Adjustable feedhorn scaler rings

npire1

npire1

Regular Member
My Satellite Setup
Humax Foxsat with 2.5m prime focus dish & Invacom quad lnb
My Location
Prietrzka Slovakia
Ive got a C120 Invacom quad Lnb with adjustable feedhorn on my 2.5m prime focus dish and I was thinking to double check the f/d ratio but does anyone know how to adjust the scaler rings to match the f/d ratio when there are no markings on the feedhorn ? i.e lets say f/d ratio of 0.32 = zero cm's (feedhorn would be flush with scaller rings)
 
If you want the best from your 2.5m dish you're best off throwing that in the dustbin. I've tried a lot of feeds on PF dishes and it is one of the worst performing feeds I cam across especially in bands C & D.
 
Yes, the feed horn.
 
Huevos said:
Yes, the feed horn.
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Im using it now here In Slovakia but I only get a few hours of 2e each morning if im lucky ! 2f Is better most days but still only till afternoon in a good day ! Do you have any names of another i could try before i give up completely and go to internet streaming ? also that wont break the bank ?
 
Before you go to internet streaming try one more thing: Get GI-209P LNB, which is designed for PFA. I have very positive experience with that.
 
RimaNTSS said:
Before you go to internet streaming try one more thing: Get GI-209P LNB, which is designed for PFA. I have very positive experience with that.
Click to expand...
Ok I will check It out, thanks
 
Late model Famaval is the absolute best SNR reading feed I have tried. Not sure why the adjustable ones I tried performed so poorly, but I did notice the bore was much smaller. The other problem is the thread is very fine and sometimes they jam. And once they jam they are knackered.

Here is a graph of how to set the adjustable feed.
feed-adjustment.webp
 
Ok thanks ! So the edge of the mouth of the feedhorn to the centre of the dish is the focal distance and the f/d ratio is the scaler rings distance back from the mouth of the feedhorn by whatever the chart says , say 0-7 cm's right ?
 
Its funny thats a much cheaper lnb compared to my Invacom !
 
mm, not cm. It is how much thread is poking through. The best thing though is to forget all that and just adjust it for maximum signal quality. Too much theory and not enough practice. ;)
 
Huevos said:
I've got the Invacom on my dish and it is a great LNB.
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Yes I bought it because everyone said it was the best but do you think its not the best for such a large dish ! Is that what your saying ?
 
shame i cant just try a differnt feedhorn as the invacom is a quad and my dvr uses two cables !
 
Yes you can. Just change the feedhorn. Don't change the LNB.
 
Huevos said:
Yes you can. Just change the feedhorn. Don't change the LNB.
Click to expand...
Oh but so does the "GI-209P LNB" feedhorn come off and fit my c120 flange ? or do they just sell the feedhorn part ?
 
or are we saying a famaval feed horn is better ! Im confused !!
 
Huevos said:
Late model Famaval is the absolute best SNR reading feed I have tried. Not sure why the adjustable ones I tried performed so poorly, but I did notice the bore was much smaller. The other problem is the thread is very fine and sometimes they jam. And once they jam they are knackered.

Here is a graph of how to set the adjustable feed.
View attachment 61888
Click to expand...

Hi, can you point me to a supplier of these feedhorns, i have googled, but no joy. Thanks
 
npire1 said:
or are we saying a famaval feed horn is better ! Im confused !!
Click to expand...
Yes, and I didn't mention the other LNB, which I am not familiar with.
DishDick said:
Hi, can you point me to a supplier of these feedhorns, i have googled, but no joy. Thanks
Click to expand...
Digital Satellite Systems, Finestrat, are a major agent in Spain.
 
Thanks Huevos. Also is there an easy way to distinguish between a Marrafa and a Famaval dish?
 
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