[Amps] 6 mtrs:

[Steve Katz]

Yep, things do change.

 

I want to see the spectral analysis of the SB-200 (monoband or otherwise)
operating at 750W PEP output on SSB, closing in on IM3-5-7 especially.

 

When I've used this tube, it's provided only about 8 dB power gain.  With
100W drive that's <750W output, at any frequency.  The Cetron "ratings" per
the old data sheet I have is 30 MHz max for full ratings; 7.5 dB gain; 2.4kV
max and 250mA max per tube, yielding 300W output per tube (the data
obviously assumes 50% efficiency).  At even 65% efficiency to achieve 750W
out would be 1153W in, and 403W dissipation from a pair of tubes rated for
320W max dissipation at 30 MHz.

 

I fully agree anything's possible.

 

WB2WIK/6

 

 

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From: Gudguyham at aol.com [mailto:Gudguyham at aol.com] 
Sent: Tuesday, September 25, 2007 1:28 PM
To: stevek at jmr.com; la7sl at online.no; amps at contesting.com; km1h at jeremy.mv.com
Subject: Re: [Amps] 6 mtrs:

 

In a message dated 9/25/2007 12:36:55 P.M. Eastern Daylight Time,
stevek at jmr.com writes:

But driving a pair of 572B's to 750W output  looks to a retired E 
professional
like pushing an old VW beetle to 100MPH would look to an auto engineer:
Risky,- at best :-)
May be I am too conservative ??? ...

Hi Steve, the Sb-200 operators manual says that 100 watts is permissible,
Just because you are used to an SB-200 on HF or similar amplifier that with
100 watts makes only about 650 watts out, then why is the same 100 watts of
drive any different on 6 meters?  To me, 100 watts drive is 100 watts drive
either on 80 meters or 6 meters.  I think some of you guys have to think
"outside the box".  When one fine tunes a design and makes it specific for a
specific frequency we are talking a horse of a different color than an all
band amplifier.  Things change.





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