[AMRadio] What about SB-200 with FT-101E?


Jose HF Silva zehelmer at yahoo.com
Sat Mar 18 10:48:02 EST 2006


Hi,

I have been using this combination and got some good
reports but I have not a reasonable idea of power
output. 
So I would like to have a good estimation from those
who are better prepared to do it.

Thanks^6

73 de Jose' CT1AXG


Date: Fri, 17 Mar 2006 22:03:50 -0500
From: "kenw2dtc" <kenw2dtc at comcast.net>
Subject: Re: [AMRadio] Amplifier to use with my DX-60
To: "Discussion of AM Radio" <amradio at mailman.qth.net>
Message-ID: <000c01c64a38$95f456c0$0201a8c0 at ken>
Content-Type: text/plain; format=flowed;
charset="windows-1250";
	reply-type=response

Don K4KYV said:

"I hear a lot of guys on the air with AM linears, and
most of the time 
they 
claim to be running way too much carrier  for the
tubes they are using.  
I 
often hear stuff like 200 watts out with a pair of
811A's or 250 watts 
out 
with a pair of 813's in g-g.  If so, they are cooking
the tubes, or 
else the 
efficiency is running too high, and they are 
flat-topping all over the 
place."

I agree with your comments and yes, there is no doubt
that those rigs 
are 
flat-topping.  I've been running linear amps on AM for
years and I find 
that 
the cleanest,  best sounding signal comes from a
linear with LOTS OF 
PLATE 
DISSIPATION and HEADROOM.  In addition, an audio
signal generator and 
an 
oscilloscope are mandatory to get clean results.  Not
everyone has this 
equipment and it is a hobby after all so folks do the
best they can.

As a rule of thumb I consider the plate dissipation
divided by 3 to be 
a 
general yardstick for AM linears, some tubes giving a
little more and 
some a 
little less.  In the case of a pair of 3-500Z's I rate
them in the 
333-350 
watt carrier class.  So while a pair of 813's can be a
wonderful plate 
modulated rig, as an AM linear they are not worth all
the trouble of 
building them.  It seems to me to be a waste of time
to build an AM 
linear 
with much less than 1000 watts of plate dissipation. 
Of course if you 
have 
a low power rice box and already own some kind of
linear, well go 
ahead, but 
if one is building an AM linear,  more dissipation is
better.

73,
Ken W2DTC



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