120cm fibre dish, anyone knows this brand?

pedro2000uk · 03-02-2009

Originally Posted by pipino

those LNBs have WR75 connection and not C120 you would need a polariser (mecanic better) in the same time it will do a convertion from WR75 to C120 (feedhorn or depolarizer)

Is that lnb DRO or DLL...?

**pipino** · 03-02-2009

i would say a DRO ,as i remember we could tweak the oscillation frequency by the turning the big Trimmer inside,we cant do that with PLL lnbs

pedro2000uk · 05-02-2009

Originally Posted by pipino

i would say a DRO ,as i remember we could tweak the oscillation frequency by the turning the big Trimmer inside,we cant do that with PLL lnbs

On the outside of most LNBs (f's or C120's) in the plastic cover or visible on all metal cased ones... there are what look like 3 production final fine tune screws -usually 2 together & 1 on its own.. do you know what is for what....

**pipino** · 05-02-2009

thats to tweak the oscillator,usualy is done in the labs before they get into the market

pedro2000uk · 05-02-2009

Thanks Pipino...

Do you know what the 2 are for and what the one is for exactly .. and what can you tweak... it's performance over the whole of KU ... move a peak point up or down KU (hmmm) ..... lift a frequency and loose it elsewhere.. .... blow it up/melt it... or the stb!

I know fine tuning waveguides can come down to drilling a hole, bunging a screw in the waveguide and screwing it in and out to see if it helps bounce the flow .. very exacting science ... as is so much of radio electronics... a mix of complex, accurate formulas and inspired (or blind) guesswork...

Wouldn't be the same if it wasn’t.

pedro2000uk · 05-02-2009

OK ... the two screws are for 9750 & 10600 local oscillator blocks.... to fine tune each by simply bringing pressure on them to fine tune their frequency by how solid or loose they are held...

(Think I did all this 10 years ago... hmmm.

.. used to be only one then.....)

can't remember if it didn't 'shift' the L.O. frequency 'offset'... so it could mess the frequencies up without modifying the LO settings as well ....... depends on the range as to it's usefulness.

**pipino** · 05-02-2009

all correct ,i also use to play with the old MASPROSs and SPCs to get hight and lower bands ,can be modified to work as a transmiter too,,god we are talking more than 20 years ago

pedro2000uk · 05-02-2009

I think it is c. 20 years.. just remembered what I was doing 10 years ago..

note to self... must cut down coffee ............ (that'll happen).

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120cm fibre dish, anyone knows this brand? Information exchange on LNBs, Single satellite, motorised and multi-satellite systems. DiSEqC switches, positioners, motors, actuators, dish-alignment etc.