[time-nuts] FE-5680A word of caution

WB6BNQ wb6bnq at cox.net
Thu Apr 7 22:41:50 UTC 2011


Jerry,

What reference and measurement system are you using to determine the frequency
values you are quoting ?

Bill....WB6BNQ

Jerry wrote:

> Just a word of caution to possible buyers of the Chinese Rubidium
> FE-5680A boxes.
> There has been a lot a discussion on the list lately about using the
> popular FE-5680A as a portable frequency standard and I have being
> working on using one of the cheap FE-5680A boxes myself.  I have found
> that many of them do not output a useful 10 MHz signal.  The 10 MHz
> output is not close to the expected frequency tolerance.  The first of
> the units that I received puts out a signal at 9,999,945 Hz.  The
> vendor then sent a second unit which puts out a signal at 10,000,025
> Hz.  The vendor is in China and while he has been willing to work with
> me by sending a second unit with me paying only postage, the time
> delay in shipping from China and the cost of postage is prohibitive.
> What concerns me the most is that the vendor says that both units were
> tested before shipping.  In reviewing the Internet I found several
> other reports of similar problems with FE-5680A units.  The units that
> I have been working with are FEI FE-5680AFEI P/N 217400-30352-1.
> These units all require a 5 volt input in addition to the 15 to 18 vdc
> input and these units are not programmable via an RS-232 port.  These
> units are being advertised by several vendors on E-bay.  I am sure
> that there are good FEI units available but there is no way of telling
> which are good and which are bad until you get the unit and check it
> out and if it is bad you may just be stuck with it,  Only my
> experience yours, may be different
> Jerry
>
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