Re: Experimenting with Frequency Alignment with HF+ DP/SDR# & Leo Bodnar Mini GPS Clk


So that part of it is settled. Now, what do you know about the synthesizer in the AirSpy? (If it is a real AirSpy (VHF/UHF) forget about getting closer than about 7 Hz. That is the smallest step that can be arranged with the synthesizers in the R820T chip. I don't know about the HF+ versions.)


On 20200316 03:09:40, David J Taylor via Groups.Io wrote:
From: Ian DXer
On Mon, Mar 16, 2020 at 08:35 AM, jdow wrote:
Are you absolutely sure Leo's frequency synthesizer is providing you with the precision you think it is?No not certain at all.
Spec says: Long term stability of output signal is defined by high accuracy of GPS Caesium references and approaches 1x10-12 That defines stability. 'Seams' good enough for my purposes.
Would be nice for someone with both a precision calibrated signal generator AND same Leo Bodnar mini GPS freq clock to compare results.
That might be interesting.
Might look later if enthused sufficiently to use the Leo Bodnar signal source with SDR-Console for some testing. At home with a head-cold at the moment. Fortunately not Xi disease!
I checked this morning - no two agree out of three, but likely all OK within experimental error:
Three GPSDO:
Leo Bodnar dual-output 10 MHz and 240 MHz
Jackson Labs LTE Lite Eval board 10 MHz
Rapco GPSDO rack mount 5 MHz
Counter: BG7TBL, 1 second gate
Counter reference: Jackson Labs 10 MHz GPSDO
Rapco 1804M GPSDO
 5 MHz out reads 4.999.999.68
Leo GPSDO (two outputs)
 10 MHz reads 9.999999.99 -
240 MHz reads 239.999.996 - 240.000.000
Counter reference: Internal ovened oscillator
Jackson Labs 10 MHz GPSDO
 10 MHz reads  9.999.999.98 -
Rapco 1804M GPSDO
 5 MHz out reads 4.999.999.69
Leo GPSDO (two outputs)
 10 MHz reads 9.999999.97 - 9.999.999.98
240 MHz reads 239.999.996 - 240.000.000
David GM8ARV

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