[time-nuts] Lucent RFG-RB

Rex rexa at sonic.net
Thu Dec 28 03:22:35 EST 2006


I just received a Lucent RFG-RB (no -m- in this one) rubidium unit eBay
buy from the lady in Atlanta. Thought I'd share a few notes on what it
is. Maybe some of this has already been covered -- I lost track of all
the emails.

Like John, I immediately opened it up, haven't tried it yet, and won't
for a while.

No GPS, as has been noted in the other messages, that seems to be in the
crystal unit. This one was made in 2000. Inside mine, the main component
is a Datum LPRO 102500. Seems to be functionally identical to the one in
the manual here:
http://www.symmetricom.com/media/pdf/manuals/man-lpro.pdf

Box front panel:
3 sma's - TP (J1), 10 MHz RF Out (J2), 15 MHz Out (J4)
3 db9's - +24V (P1), Alarm (J3), Interface (J5)
3 led's - Fault, Stby, On

Seems the +24V connector only uses two pins: 1 = +24, 2 = return/gnd
I assume those two are all that's needed to make it run.

Main board is made by Efratom.

I don't see any connection to the rubidium C-field pin so I don't think
there is any adjustment through the main board, just the adjustment thru
the case of the LPRO.

With some tracing, I can't figure where the 10 MHz output (sma) comes
from. I assume it is functional, but haven't applied power yet. 

The 15 MHz generation looks very similar to the other boad I described
in another message on an FRS-C unit. The active source again seems to
come from an Altera PLD. Maybe it divides 10 MHz by two, and (guess)
narrows the pulse for better 3rd harmonic? Anyway, then it seems to go
through a series resonant LC, with a trimmer on the C. Then thru the 15
MHz filter, two stages of amplification, and a MCL low-pass filter to
the sma.

BITE signal from the LPRO goes somewhere so I assume it is at least part
of the alarm connector output.

If anyone finds or works out the pins on the alarm and interface
connectors, I'd eb interested to hear about it.

So there we are for now. Quick first look without even trying it yet.
Assuming it works, the LPRO was probably worth my $130 investment. Hope
some of my comments helps someone.

-Rex




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