could be done on the cheap. Will probably never happen though. The noise ratio would probably be higher than the signal in most cases.
 
actual solutions

The third cheapest solution is a 6' prime-feed dish.
That'll get your Ku signal, for sure! - :up

Robby at WSI (Galaxy Marketing, top of any page, here) was offering it to us last month.
You might call him up and see if he has one left, and ask about shipping.
Since it is broken down into six pie-shaped wedges, it's small and relatively inexpensive to transport.

The dish is kinda light weight, so I'd recommend keeping it close to the ground, and shielded from high winds.
If you do that and use it for fixed operation , it should be a sweet-heart deal.
You will need a proper Ku LNBF to match the prime feed reflector, though.
No cheating here with a regular Ku LNBF.
And forget about using a dual band C+Ku, as it'll suck for Ku!

SatelliteAV had some prime-feed Ku's for pretty cheap, but I believe he closed them out.
You might ask on the forum if anyone has one left.
Someone bought his remaining stock
I only got one, and am keeping mine. ;)

Or, WSI/Galaxy may have a similar unit, I haven't looked to see.
Both SatAV and Galaxy are our Gold Sponsors, and you'll find links to their sites at the top of every page.

Lastly, try one of the DMSI dealers (maybe IvyStonePlace.com) and look for model BSC321SP.
They drop-ship direct to you from DMSI.

I seem to remember a prime-feed horn from Invacom.
Think it was called an AF-120.
Sadoun.com used to offer them, and I recently saw 'em on their site.
Mating that to a flange-mount Invacom LNB would be expensive.
Alternately, you might use a DishNet FSS LNB with the Invacom feedhorn, though they're bandstacked.
Or, Hughes, Primestar, and Eagle-Aspen would bolt right onto the AF120, too.
They look like a soup can. :cool:
 
Anole, The 1.8 meter Prime Focus looks like the one I want and is the same model on ebay. .I will give Robby a call in the morning. I have several Eagle Aspen LNB's on Primestar Dishes from past projects so I wouild only need the ring and feedhorn. Or I could go with what Robby may suggest for a static install for AMC-3.Thanks for the info!
 
best deal:

The prime-focus-friendly Ku LNBF from SatAV/DMSI would be considerably cheaper than an AF-120 feedhorn (about half).
Again, if Galaxy has a similar unit fine, but NO C+Ku combo LNBFs!
Not on a 6' dish! Not when you are begging for your Ku signal.


And now as to the #1 most cost effective solution:
The ONLY cost effective way, for the casual user, is a bigger dish. ((I love my CM 1.2's))
He's saying he got a (free) Channel Master / Andrew / Primestar 1.2m dish and no doubt, original feed 'n LNB!
See picture below, and salivate! - :up
 

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I ordered the 1.8 meter Prime Focus, star bracket and KU LNB from WS International. Galaxy Marketing
 
Fat Air - I may have to hunt you down! :up

Indy - what part number on that KU LNB? I'm not feeling good about this.
 
Fat Air - I may have to hunt you down! :up

Indy - what part number on that KU LNB? I'm not feeling good about this.


Hmmm.... Good question. I told the man on the phone, not Robby, what I was trying to accomplish and left it up to his discretion on what was needed. He sold me a dish, star bracket and KU LNB. No C band on the LNB. The items are in shipment and I never received an invoice. With that in mind I guess I wait until everything arrives and I can always change things latter if you guys look at things and see a better way of doing this. Not much capital has been invested at this point, so no real problem
 
Okay, Robby may have a prime-feed Ku LNBF, similar to the inexpensive DMSI unit.
I just didn't see it on his site. (and I hate visiting since he put in that spinning globe in the lower left corner; it sucks my CPU dry!)

I just wanted to make sure you had all the relevant parts at the same time.
No point waiting 'till the dish comes in, then discover you need to wait another 10 days for someone else to supply an LNBF.
But, seems you've got it all under control. :up
 
Hopefully under control or at worse, a calamity of miss matched parts for the piles of un used parts in my basement!I agree on the Galaxy site, real bandwidth hog with a new a window opening for each item. And to top it all off, no continuity within categories, order of like items, or search option. Plus, you cannot even place a web order for some items, like the dish. Robby, if you read this post, do yourself a favor and invest in a website designer who knows what he is doing. 80% of your business is depending on a smooth internet shopping experience which is sorely lacking with the present setup. Just my 2 cents worth.
 
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