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

Simon Brown


Let's see, at the moment SDR Console only knows about 40Mhz.

Simon Brown, G4ELI

-----Original Message-----
From: <> On Behalf Of Chris
Sent: 08 April 2021 14:53
To: Simon Brown <>
Subject: Re: [SDR-Radio] Pluto QO-100 and SDR Radio- changing ref frequency

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
SB> 25MHz in which case the software will not need changing.

SB> Simon Brown, G4ELI

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

SB> 08 April 2021

SB> If I change the reference frequency for my PlutoSDR to allow locking
SB> it to 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
SB> SDR Radio's menus. Bear with me please, I am new to this....Thanks.

SB> --

SB> Best regards,
SB> Chris

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