On Tue, 12 May 98 21:25:02 -0800 Rich Measures <measures@vc.net> writes:
>>
>>On Tue, 12 May 98 09:27:20 -0800 Rich Measures <measures@vc.net>
>writes:
>>>>Rich writes:
>>>>
>>>>>>there's a bit more to designing a VHF-suppressor than Q.
>>>>Absolutely true. The actual reactances of the pi or pi-L network
>are
>>>
>>>>critical,
>>>
>>>The average HF tank is a low-pass filter, so how does VHF-energy get
>
>>>past C-Tune? .
>>>- thanks
>>
>>Very simple if you bothered to analyze a real circuit....not just
>theory.
>>The SB-220 is a prime example of what you claim does not exist.
>>
>What is the real analysis, Carl?
Explain your idea of real Rich; please.
I believe that Tom explained it fairly well. BTW welcome back Tom. I
would also add that every amp is different and you cant sit down with a
paper analysis that covers them all.
You have shorting and non-shorting coil taps, Pi's and Pi-L's, widely
varying physical layouts. IMO, you are just blowing gas without sitting
down with a spectrum analyzer, GDO, RF probes, etc. to characterize each
and every amp you want to claim to be an expert on.
I consider myself a generalist just based on limited experience. I'm not
an expert and I certainly do not have the experience or data base of a
tube or amp manufacturer.
If a high order 10M harmonic is only 30dB down (older design amps) at the
analyzer then do some mental gymnastics and figure where the other KW or
so is being absorbed. If you happen to say the tune cap/bandswitch/ tank
coil, you may just have won a prize. By the time the "bad RF" gets to the
loading cap it has already done its damage. Just look at the tank coil as
similar to a plate choke with a mess of series and parallel resonances
caused by the switch, coupled C and L and even the shape/size of the
enclosure.
With modern FCC spec amps tell me where that 50+ dB is going Rich?
Wouldnt you begin to suspect that the better the harmonic attenuation in
the tank circuit the more stress on the components? Would that not
partially explain the propensity of some of our newer amps to have major
pyrotechnics in the switch and tune cap?
73 Carl KM1H
>- thanks
>
>
>cheers
>Rich...
>
>R. L. Measures, 805-386-3734, AG6K
>
>
>--
>FAQ on WWW: http://www.contesting.com/ampfaq.html
>Submissions: amps@contesting.com
>Administrative requests: amps-REQUEST@contesting.com
>Problems: owner-amps@contesting.com
>Search: http://www.contesting.com/km9p/search.htm
>
_____________________________________________________________________
You don't need to buy Internet access to use free Internet e-mail.
Get completely free e-mail from Juno at http://www.juno.com
Or call Juno at (800) 654-JUNO [654-5866]
--
FAQ on WWW: http://www.contesting.com/ampfaq.html
Submissions: amps@contesting.com
Administrative requests: amps-REQUEST@contesting.com
Problems: owner-amps@contesting.com
Search: http://www.contesting.com/km9p/search.htm
|