Will the 6 meter guys publish some pics&specs for their work on the web?I
want to see their work...No,I`m not interested in copying their
designs...All this "Discussion" deserves some real show&tell...Jim K7RDX..
----- Original Message -----
From: "Tom Rauch" <w8ji@contesting.com>
To: <amps@contesting.com>
Sent: Tuesday, September 25, 2007 5:06 AM
Subject: Re: [Amps] 6 mtrs:
> > On another note, Carl and I have seen many failed attempts
> > to SB-200
> > conversions to 6 meters and we have fixed them. Some
> > people who can't seem to get
> > it together with an Sb-200 conversion to 6 meters, cop out
> > and say it can't be
> > done or blame the tubes or some other lame excuses. Then
> > go on to try and
> > convince the masses that it is not a good item to buy. I
> > am sure Carl and I
> > can come up with hundreds of satisfied customers. Might I
> > add W2CQM to the
> > list.
>
> It could be you are doing enough wrong that it works, and
> they are doing so much right it doesn't work.
>
> That's what happens when we use a device in a region where
> it is unstable.
>
> The problem comes in when we inflate ourselves and be openly
> critical of others when we really succeeded through luck.
>
> Here is the test.....
>
> Take a pair of 572B's and put them in a near-perfect layout
> with very short grid leads, a very short anode path to the
> tank, and good shielding.
>
> Does it dip in the center of the RF power peak?
>
> Is it unconditionally stable for all tuning conditions?
>
> The answer above about 15MHz with the 572B in a pair is NO.
> As a matter of fact a well shielded design will oscillate if
> lightly loaded at full anode voltage. It will also NEVER
> have the output peak anywhere close to minimum anode
> current.
>
> Now if we go higher, especially in a much less than perfect
> layout, we can find frequency bands of stability. The
> problem is when we credit our accident to great skill and
> ability and heap tons of bad verbiage on others because they
> had what really amounts to bad luck, or we start saying the
> tube manufacturer is wrong.
>
> Rejoice in the fact you have found a good recipe, but let's
> not slam others who very likely could be just as
> knowledgeable or more knowledgeable than you or Carl. They
> just might not be as lucky as you two.
>
> 73 Tom
>
>
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