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focal point setting
Posted: Thu Sep 05, 2019 12:33 am
by sean2e0saf
anyone give any pointers on focal point setting prime focus IRTI 1.5m dish i measured the original FP to be about 625mm from the tip of the scalar rings on the original feed horn.. i assume i simply use these same measurements for new lnb and patch antenna waveguide then i put the cap on..?
thanks all
Re: focal point setting
Posted: Thu Sep 05, 2019 4:05 am
by RimaNTSS
It is always possible to calculate. You just need to precisely measure diameter and depths of the dish and then enter data in some of the calculators, like this
https://www.satellite-calculations.com/ ... lector.htm
Make sure feed is pointed to the center of the dish. Also move feed closer/further and observe when signal lever gets maximum.
Re: focal point setting
Posted: Thu Sep 05, 2019 6:53 am
by radiogareth
As above, measure and calculate. I was able to 'prove' by using the sun and putting a small piece of paper to 'see' the focused sun - but my dish is clean alloy - no paint. You can also use your hand......with care if its a big dish - mine is 66 cms and it gets hot!
Gareth