Shortly after joining time-nuts on Corby's recommendation I announced that
I wanted to build a complete Dual Mixer for less than $ 200. Richard
McCorkle offered to help me with the code for the counters. After completion
we
started talking about GPSDO's which I had previously worked with Brooks
Shera on. We did an extensive methodical review of the system and discovered
serious problems with the the AD1861 when used in a filter application. We
tested many D/As and switched to the LTC1655. Explored dithering.
During that work a German friend that I work with on a different subject
made me aware of the FE5680. At the price I bought a couple and was surprised
at its performance. Though they had been in Europe for a couple of years
I had not seen any thing on time-nuts. I published my observations. At the
same time we started work on a digital controller Richard the code and the
rest of us testing and analysis. A year in to the program I discovered the
FE 405 on ebay and bought 4 for the team. Early on I noticed outstanding
performance that was later confirmed by Tom. Focus was shifted to the 405.
After many iterations we now have a Universal GPSDO based on which PIC we
insert. Works on the FE405, Skip's 5650 and the 5680 that every body
bought out of China. Some time nuts have run units for over a year and I feel
comfortable to have Cash build, test and sell the units soon. Units he build
are presently being tested. We are also assembling a documentation package
that will be on his web site.
Depending what the interest is there also will be an auxiliary board for
the 405 with a divider and output filter for 5 MHz, DC/DC converter,
regulators and a PIC for display purposes. This board will not be assembled
but
comes with two MC output transformers since small purchase will not be
economical. All other parts will be readily available.
An analog temperature control board, board only will also be available.
All boards a 5 X 5 cm and stack able.
There was talk about a digital fan control hope some one will step up to
the plate.
Hope this answers your question.
Bert Kehren
In a message dated 12/12/2015 11:00:46 A.M. Eastern Standard Time,
jsrobb...@earthlink.net writes:
Bert,
For those of us who are not familiar with your work, but who have
purchased one of Skip's FE 405s, could you summarize what work you and your
group
have done on the "FE 405/5680/5650"?
You say "Cash Olsen will be responsible for the sale of assembled and
tested units." What assembled and tested
units are you referring to?
Many thanks.
Jim Robbins
N1JR
Can be directly emailed at call @arrl.net
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