[time-nuts] WTB: GPSDO

Chris Caudle chris at chriscaudle.org
Thu Mar 23 13:15:44 EDT 2017

On Thu, March 23, 2017 9:36 am, Nick Sayer via time-nuts wrote:
> The splitters I’m using do have a 200Ω load on them. I know this
> because PA6H modules recognize an external antenna and use it.

I may have been thinking of a different receiver, according to the
Thunderbolt manual I just checked, the antenna alarm should not "impair
the operation" of the thunderbolt:

Bit 1: When 1, indicates that the antenna input connection is open. More
precisely, this bit indicates that the antenna input is not drawing
sufficient current. Normally, the ThunderBolt provides power to the
antenna’s LNA (Low Noise Amplifier) through the center conductor of the
antenna cable. On-board circuitry senses this current draw, and if low,
this condition will be indicated. However, when the antenna is powered
elsewhere (e.g. when using a splitter) then an antenna open condition is
expected and does not imply a fault nor does it impair the operation of
the ThunderBolt.

Chris Caudle

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