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Unknown GPSDO but BG7TBL logo on the circuit board and OCXO !

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rfclown:
Looked at 10 MHz output from cold start. It was within 1 Hz in 80 seconds. ALM LED turned off at 5 minutes. Six satellites at that time. Compared with LPRO-101 which does its servo thing for about 200 seconds, then boom, it's there. As TurboTom shows, it settles more, but slowly. As I'm typing this the GPS now sees 12 satellites. I'm measuring this with a BG7TBL FA-2 which is also a recent purchase of mine. I've tweeked the FA-2 reference to the GPSDO also, and I'm very happy with its stability.

Noy:
I want to drive my 2 devices with a 10MHz reference input from my GPSDO.
1. DG922 Rigol: It says 10MHz ref in 1kOhm AC
2. Siglent SVA1032X: It says 10 MHz ref in 50 Ohm. Probably AC? But not sure..

Can i drive both inputs directly from the GPSDO with 1 BNC T Connector + 2x BNC RG316 1m cables? Or do in need a distribution amplifier board?
1k||50Ohm are ~47 Ohm should be ok?

How should i connect the units? Special chain?:

GPSDO -> DG922 + T Connector -> SVA   <-Best one?
GPSDO -> SVA + T Connector -> DG922
SVA<-GPSDO + T Connector -> DG922

Noy:
Surgery done..

My device has now a genuine M9 module.
Sweat a bit while dismounting the fake one but they are using good PCB material -> pads survived!

I checked the timepulse settings the M9 can output both needed timepulses.
Unfortunally its working with 34800 instead of 9600.. (buffer overflow with this baud rate )
Have to find out how to send less data (not nmea 4 and high precision..) on the UART to get the atmel back to work (its checking the output from the GPS module but im unsure what the "trigger words" are to get the LEDs back working.

And there is so much configuration stuff you can do.. Need to find out whats best for the gpsdo of the fancy new stuff..
Glad that everything can be stored in flash..

Maybe the atmel TX line has to be left dismounted but im unsure if the atmel checks the answer to his configuration.
If it is not working.. got already an empty one.. then i will programm one myself.
Glad that everything important is done by HW only housekeeping stuff or?

Would there be some benefit (precision / control speed) if im using a lower / higher frequency ? I know i have to mount the other divider resistors..

thinkfat:

--- Quote from: Noy on December 30, 2020, 12:05:38 am ---I want to drive my 2 devices with a 10MHz reference input from my GPSDO.
1. DG922 Rigol: It says 10MHz ref in 1kOhm AC
2. Siglent SVA1032X: It says 10 MHz ref in 50 Ohm. Probably AC? But not sure..

Can i drive both inputs directly from the GPSDO with 1 BNC T Connector + 2x BNC RG316 1m cables? Or do in need a distribution amplifier board?
1k||50Ohm are ~47 Ohm should be ok?

How should i connect the units? Special chain?:

GPSDO -> DG922 + T Connector -> SVA   <-Best one?
GPSDO -> SVA + T Connector -> DG922
SVA<-GPSDO + T Connector -> DG922

--- End quote ---

A simple passive power splitter could work, that's just three 16.7 Ohm resistors connected to a single node with one leg and to three coaxial cables with the other leg.
You connect the GPSDO to one cable and the other two cables go to you test instruments. But you loose 6dB.

If you want something more sophisticated: I've put together a 4 channel distribution amplifier that you could DIY with a little effort (minimal SMD soldering required).
Forum link: https://www.eevblog.com/forum/projects/my-10mhz-distribution-amplifier

TurboTom:
@Noy:

Your SVA1032X has got a dedicated REF IN and REF OUT, so you may connect GPSDO -> SVA1032X (REF In) and with another BNC cable SVA1032X (REF Out) -> DG992. The only disadvantage of this interconnection is that the SVA needs to be powered up to supply the DG with the ref signal (unless the REF buffer runs from the standby PSU of the SVA).

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