[BC] Noisy transmitters

[Chuck Lakaytis]

Yes, the Z is a pretty quiet box.  It is noisy when it first starts up with
the blowers running at warp speed.  But then they reduce speed if everything
is ok and are quiet.  The blowers will also go to high speed after various
faults are detected, such as a momentary power failure.

Chuck Lakaytis
Director of Engineering
Alaska Public Broadcasting, Inc.
Anchorage, Alaska
907 277 6300
907 310 4339 (cell)


-----Original Message-----
From: broadcast-bounces at radiolists.net
[mailto:broadcast-bounces at radiolists.net] On Behalf Of Richard Fry
Sent: Tuesday, January 03, 2006 11:29 AM
To: Broadcast List
Subject: [BC] Noisy transmitters

Yea?  You should hear a Harris FM-25K.  I have heard UHF TV transmitters
with the heat exchanger that were quieter than that rig.  Heaven help you 
if
you have a 25K and Z series rig in the same room.  Harris has got to have
the loudest transmitters on the market now.
_________________

The old FM-25K had a noisy blower, true.  But the air system in that tx was 
redesigned over 15 years ago when switching to the 600 watt MOS-FET IPA, 
and at the same a lot of backpressure was removed from the PA ductwork. 
The blower speed/horsepower needed to cool the new layout was far less, and 
it was far, far, quieter then.

All of the Harris HT-xxCD single tube txs are considerably quieter than the 
original FM-25K, probably quieter than most others of equal power rating, 
and they have been for a long time now.

Also the Z txs start out with the blower in high speed, and then for normal 
conditions it drops to a much lower/quieter mode within 20 secs or so.

RF 



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