Robert Darby
2013-04-03 18:53:55 UTC
I purchased an FTS 1050 recently and after a cursory inspection of the
interior powered it up to see if it's functional.
This particular unit is a bit odd; it has the optional battery back-up,
no PPS, and instead of the usual 1Mhz, 5Mhz, 10Mhz it has four 10Mhz
outputs with tnc female connectors.
The tnc connectors are a bit of a bother but I found that the scope
probe sleeve that fits a bnc also fits into a tnc so I'm able to view
the outputs. They are not pretty, lots of hash, particularly at the
zero crossings and only about 15 to 20mV rms. That's the case for all four.
The oscillator is an FTS 1000B-503 which is supposed to have four
buffered outputs at 5MHz; two at 1.0 V rms and two at 0.5 V rms. Two
outputs each drive a pair of frequency doublers that thus provide the
four 10Mhz outputs. I got a connector on one of the spare outputs to
see if the problem might lie in the oscillator. What I see there is a
very stable clean sine wave at 5MHz at about 660mV rms so I'm assuming
the 1000B is not my problem.
The doublers are housed in a tidy box adjacent to the oscillator with
22V and ground, two 5MHz inputs and four 10MHz outputs all in the top
cover. There is a stone cold 7818 in a TO-3 metal can mounted on one
side of the box but no external connections other than those previously
noted. It seems to me my problem must lie in this area and, since all
four circuits are similarly affected, is probably related to the power
supply housed therein.
This is probably obvious to all of you but I'm a toolmaker by trade so
this is all new to me and second opinions will not hurt my feelings.
Also does anyone have any experience inside of the doubler box or a
schematic of the standard (or any other version) doubler/divider for
these things?
Thanks for any insight anyone can offer.
Bob Darby
interior powered it up to see if it's functional.
This particular unit is a bit odd; it has the optional battery back-up,
no PPS, and instead of the usual 1Mhz, 5Mhz, 10Mhz it has four 10Mhz
outputs with tnc female connectors.
The tnc connectors are a bit of a bother but I found that the scope
probe sleeve that fits a bnc also fits into a tnc so I'm able to view
the outputs. They are not pretty, lots of hash, particularly at the
zero crossings and only about 15 to 20mV rms. That's the case for all four.
The oscillator is an FTS 1000B-503 which is supposed to have four
buffered outputs at 5MHz; two at 1.0 V rms and two at 0.5 V rms. Two
outputs each drive a pair of frequency doublers that thus provide the
four 10Mhz outputs. I got a connector on one of the spare outputs to
see if the problem might lie in the oscillator. What I see there is a
very stable clean sine wave at 5MHz at about 660mV rms so I'm assuming
the 1000B is not my problem.
The doublers are housed in a tidy box adjacent to the oscillator with
22V and ground, two 5MHz inputs and four 10MHz outputs all in the top
cover. There is a stone cold 7818 in a TO-3 metal can mounted on one
side of the box but no external connections other than those previously
noted. It seems to me my problem must lie in this area and, since all
four circuits are similarly affected, is probably related to the power
supply housed therein.
This is probably obvious to all of you but I'm a toolmaker by trade so
this is all new to me and second opinions will not hurt my feelings.
Also does anyone have any experience inside of the doubler box or a
schematic of the standard (or any other version) doubler/divider for
these things?
Thanks for any insight anyone can offer.
Bob Darby