[AMPS] Diodes
measures
2@vc.net
Tue, 22 Feb 2000 11:33:40 -0700
>
>> I was reading the HF amps section the other day, and was surprised to read
>> the flat statement that the filament choke is not necessary in
>> grounded-grid amplifiers at HF. Or did I misunderstand?
>>
>> 73, Pete N4ZR
>>
>That is true if you are talking about indirectly heated tubes with a separate
>cathode pin(s). The old glass tubes still need one.
>
>BTW, I see lots of ridiculously high bids for B&W FC-15's and FC-30's on
>E-Bay. Bear in mind that these do not cover 160 meters when you are bidding!
>
The 9uH fil. choke in the SB-220 works quite nicely on 160m. To cancel
the reactance of the choke, add approx 900pF to C2 in the 160m tuned
input.
cheers
--
FAQ on WWW: http://www.contesting.com/ampsfaq.html
Submissions: amps@contesting.com
Administrative requests: amps-REQUEST@contesting.com
Problems: owner-amps@contesting.com
Search: http://www.contesting.com/km9p/search.htm