Re: Octagon LNB

Brian Flynn GM8BJF

Hi Mike,
I have taken the 27 MHz xtal out of my octagon and made an external input using the second F-tyle socke as described by Bernie 'HJW.
I have a waterproof box externally which contains a 27 MHz VCXO based on a varactor tuned Colpitts osc which I have locked to 12.8 MHz ex-cellphone
TCXO.  The PLL uses an ADF4113 with a band width of about 10 Hz. I feed about +10 dbm into the  LNB.  The water proof box with the PLL conrtains a Bias Tee to draw the DC off the LNB feed to power the PLL  I am powering the LNB/dish from a cheapo freesat box which allows Polarisation switching and Hi/Lo band switching.
A byproduct of it is I now get Sat TV as the 60 CM dish I am using is wide enought to pick Astra as well!! The 10706 MHz beacon is about 25 db out of the noise.  There is still a slow drift with temperature but it is only a couple of kHz and I can live with that until I find a better TCXO.

Brian GM8BJF

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