[BC] BE AM-1A Transmitter Air filter Heads-up!!

[Craig Healy]

I used two sets of air filters on a transmitter I built some time ago.  On
each end of the cabinet were four common household type air filters.  Since
the area was so large, the air velocity and pressure was very low.  When a
filter is used in that fashion, it is much more effective.

The secondary filters were put directly on the input of the 2hp blower used
to cool the final tube.  Initially I used a pair of Fram filters.  The part
number was for a common Chevy truck with a 350 engine.  Some time after that
I swapped them for a pair of aftermarket K&N filters.  They did flow better
and lasted much longer.  And, they were able to be cleaned and reinstalled.

The 8 end filters lasted for over five years before any significant dust was
noticed.  The 2 original Fram blower filters lasted six months or so before
the pressure differential was 2" or so.  The K&N lasted years.

This rig was the main transmitter at a previous client for maybe 15 years.
In that time the inside of the final amp cabinet barely showed any dust at
all.  Inside the main cabinet also accumulated almost no dust.  The room
that it was in originally was pretty dirty, so it wasn't the environment.

Pictures of the transmitter including the blower filters.
http://www.craighealy.com/xmtr.htm

Since then I have used much larger filters on some transmitters.  In some
cases simply putting them over the factory ones.  Always worked well and
saved work.

Many automotive air filters today are simple flat types.  They could easily
be adapted to transmitters.  The aftermarket types flow much better and last
longer.  Frankly, I'm surprised transmitter manufacturers don't simply use
one from a common vehicle that will be around for a long time.  Much easier
to find and should work a lot better.

Craig Healy
Providence, RI