QO-100 OCTAGON Ext. Ref. Modification

I tested and modified several different LNB`s.
This Octagon Green is one of the best LNB for Ham Radio QO-100 use.
I added a 25MHz GPSDO Ref. port
and disabled 22KHz Hi-Band switch on port 4 by
removing the 22KHz coupling capacator shown on 0:35
Entry port: 0:32 C=120pF, L 330uH terminated by a 50 Ohm Resitor. Coupling to the PLL is 1uF
Termination is important if you use a 3dB divider for ext.Ref. GPSDO, XTOC to use one Clock for your SDR-Device and your Low Noise Converter.
I also published a picture on Instagram / b8sqvq5n_lc
If You use ext.25MHz Clock for this LNB and your Pluto-SDR, i got best results using a 13dB Tab addet to my GPSDO. I feed my Pluto with 9dBm ( terminated ) and -2dBm to my LNB.