Channel Master dish and INVACOM LNB ?'s

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xtantaudio

Active SatelliteGuys Member
Original poster
Jun 11, 2008
16
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Indiana
Alright,

Only a few more questions and I can be up ad running enjoying FTA !!

I have a Channel Master 1.2M dish, I have removed all the extra bracketing and junk so that I can make the dish lighter, and I have begun creating my own mounting brackets for my HH motor....

Next item on the list: LNB compatability.... I have been getting some confusing stories from several different posts that I have read, so I figured I just better ask, and be sure to get the right parts the first time.

I have decided that I want to use the INVACOM LNB, but which one ???

Can I use a INVACOM QPH-031 LNB on the channel master 1.2M dish? the channel master dish has 3 aluminum arms coming out to the correct position to hold the LNB, and I believe the size of the holder is 40MM, so I should be good there... but somewhere I read that I need the INVACOM QPF-031 LNB, and I need to re-use my old feed horn from the old LNB so that I can adjust for skew... and I have also heard that the original feed horn is needed in order for the LNB to gather the signal correctly, so that I van get the best signal quality possible.....

Who is right and what is everyone's opinion? I will spend the extra money for the QPF-031 if I need that one in order to asjust the skew...

Thank you for everyones help.
 
Well, skew should be at '0' regardless of the LNB/feedhorn or LNBF that you're using, since it is taken care of by the movement of the motor. The Invacom QPH-031 LNBF will fit perfectly into the 40mm neck on that Channel Master dish, and it will work. It won't perform optimally for that dish, though, since you wouldn't be using the matched feedhorn that is made for that dish. You'd gain a few quality points by mating the QPF-031 onto the original feedhorn (minus the waveguide, if it had one), but the QPF-031 is very expensive (about twice the cost of the QPH-031). Is it worth that money for the few extra quality points? Not sure about that one :)
 
I do not think that any motor will move that dish reliably, especially with the QPH-031. 1.2m dishes are heavy and that one is a little heavier then most.
 
Tron summed it up well. When I did my last Channel Master/Invacom project the lowest priced QPF I could find cost 33% more than the lowest priced QPH, but that took a lot of shopping around and a little luck too.

I suggest laying out the extra cash for the QPF. You will have the peace of mind of knowing that the feedhorn is seeing every square millimeter of that magnificent 1.2 meter reflector.

Here are a few shots of my .9 meter Channel Master / Invacom QPF-031 project:
 

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I have found the INVACOM QPF-031 for 89.99 online, not a bad price i guess. I suppose that it is worth a little more so that I can successfully get the most out of my dish setup...

I had been looking all over the forums for pictures of someone with the same dish and that QPF LNB so that I could get an idea what I was going to be up against.

Thank you everyone, and as always, if you have any more input or suggestions, please post !!!

by the way GrumpyGuy, what size motor are you using on your setup - part numbers if you could...
 
looks like the stock SG2100

the back bracket was fabricated to get as much weight off the dish as possible
 
Iceberg, you are everywhere on these forums !!! and you always have the answers. Thank you very much.

I have started the fabrication of my new bracket for the back of the dish using some information that was referenced by another member of the forums.... so far so good.

Thank you everyone for your input... I will order the LNB later this week and let everyone know how its going. I will post pics and info...
 
Ice is correct (as usual), the motor is a stock SG2100.

One thing I will do differently next time around - modify my mount design to place the dish higher in relation to the motor, placing the dish's center of gravity closer to the bend in the motor output shaft. The way things are now, the motor has to do much more lifting of the dish than necessary, particularly at the far ends of the arc.

This will be even more important for your setup, xtanaudio. As vfrjim points out, you plan on moving a heck of a lot of fiberglass. Your 1.2 meter dish has roughly 2X the area of my .9 meter, probably roughly 2X the weight too.
 
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