What spec sheets from what manufacturers?
Please cite actual examples.
Carl
KM1H
----- Original Message -----
From: "KB0NLY" <kb0nly@mchsi.com>
To: "Carl" <km1h@jeremy.mv.com>; "David Craig"
<davidhcraig@verizon.net>; <amps@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@jeremy.mv.com>
> To: "David Craig" <davidhcraig@verizon.net>; <amps@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@verizon.net>
>> To: <amps@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
>>> _______________________________________________
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>>> Amps@contesting.com
>>> http://lists.contesting.com/mailman/listinfo/amps
>>
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