The point that I have been proving for almost 40 years is that the SB-200 is
an excellent candidate for 6M. Dollars per watt it is the best deal around
and a preferred choice by many who do not want to install a 240VAC line into
the shack. The 572B's work fine and last a long time which is really what
its all about.
Since the output and efficiency is comparable with mid HF I doubt if 50 MHz
is actually that close to the upper limit. I suspect that it is an
arbitrarily set number.
There certainly is no magic to making sweep tubes work on 6M either. Ive
converted several 2-3 tubeCB amps. There was an engineer at National that
converted many NCX-3's to 6M also so the precedence was set over 40 years
ago.
And dont forget the Drake TR-6 using 3 6JB6's; it worked very well and is
still a sought after rig.
Carl
KM1H
----- Original Message -----
From: "Tom W8JI" <w8ji@w8ji.com>
To: <Gudguyham@aol.com>; <km1h@jeremy.mv.com>; <amps@contesting.com>
Sent: Tuesday, July 17, 2007 10:11 PM
Subject: Re: [Amps] SB-200 DATA
>I> In a message dated 7/17/2007 7:48:51 P.M. Eastern Daylight Time,
>> km1h@jeremy.mv.com writes:
>>
>> Converting the SB-200 to a 6M monobander is simple and straightforeward
>> when
>> basic design principles are followed. Ive been doing those conversions
>> since
>> the late 60's and it is completely stable and repeatable. Power output
>> and
>> efficiency is the same or better than a good stock unit on say 20M.
>>
>> Carl
>>
>>
>>
>> Carl, Indeed, the word on the street is that the 572B is not good to 6
>> meters, but as you say if it is handled properly it can be made to be
>> rather
>> stable and the power in the 700 watts range easily. I haven't really
>> seen a
>> published article that really "gets it right" however. Lou
>
>
> I think you fellows are missing the point entirely. There is a BIG
> difference between "I can make it work" and "it is a good choice".
>
> I can make a sweep tube work on six meters, but it doesn't mean it is a
> good choice in tubes for six meters.
>
> Using a tube right at the upper limit frequency isn't the best idea,
> unless you just have no other choice or are trying to prove a point.
>
> 73 Tom
>
>
>
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