[Amps] SB200 on 6m & my take

[Carl]

What spec sheets from what manufacturers?

Please cite actual examples.

Carl
KM1H


----- Original Message ----- 
From: "KB0NLY" <kb0nly at mchsi.com>
To: "Carl" <km1h at jeremy.mv.com>; "David Craig" 
<davidhcraig at verizon.net>; <amps at contesting.com>
Sent: Friday, March 13, 2009 11:36 AM
Subject: Re: [Amps] SB200 on 6m & my take


> Since all the spec sheets from all the manufacturers said so.  They 
> hardly hold their own at 10m.
>
> 73,
>
> Scott
>
>
> ----- Original Message ----- 
> From: "Carl" <km1h at jeremy.mv.com>
> To: "David Craig" <davidhcraig at verizon.net>; <amps at contesting.com>
> Sent: Friday, March 13, 2009 8:45 AM
> Subject: Re: [Amps] SB200 on 6m & my take
>
>
>> I'll be briefer. Since when isnt the 572B rated to 6M?
>>
>> Carl
>> KM1H
>>
>>
>> ----- Original Message ----- 
>> From: "David Craig" <davidhcraig at verizon.net>
>> To: <amps at contesting.com>
>> Sent: Friday, March 13, 2009 12:44 AM
>> Subject: [Amps] SB200 on 6m & my take
>>
>>
>>>    Brief & to the point- they stink, monoband or (worse) tapped
>>> bandswitch "models".  They may be fine for the occassional SSB QSO
>>> without pushing it, but otherwise they do one thing with regularity-
>>> they die/burn out/self-destruct.  RTTY? WSJT & other digicrap with
>>> 100% duty cycle for 30-55 seconds key-down?  Result?  Be ready for a
>>> buzz, hiss, POP & Boom & to buy a new amp, or parts that cost enough 
>>> $
>>> to build a new one.  I don't do any digital myself save cw but if 
>>> you
>>> want a list of dead SB200 conversions (owned by others) I'll be 
>>> happy
>>> to provide them, some were EME deaths & others that just "crapped 
>>> out"
>>> due to tubes that aren't ment to be used at that QRG.
>>>    I don't care what you can "get away with", I want something that
>>> isn't going to crap out because the tubes aren't rated for 50MHz 
>>> use.
>>> SB200s should be left to HF.  If you are still going to convert one,
>>> do what I am doing and put a 3CPX800 in it with new cooling and a 
>>> new
>>> FWB PS and appropriate transformer.  Otherwise build one with an
>>> appropriate tube/s from scratch which I have also done x 3.  572Bs 
>>> are
>>> a lousy tube for 6m conversion unless your habit is to run it a few
>>> hours per year.
>>>    Oh, one last thing- for parasitic suppressors, don't be lazy and
>>> use the resistor leads as a soldering surface for the L (really a 
>>> "U")
>>> between resistor sides on a 6m conversion.  I have seen 4 cases so 
>>> far
>>> of that method resulting in heat melting the "L" on the plate-block
>>> side... ergo all B+ plus RF current passes thru the resistors &
>>> softens the tubes in seconds. $600+ $ down the tubes.
>>>
>>>    N3DB
>>> _______________________________________________
>>> Amps mailing list
>>> Amps at contesting.com
>>> http://lists.contesting.com/mailman/listinfo/amps
>>
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>
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