indian lnb hack jobs for dual band

D

drspastic

New Member
My Satellite Setup
2x 2.4m prime, 1.15m prime, 80cm offset, c, ku, x, s, l bands.
diy jacks, rtlsdr, gtmadia finder 2 and a couple old dreamboxes. soon to get pluto+ and 160w uplink amp.
os used is linux or android
My Location
ex pat living in bulgaria. my south is badr/eshail 2
i keep seeing videos where indians are cutting the back from a c band lnb then mounting a ku band behind it.
at first i thought they were idiots, but thinking more about it, the physical lnb is just a closed tube to keep the antennas clean and dry, snf ku band signals shouldnt resonate the c band antennas therefore power might not be lost.
i assume once the signal is in the wave guide its getting funneled until it hits something.
now i have seen some c/ku band lnb on the market but no doubt they also lose signal either from switching circuits or just being a compromise.

anybody got thoughts on this? anybody tear down a combo lnb to see the guts?
 
got any links....
 

theres lots more. all sawing off the end and gluing the ku on
 
drspastic said:
i keep seeing videos where indians are cutting the back from a c band lnb then mounting a ku band behind it.
at first i thought they were idiots, but thinking more about it, the physical lnb is just a closed tube to keep the antennas clean and dry, snf ku band signals shouldnt resonate the c band antennas therefore power might not be lost.
i assume once the signal is in the wave guide its getting funneled until it hits something.
now i have seen some c/ku band lnb on the market but no doubt they also lose signal either from switching circuits or just being a compromise.

anybody got thoughts on this? anybody tear down a combo lnb to see the guts?
Click to expand...
Hi

Your assumption that the combine units are a compromise is correct - in my view.

I bought one from America many years ago .... and i,v also constructed one from separate l.n.b,s (see pic below) ... C band was good on both of them ....... the home made one gave marginally better k/u results than the purchased one - as it had coned scalar rings on the k/u part - so was better suited to the 1.8 Channel Master offset dish that i was using.

home made c ku.webp

Some more of my findings - and views - on these combo units in post 40 of this recent thread ....

Just Sharing This - Modified my CM LNB holder for KU and CBAND

wouldn't the ku band balance be disturbed then? :confused Yes, but you drop the dish down by 5 to 6 degrees again then Ku comes back in focus. Best to use another jack for the elevation ideally..
www.satellites.co.uk www.satellites.co.uk

Cheers.
 
nelson_b said:
Hi

Your assumption that the combine units are a compromise is correct - in my view.

I bought one from America many years ago .... and i,v also constructed one from separate l.n.b,s (see pic below) ... C band was good on both of them ....... the home made one gave marginally better k/u results than the purchased one - as it had coned scalar rings on the k/u part - so was better suited to the 1.8 Channel Master offset dish that i was using.

View attachment 143976

Some more of my findings - and views - on these combo units in post 40 of this recent thread ....

Just Sharing This - Modified my CM LNB holder for KU and CBAND

wouldn't the ku band balance be disturbed then? :confused Yes, but you drop the dish down by 5 to 6 degrees again then Ku comes back in focus. Best to use another jack for the elevation ideally..
www.satellites.co.uk www.satellites.co.uk

Cheers.
Click to expand...
thanks for that. i guess i will give that a miss then.the scalar rings for my ku lnb are the same diameter as the c lnb and it can fit inside the c scalars with the c lnb removed. will there be loss/gain/no change by having both sets? ignoring the small shadow loss.
i dont have great test gear to check yet
 
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