ESE ES-102, Operation And Maintenance Manual, Page: 9 / 22

Page 9
ESE TEST RESULTS
The methods mentioned above are conclusions based upon actual tests performed by ESE and on information
provided by various manufacturers. The performance of your unit may differ due to antenna position and obstructions
to its line of sight, weather/atmospheric conditions, cable length or signal reflections.
Listed below are the best consistent and repeatable performances. That is, they were repeatable performances on a
consistent basis... not just fluke observations.
Caution is recommended: as the GPS Satellites age, their signal strength may decrease and today's cable length
could cause undesirable results at a later date.
The ESE factory conducted several tests which demonstrate how the ES-102’s Antenna can be expected to operate
for given sets of circumstances. All tests were conducted at ESE (in El Segundo, CA) in 1998 and due to the
architecture of the GPS Satellite Constellation, can be considered applicable most anywhere in the world.
Test 1
The first test shows that up to 112' of RG-58 cable can be added to the 16’ 5” without any significant loss in signal.
(Adding 125' impaired the clock's performance.)
Test 2
When using a single LA-12F, in-line amplifier with 150' of RG-58 cable (in addition to the 16’ 5” supplied), the clock
would "lock-on" in a nominal amount of time. (Adding 175' impaired the clock's performance.)
Test 3
Using an ES-AB1A (power divider) and two (2) LA-12F with 100' of RG-58 cable attached to each (216’ 5” total)
permitted the clock to "lock-on" in a nominal amount of time. Adding a third LA-12F with 75' of RG-58 cable did not
impair the clock's performance, however, increasing the 75' to 100' did impair the clock's performance.
Test 4
Using an ES-AB1A (power divider) and four (4) LA-12F with 75' of RG-58 cable attached to each (316’ 5” total)
permitted the clock to "lock-on" in a nominal amount of time. Adding a fifth LA-12F with 25’ of RG-58 cable also
permitted the clock to “lock-on” in a nominal amount of time. Increasing the 25’ to 50’ impaired the clock’s
performance.
All of the tests mentioned above were conducted twice; first with the antenna indoors and second with the antenna
outdoors. (Indoors refers to the ESE factory which is a single story building with a wood ceiling and asphalt composite
roofing. And outdoors, the antenna had a very narrow look at the sky with approximately six feet of clearing between
one-story buildings.)
In all cases, the ES-102 "Locked-on" within fifteen minutes, and in less time when the antenna was outside. ("Locked-
on" refers to starting the clock from a completely "powered down" mode and the ESE Time Code output "catching"
real-time with the "GPS Lock" LED lit.)
Various tests conducted away from the factory show that the exact unit which took five minutes to lock-on at the
factory, may take up to 45 minutes at a different location. Possible explanations for this phenomenon lead us to
believe that atmospheric conditions or poor antenna locations may be responsible.