need DX-100 advice

[Glen Zook]

First of all, you are pushing the final amplifier
tubes WAY too hard!

Maximum input to the finals on CW would be 180 watts. 
However, for maximum tube life you need to reduce that
to no more than 150 watts.  At 180 watts input you
should get around 110 watts output on 80 meters and
probably about 90 watts output on 10 meters.  At 150
watts input you are going to get about 90 watts output
on 80 meters and about 75 watts output on 10 meters.

On AM phone the MAXIMUM input power to a 6146 is 67.5
watts (this per RCA specifications) which means a
MAXIMUM input on phone to the DX-100 (with the pair of
6146 tubes in the final) of 135 watts.  At this power
level you should be running about 80 watts output on
80 meters and about 70 watts output on 10 meters.  A
better power level is 120 watts which will give a
little over 70 watts output on 80 meters and about 60
watts output on 10 meters.

With new tubes you might get a few watts more output. 
However, running the tubes at maximum ratings does
nothing for your signal report from the other station
but does reduce the life of the 6146 tubes
substantially.

Again, the station on the other end is not going to be
able to tell the difference between 180 watts or 150
watts on CW or 135 watts or 120 watts on AM.  But,
your final amplifier tubes definitely will know it and
will last substantially longer at the slightly reduced
power.

For the article on the 6146 family of tubes that
appeared in Electric Radio a while back go to 

http://k9sth.com/Page_2.html

and the 6146 article is the first under the sub title
of "Articles".

Glen, K9STH


--- "TChesek at Epix.Net" <tchesek at EPIX.NET> wrote:

On CW I measure 125-140 watts, depending on frequency,
into my HM-2140/Cantenna. In the Phone mode I also
measure approximately the same values, carrier...then
when I talk into the microphone the power reading
drops dramatically. If I whistle continually for 5
seconds or so the measured power will drop to around
30 watts.









Glen, K9STH

Website:  http://k9sth.com

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