[time-nuts] Re: 10 MHz Distribution Best Practices

[Ulf Kylenfall]

In my previous workplace, the Hydrogene masers as well as the distributors for frequency and time
(clock ticks) is placed in a room with controlled temperature and humidity. The distribution hardware
is designed using SMA connectors for I/O. The only other approved connectors are TNC or N. 
Timing is checked and compared to the UTC center in France. Until recently, the two
masers were amongst the most stable in the world and was often selected to be contributors to
the group of 10 that defined the UTC.

All outgoing mission critical cables are either coax with solid screen or a mixture of braid and copper foil
such as CNT-400 or CNT-400-Flex. Cables routed to remote locations are buried deep in the ground to keep
variations over the day in phase or timing at an absolute minimum. Our requirements is to be able
to measure cable delay and cable delay variation differences in the order of picoseconds at distances
over several hundred meters.

Ulf Kylenfall, SM6GXV
Sr Research Engr, (Ret.)
Onsala Space Observatory,
Chalmers University of Technology
Onsala, Sweden.