F/D Focal point on prime focus dish

D

dave branson

Regular Member
Messages
316
Likes
0
My Location
Florence Italy
#1
I have a 1.8 irte prime focus dish,when i calculate the focal point using
using the programme of satellites-comunications.com,it gives a focal length of 67.5 cms.
On checking the my dish the focal length is some 75 cms.
At the moment I get BBC/ITV during the day,goes off about 19-00 hrs,
in the winter it lasts a lot longer,but thats another dicussion.
I am using a Invacom quad and adjustable feed horn,which is at maximum on the lnb bracket,( set to 0,41 f/d ) leaving the focal length
at 75 cms.
so my question is ,is the focal length very important, if so,where can i get a longer feedhorn.
 
N

Neophasis

ASBO Club Member, AKA Likvid
Messages
30
Likes
0
My Satellite Setup
None
My Location
EU
#2
Use the SMW Depolarizer/Waveguide

http://www.smw.se/res/pdf/feedhorn.pdf

Remove the plastic teflon part inside the waveguide and it will work great for you.

Connect the feedhorn to one side and the LNB to the other side, that way you get a longer feed.
 
Llew

Llew

cerca trova...
Staff member
Messages
14,538
Likes
3,436
My Satellite Setup
Triple Dragon, Dreambox 8000, Echostar AD3000ip, TBS6522,6925,6983 PCie cards.
Gibertini 1.25m motorised dish driven by the AD3000, with either Inverto BU Quad or Norsat / XMW Ka LNBs . SMW 1.05m + 3 other dishes. Speccy: Promax HD Ranger+
My Location
The Flatlands of East Anglia
#3
You'll need the C120/120 adaptor to match waveguide to Invacom LNB.

Llew
 
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