Re: Pluto QO-100 and SDR Radio- changing ref frequency question

Chris Wilson

Hello Simon,

Thursday, April 8, 2021

Thanks Simon, my take, which may very well be wrong, is you can inject most any frequency into the Pluto instead of using the stock xtal oscillator, (you remove, or bypass the xtal oscillator), and in the firmware you tell it what new frequency you are injecting and it does "magic digital things" to use the new frequency.

My hopefully soon to arrive set up from the Czech Republic sends 25Mhz through a special Bias T to the Pluto, derived from a 10MHz GPS locked source. It also sends this to the LNB to lock that.

I am confused whether SDR Radio needs to be told of this or not, somewhere in your great software's extensive menus was mention of the 40MHz reference, although I can't just find it again right now, which worried me as to whether it would be happy with the Pluto receiving a 25MHz source. It did not appear that changing the 40MHz figure was possible...

Going to take a Paracetamol and reflect :)

Best regards,
Chris 2E0ILY

SB> Chris,

SB> I *think* the internal oscillator is always 40MHz, your LNB may use 25MHz in
SB> which case the software will not need changing.

SB> Simon Brown, G4ELI

SB> -----Original Message-----
SB> From: <> On Behalf Of Chris
SB> Wilson
SB> Sent: 08 April 2021 13:44
SB> To:
SB> Subject: [SDR-Radio] Pluto QO-100 and SDR Radio- changing ref frequency
SB> question

SB> 08 April 2021

SB> If I change the reference frequency for my PlutoSDR to allow locking it to
SB> say an external 25 MHz GPS locked source, will SDR Radio accommodate this?
SB> I see no way to change from the stock 40 MHz ref frequency in one of SDR
SB> Radio's menus. Bear with me please, I am new to this....Thanks.

SB> --

SB> Best regards,
SB> Chris

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