i can't believe the signal quality with this 1.2 and k band lnb.

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chaskuchar

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Apr 16, 2010
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saint charles, missouri
i am used to using the dmx741 on my 6' and 8'. now this 1.2 is much more signal quality than the bigger dish. suppose i change to two lnb's, c and k, and use the 22k switch at the dish and improve my reception? or is the dmx741 good on the c band and just add a better k band lnb? thanks, charlie
 
Think your best performance will be with a single C band LNBF on your 6 and 8 ft prime focus dishes, and a Ku LNBF on the 1.2 offset dish. Think I read somewhere that a Dual band LNBF and a 6 ft dish gives the performance of a 80cm offset dish at best.
Think you can use the 741 peaked for C band on the prime focus without much loss of signal. Use an outboard 22 Khz switch to go to a Ku lnbf on the 1.2 and have"the best of both worlds". Think the 'dual band' LNBF's compromise 'too much' to do 'too much'. I love my 1.2's. Went the outboard 22khz sw route a while ago, and am NOT looking back.
 
The rule of thumb (mine may be bigger than yours) ;) is that a 1meter Ku dish out-performs a "regular" BUD with most of those two-band LNBFs.

Better C takes a better C-only LNBF, or a C-only ortho feed (best).
Better Ku takes some magic.
Pendragon has explored some of the limits.
A dual band ortho can do well on Ku, and nearly as good on C as a C-only ortho.
Is your head spinning, yet?

A really high accuracy BUD is probably a necessary component of good Ku.
And "most" BUDs don't qualify. :)

As you've discovered, a 1.2m dish is a really good solution!
 
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Charley, The 741 works good on a larger dish if you want to get reasonable signals on both bands. I am using a (repaired) C2 LNBF on my 10' dish now because I get an improvment on C-band over the 741 I was using. Not much of a difference, maybe 2-4%Q average across the board, maybe a dB or so better s/n. I use a 36" Ku dish on a seperate motor and find it much more consistant (maybe the signals are a bit less but sufficient). Your 1.2m should give really good signals on Ku with a Ku standard or universal LNBF.

Ku was always a real pain to line up on the big dish... any breeze or if the satellite landed between two "clicks" on the positioner, I would get a poor signal. I suspect the issue is the apature of such a large antenna is so narrow on Ku frequencies that it's difficult to get the aim good enough to maximize the signal. If I got it peaked on one satellite, moved to another, then back again the alignment was off again. Likely a little play in the polar mount and/or positioner messes it up. It would work but not great.

The 741 is a good LNBF though and works well on C and Ku. I find it's performance about the same as a corotor II with good DRO LNBFs (my sig), and a whole lot cheaper. Note that I am referring to the standard 741, not the universal Ku model. To get functional improvment you would likey have to spend some real money!
 
Satellite AV was the first North American distributor to import a C/KU LNBF, the GEOSATpro CK1. At the time that we introduced the product, we advertised that it was not an optimal solution, but provided a solution for users who wanted voltage controlled polarity with C and KU band coverage. After distributing the CK1 for several years, the chipset was discontinued and we had to make a decision to move to the solution that our competitors were distributing or discontinue the product. We chose to discontinue rather than sell a product that had even lower performance.

The best solution continues to be a feedhorn with polarization controller and separate C and KU LNBs. If you want the convenience of an voltage control polarity (LNBF), chose a C-band only unit.

Read the reviews. Not all are created equal!
 
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