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

Peter Markavage manualman at juno.com
Sat Mar 18 14:05:10 EST 2006

I've been using a SB-200 with various rigs (C.E. 100V, Laf. HA-410 (on
10, when 10 was hot), Icom 756 PRO II, Icom IC-706 MKIIG, Johnson Ranger,
and Kenwood Twins on AM for the last 15 years. Sometimes I use the
Johnson Courier as an alternative  to the SB-200. Courier also runs with
572B's. Simple to use, simple to interface, provide an extra fan on top
of the SB-200 to exhaust the heat. The SB-200 is a great workhorse. Still
using the same 572B's that were put in it in 1969. I generally run the
output between 100 and 130 watts.

Pete, wa2cwa

On Sat, 18 Mar 2006 07:48:02 -0800 (PST) Jose HF Silva
<zehelmer at yahoo.com> writes:
> 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 
> 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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