Last night I hooked hooked up my HPZ3801 GPS clock. Everything seemed to be
working fine. It was tracking 5 or 6 sats and the Ext Ref light on the RX340
was on.
This morning I noticed that the clock had switched to holdover mode. Running
the SatStat software, I saw that it wasn't tracking any sats, even though it
thought 7 were visible and it was trying to track 6 of them.
Suspecting the extension cable that I had made to get the signal from the
antenna to the clock in the shack, I measured the DC voltage at the point
where the antenna cable connects to the extension cable. With the antenna
disconnected, I measured 4.82 V. With the antenna connected, the voltage
dropped to about 40 mV.
I measured the DC resistance of the antenna and got 13 ohms. I have no idea
what it should be, but that seems low. With 5 V and 13 ohms, you have a
current of almost 400 mA. It's not suprising that that loads down the
clock's 5V supply. Does anyone know what the current draw of the antenna is
supposed to be?
73,
Mark
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