Well, the water here comes out of a 660' deep well and has a bit of iron
in it but none of that funny stuff you get from town water.
Its very easy to get power from 572B's on 6M since they are full power
rated to 54 mHz. I certainly wouldnt run RTTY or digital that way but
CW/SSB doesnt bother them a bit. I test every conversion at 1 minute
full bore key down; the plates get a bit of dark red near the end.
Im not the only one who converts these either.
Carl
KM1H
----- Original Message -----
From: "Jeff Blaine" <keepwalking188@yahoo.com>
To: "Carl" <km1h@jeremy.mv.com>
Cc: "George Knight" <gkve3ltu@sympatico.ca>; <amps@contesting.com>
Sent: Thursday, March 12, 2009 6:20 PM
Subject: Re: [Amps] 810 Amplifier
> Carl,
>
> Can you send us some of whatever is in the water up there? Because
> the SB200's in this part of the world are sure in need of that magic
> elixor.
> What's the plate dis of a pair of 572b? Something like 360w? Maybe
> that is the answer to my question on the other subject of anode dis
> limits...
>
> Clearly a sample size of 250 sb200 converted to 6m service is an
> extreeme case (given the tubes start running out of gas at 30mhz more
> or less) - and a large sample set of 200 statistically is very
> significant.
> If that tube will work at 2x the plate dis in the north east, then I
> surely should be able to get the similar multiplier from my conversion
> project here in the fly-over country.
>
> 73/jeff/ac0c
>
> Carl wrote:
>> My 2 cents anyway. :)
>>
>> Yep, I agree with the above<G>
>>
>> In my experience with converting around 250 SB-200's to 6M I can
>> unequivocally say that a majority still have the original Cetrons
>> installed and will run 700W + key down on 6M on a 240V AC line. A bit
>> less on 120V.
>>
>> Your milage may vary.
>>
>> Altho I feel the 4 x 810 project is a wasted effort it is possible to
>> do it with 4 x 813's and cover 160-10M.
>>
>> Carl
>> KM1H
>>
>>
>> ----- Original Message ----- From: "Jeff Blaine"
>> <keepwalking188@yahoo.com>
>> To: "George Knight" <gkve3ltu@sympatico.ca>
>> Cc: <amps@contesting.com>
>> Sent: Thursday, March 12, 2009 3:21 PM
>> Subject: Re: [Amps] 810 Amplifier
>>
>>
>>> George,
>>>
>>> You may want to consider a trio of GI7B (less complicated) or
>>> perhaps a
>>> 4cx800 (more complicated) if you run something other than SSB.
>>> These
>>> ceramic tubes are far more durable than the glass counterparts in my
>>> experience.
>>>
>>> I bought 3 sets of 572b last year in a test to determine the actual
>>> life
>>> of the 572b vs. duty cycle because the data for contempary versions
>>> of
>>> the 572b are hard to come by. None of the tubes could reach the 25
>>> hour
>>> key-down accumulated time before reaching 500w output for the set.
>>> I
>>> have seen the stories of guys with 500w out on a 25 year old set of
>>> tubes in a SB200, but that is clearly the excepiton and not the
>>> rule.
>>> The 572b at 1200w out of a set of 4 is really something that can
>>> only be
>>> sustaned in the long term if conditions are perfect and the winds
>>> are at
>>> your back.
>>>
>>> So while your mileage may vary, I can say categorically that at
>>> 1200w
>>> out as the goal (meaning net average power, not PEP or peak or
>>> whatever), the 572b set of 4 will do it. But just not for very
>>> long.
>>>
>>> My 2 cents anyway. :)
>>>
>>> 73/jeff/ac0c
>>>
>>>
>>> George Knight wrote:
>>>> Thanks to all who contributed. Although there is a lack of
>>>> unanimity in the responses, I think I will go ahead with the
>>>> project. In the event that it turns out to be a total failure, it
>>>> will be quite easy to change the sockets to accept 572B tubes and
>>>> get into the 1200 watt output class.
>>>> '73, George, VE3LTU.
>>>> _______________________________________________
>>>> Amps mailing list
>>>> Amps@contesting.com
>>>> http://lists.contesting.com/mailman/listinfo/amps
>>>>
>>>>
>>>
>>> _______________________________________________
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>>> http://lists.contesting.com/mailman/listinfo/amps
>>
>>
>
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