[BC] Transmitter failures

[Mike McCarthy]

Dave's point is the silver bullet of making tubes obsolete in TX's up to 
30KW.  AM's now run 400 VDC for peak and about 150-175 for the RF PA's.  If 
we can double or tipple the power per device package at FM by using much 
higher voltages,  we should see AC/RF efficiencies jump to 75% or 
better.  Much like AM's.  Thus what is now a 10KW box will be a 15-20KW 
box...power supplies and combiner permitting.  A 20KW combined box of two 
TX's is now a 30KW (or more) box.

MM

At 12:59 PM 4/28/2007 -0400, DHultsman5 at aol.com wrote
>
>In a message dated 4/28/2007 6:24:19 AM Central Daylight Time,
>WFIFeng at aol.com writes:
>
>That's  certainly one of the big benefits of these modern transmitter
>designs!
>The  less off-air time, the better!
>
>
>
>
>*************************
>
>One of the main advantages of solid state  is that not all the eggs  are in
>one or two tubes.   Called "Soft Failure"   loss of  one or two modules only
>reduces power output.  It does not affect the air  sound in other 
>ways.  Simple
>replace the module and back to normal.   In many systems loss of more than 
>two
>modules begins to changed the combiner  system which becomes less efficient
>meaning it makes more heat.
>
>Still one of the problems is that in FM we are still using a 48 volt device
>(MOSFET)  with VHF capability of 88-108 mHz of 300 to 400 Watts analog  Class
>C FM Power.  Depending on your output power it starts with combing  two of
>these devices and going up.
>
>Maybe FM will get a 100 or 200 Volt MOSFET allowing more efficient solid
>state transmitters by making more power per single device using 
>fewer  combiners
>
>Dave Hultsman
>Continental ELectronics
>
>
>
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