Anybody try a Multi-dish array

[mbarnes]

Has anyone tried using a multi dish array of small dishes instead of one large dish? I know they do it for space communications and radio astronomy. Instead of having one humongous dish, they use an array of smaller dishes all pointed at the same place. That way, they use three or four 40m dishes to get the equivalent of a single 350m dish.

It would be interesting to take three old DBS 18" dishes, mount them about three feet apart and tie them together instead of finding a three or four foot dish.

Thoughts or comments?

 

[phlatwound]

I know the idea has been shot down here more than once, if I remember correctly it was due to the multiple signals most likely being out-of-phase.

 

[pendragon]

Actually after pooh-poohing this a few times, I came up with a possible way of implementing it and published an outline the last time one of these threads went by. I don't have a link handy, though. The downside is you would have to use LNBs that can be phase-locked to an external frequency reference, and these are very expensive. It might make sense to combine several 10-12' dishes, but not 18" dishes.

Be aware that the collection surface area goes as the square of the linear dimension; you would need at least eight 18" dishes to equal the gain of a 4' dish even with minimal aperture combining loss. Also be aware that one of the reasons this is done in radio astronomy is to increase the angular resolving power through a long baseline, as opposed to simply increasing the system gain.

 

[greg harris]

http://www.satelliteguys.us/free-air-fta-discussion/16269-anobody-tried-dish-array.html

 

[pendragon]

Found it:

http://www.satelliteguys.us/free-ai...l-two-18-dishs-more-signal-2.html#post1911483

See also the follow-up posts.

 

[Dee_Ann]

Zane Zaminsky knows how.



[ame="http://www.youtube.com/watch?v=KfhARMG6ATU"]YouTube- The Arrival - 5. "Satellite Array"[/ame]

 

[Tron]

Nice clip Dee... I just got that movie on Blu-Ray (it was dirt cheap at Wally World), but I've never seen it. I want to go pop it into the player right now just for the satellite dish content ... There must have still been enough people with active BUDs back in 1996 for that sequence to be plausible.

 

[Dee_Ann]

Oh that's stupid. Yesterday it let me embed the clip and today it says it's disabled. :rant: :rant:


I'm not much into the sci-fi genre but this is one exception. I thought this was a really well done movie. And it's like super freaky bizzaro too. I think this is one of the better ones.

Oh, I also liked Contact a lot and there was a weird TV series in the 90's about some couple that was chasing down aliens that got into people's heads. (They should have checked GWB #43 & Cheney, I'm sure they are both infected with aliens )

 

[tamuin]

Cheap PLL LNB

... the downside is you would have to use LNBs that can be phase-locked to an external frequency reference, and these are very expensive.

I thought I had read that there were now inexpensive PLL LNB that had been developed for the VSAT market. I could not find anything quickly using google, but I thought that I would mention it, maybe someone else has more info.

 

[pendragon]

Most PLL LNBs are locked to an internal oscillator. For this application you need the type that locks to an external reference. A rarer breed.