I have a LimeNet-Micro which I would like to access the QO-100 satellite. For reception I use a LNB that requires a stable 25 MHz reference clock inserted and power through the same coax connector. For this I have a Bias-T and reference injector circuit. I have a GPS antenne connected to my LimeNet-Micro to control the internal clock. This gives a reference clock of 30,72 MHz. Is there a way to set this to the desired frequency of 25 MHz or do I need external circuitry?
An alternative would be to generate this signal and send this on the Rx channel that will be coming from the LNB. Is this feasible?
Love to hear from anyone
Alle PE0AJF
What version of LimePSB RPCM board is used in your LimeNet-Micro?
At the moment I am using the LimeNet-Micro v2.1 with a RP-CM4s and a heatsink. Gives a better performance than a CM3.
Alle PE0AJF
@Zack it’s an original LimeNET Micro board and not PSB-based.
I can not think an easy solution off to provide 25 MHz, sorry. Unless you replace an on board oscillator to 25 MHz instead of 30.72 MHz.
One possible solution would be to generate 25 MHz using FPGA PLL (reference clock for this PLL will be 30.72 MHz) and output it to FPGA GPIO. This will require FPGA gateware modification. And not sure if performance will be enaough for your application.