There is no RF current (or very little) to speak of at the BASE (cold RF
end) of the plate choke.
73
Jim W7RY
----- Original Message -----
From: "Russ Williams" <hrd998cc@yahoo.com>
To: "Steve Flood" <kk7uv@bresnan.net>; <amps@contesting.com>; "Jim W7RY"
<w7ry@arrl.net>
Sent: Sunday, January 11, 2009 9:15 PM
Subject: Re: [Amps] plate bypass caps
> But will they handle the RF current?
>
>
> --- On Sun, 1/11/09, Jim W7RY <w7ry@arrl.net> wrote:
>
>> From: Jim W7RY <w7ry@arrl.net>
>> Subject: Re: [Amps] plate bypass caps
>> To: "Steve Flood" <kk7uv@bresnan.net>, amps@contesting.com
>> Date: Sunday, January 11, 2009, 8:44 PM
>> Yup! Here are some. They are 5000 PF but just put two of
>> them in parallel
>> for .01 at 4KV. Steve said 2700 volts. So these should work
>> fine? Ebay Item
>> number 260288197318
>>
>> 73
>> Jim W7RY
>>
>> ----- Original Message -----
>> From: "Carl" <km1h@jeremy.mv.com>
>> To: "Steve Flood" <kk7uv@bresnan.net>;
>> <amps@contesting.com>;
>> <rfamplifiers@yahoogroups.com>
>> Sent: Sunday, January 11, 2009 6:50 PM
>> Subject: Re: [Amps] plate bypass caps
>>
>>
>> > Im using CD .01 6KV that I got off an Ebay surplus
>> components seller.
>> > Mylar type and USA made, about $1 each in 20 quantity.
>> >
>> > It has been my experience that 160M performance
>> improves with the .01
>> > which I parallel with the existing .001
>> >
>> > Carl
>> > KM1H
>> >
>> > ----- Original Message -----
>> > From: "Steve Flood"
>> <kk7uv@bresnan.net>
>> > To: <amps@contesting.com>;
>> <rfamplifiers@yahoogroups.com>
>> > Sent: Sunday, January 11, 2009 8:38 PM
>> > Subject: [Amps] plate bypass caps
>> >
>> >
>> >>I have an Ameritron plate choke mounted in my amp
>> project. It is
>> >>225uH. With 2700 plate volts, this is 2544 ohms at
>> 1.8 MHz and thus
>> >>1.06 amps. I am now assuming the plate bypass
>> capacitor at the base of
>> >>the choke must be very low reactance on 1.8 Mhz
>> which tells me .01 or
>> >>.02 uF at maybe 5kv rating. Am I thinking about
>> this correctly? If
>> >>so, such capacitors seem quite rare - the usual
>> internet sources only
>> >>carry .001 or .002 which would seem ineffective at
>> bypassing at 1.8
>> >>MHz. Yet, there are many 160m amp designs that use
>> .001 for bypass.
>> >>Perhaps they are using much much larger plate
>> chokes?
>> >>
>> >> Steve, KK7UV
>> >> _______________________________________________
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>> >> Amps@contesting.com
>> >> http://lists.contesting.com/mailman/listinfo/amps
>> >>
>> >
>> > _______________________________________________
>> > Amps mailing list
>> > Amps@contesting.com
>> > http://lists.contesting.com/mailman/listinfo/amps
>> >
>>
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>
>
>
>
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