[time-nuts] Trimble Thunderbolt and David Partridge divider board question

Chris Caudle chris at chriscaudle.org
Mon Oct 12 16:25:40 EDT 2015

On Mon, October 12, 2015 9:08 am, Chris Wilson wrote:
> I have found when the TX is on at 136kHz the Trimble / divider
> baord output goes wild and a clean square wave goes seemingly random
> on my scope with noise.

How are your input and output cables physically configured?  I noticed on
the link that Dave just posted that he uses a divider board inside a
conductive enclosure, and the input connectors are fed from short coax
cables which have their shields all connected to the same metal panel of
the enclosure.
The printed circuit board has input and outputs on opposite ends of the
board, and the connector shells appear to be connected to the circuit
reference conductor, which means that if the input and output cable
shields are not close together and connected together electrically very
well, all the shield current will be forced to flow across the printed
circuit board reference conductor.  Perhaps with your transmitter
operating so closely it is resulting in a lot of ground bounce at the
various components on the divider board.
As you say, connecting the 10MHz directly without the divider in place
would help confirm or eliminate that possibility.

Chris Caudle

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