Hi, On Wed, Mar 22, 2017 at 05:20:31PM -0500, Chris Caudle wrote: > On Wed, March 22, 2017 3:52 pm, Nick Sayer via time-nuts wrote: > > My thunderbolt *insists* on being on the DC Pass port. If you put it on a > > DC Block port (yes, something *else* is on the DC pass port and supplying > > DC for the antenna and splitter at the time - other connected devices work > > just fine) it's deaf. > > You need a DC load so that the GPS receiver thinks there is an active > antenna attached. I think that is just a quirk of the Thunderbolts, that > rather than just flagging an alarm and continuing to run, it gives up and > won't even try to run.
They try to check if an active antenna is connected by measuring the DC load. You can (not tested by me) simulate this with a Bias T and a resistor to ground on the DC port. I think there are more receiver that might require this. Many dedicated GPS splitters have such a DC load 'simulation' with around 200 Ohm to ground to keep the receiver happy. Best, Thomas DK6KD/SA6CID > -- > Chris Caudle > > > > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. >
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