[time-nuts] 9390 GPS RX
golgarfrincham at yahoo.com
Fri May 24 11:22:29 EDT 2013
I have owned a similar 9390-5588A with the FRK Rb inside for a few
years now. Although the Rb is quite old, the unit locks in just 3
minutes and finds the GPS time (off by 1024 weeks, 16 sec, UTC) in
four minutes and displays an initial PDOP 03. I have reset the time
to the correct UTC time but after a short period it always reverts
to the original time. If I recall the antenna voltage was +12vdc
and I traced the line and reconnected it to +5vdc. The antenna is
roof mounted and runs through a Lucent GPS ant amp/5-way splitter.
I don't recall which ones it was now but I did have a problem with
2 of these old GPS receivers on the same antenna, apparently
reradiating enough of a signal from the LO or whatever so that it
knocked the other receiver off line.
My version of this vintage 9390 has an added switch on the front
to choose where it gets the 1PPS signal to compare and it has
both an a.c. and a d.c. supply. From what I have seen almost no 2
of these units were exactly the same so it is hard to find an
exact manual and I don't have one at all so it made setting this
unit up kind of difficult. The circuit boards directly in front
of the FRK use wire-wrap connector so they could customized these
units for each end-user.
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