[CTSARA] SF 2 Meter Repeater Status

[Jon Perelstein]

Curt and I went up to Sterling Farms today to see if we could figure out
what was going on with the 2 meter.  We found a couple of interesting
things:

 

1.   There were four (4) loose sheet metal screws inside the repeater
rolling around on the repeater's main board (not the controller.   Any one
of them, or combinations of them, could have been intermittently shorting
out various traces or binding posts on the board.

 

2.  We found some wires on the backplane that could have been touching
against the back panel of the repeater.

 

The screws have probably been loose in there since the amp was re-installed
last May (it was soon after that we first noticed occasional intermittency
in transmissions - which we thought at first was antenna issues but now
realize were not antenna issues).  The screws are not part of the amplifier
and all amplifier screws are accounted for.  There were four empty screw
holes in an internal rack just above the main board, and the four screws fit
those screw holes.  The internal rack is intended to hold some piece of
repeater gear that we don't have in our repeater.  

 

The intermittency got worse in late Oct/early Nov after Curt and I installed
working fans in the repeater - the vibration of the fans coupled with the
airflow created by the fans could have easily resulted in the screws moving
around more and becoming more of a problem.  It's also possible that the
repeater was bumped by someone working on other equipment in the facility -
it's a tight fit in general and our repeater sits directly behind some
important City gear.

 

The screws could not have been dropped into the cabinet from the outside
because they won't fit through the air louvers in the cabinet (which is an
otherwise closed cabinet).  They couldn't have been rattling around loose
inside the repeater when Frank put it together else we would have had
problems long ago. 

 

The wires on the backplane were properly soldered, but perhaps were not tied
down the way they might have been had the club given Curt and Frank good
information as to the conditions to which it would be subjected and
expectations for usage (e.g., primary repeater versus a backup).  

 

It would be a very good idea for someone to organize a half day exercise for
a couple of people to cinch up and tie down the many many individual wires
in the repeater.

 

Let's cross our fingers and hope that our problems were the result of either
the screws or the wires or some combination thereof.

 

73s

Jon