>
>...
>Someone mentioned using a 1000pf cap for the anode bypass. This
>seems like it might be a little on the low side (4% attenuation could
>imply a hundred volts of RF across the power supply on 160 meters).
>
>Mike, W4EF........................
>
Kenwood uses 2000pF for the anode bypass in the TL-922. Operating on
160m will eventually destroy the filter cap in the positive 110v power
supply. Additional bypassing fixes the problem. The electrolytics in
the HV supply are protected by individual bypass caps.
end
>----- Original Message -----
>From: "measures" <2@vc.net>
>To: "jeff millar" <jeff@wa1hco.mv.com>; "AMPS" <amps@contesting.com>
>Sent: Sunday, October 15, 2000 7:52 PM
>Subject: Re: [AMPS] a sticky issue.
>
>
>>
>> >
>> >Someone is certainly confused here.
>>
>> Amen, Jeff.
>>
>> >The HF RF bypass cap will
>> >reduce 1.8 MHz ripple on the electrolytics. The problem with
>> >ripple currents in the electrolytics has to due with resistive heating,
>> >The designer usually sizes the caps to meet a ripple current heating
>> >specification and if that ripple increases due to plate voltage swing
>> >leaking back through the plate choke, the PS filter caps will operate
>> >at increased temperature and somewhat reduced life.
>> >
>> >jeff
>> >
>> >----- Original Message -----
>> >From: "measures" <2@vc.net>
>> >To: "AMPS" <amps@contesting.com>
>> >Sent: Sunday, October 15, 2000 7:31 PM
>> >Subject: Re: [AMPS] a sticky issue.
>> >>
>> >> >In my determination, the ripple in the supply at 1.8 MHz is about
>> >> >1/2 of a percent when actual impedances are considered. Hardly
>> >> >enough to worry about.
>> >> >
>> >> Adrift in a sea of misunderstanding. // RF voltage on electrolytic
>> >> filter caps is the main concern.
>> >>
>> >> >What major performance changes do you expect to see, if the 1/2
>> >> >percent ripple is reduced from .5% to say .08 %?
>> >>
>> >> The HV RF bypass cap Has Nothing to do with ripple, Tom.
>> >>
>> >> > Or is this a "feel
>> >> >better mod"? (Nothing wrong with that, as long as it doesn't hurt
>> >> >anything else)
>> >> >
>> >> .... clueless
>> >>
>> >> end
>> >>
>> >> - Rich..., 805.386.3734, www.vcnet.com/measures.
>> >> end
>> >>
>> >>
>> >> --
>> >> FAQ on WWW: http://www.contesting.com/FAQ/amps
>> >> Submissions: amps@contesting.com
>> >> Administrative requests: amps-REQUEST@contesting.com
>> >> Problems: owner-amps@contesting.com
>> >>
>> >>
>> >
>> >
>> >--
>> >FAQ on WWW: http://www.contesting.com/FAQ/amps
>> >Submissions: amps@contesting.com
>> >Administrative requests: amps-REQUEST@contesting.com
>> >Problems: owner-amps@contesting.com
>> >
>> >
>>
>>
>> - Rich..., 805.386.3734, www.vcnet.com/measures.
>> end
>>
>>
>> --
>> FAQ on WWW: http://www.contesting.com/FAQ/amps
>> Submissions: amps@contesting.com
>> Administrative requests: amps-REQUEST@contesting.com
>> Problems: owner-amps@contesting.com
>>
>>
>
>
>--
>FAQ on WWW: http://www.contesting.com/FAQ/amps
>Submissions: amps@contesting.com
>Administrative requests: amps-REQUEST@contesting.com
>Problems: owner-amps@contesting.com
>
>
- Rich..., 805.386.3734, www.vcnet.com/measures.
end
--
FAQ on WWW: http://www.contesting.com/FAQ/amps
Submissions: amps@contesting.com
Administrative requests: amps-REQUEST@contesting.com
Problems: owner-amps@contesting.com
|