That sounds like the old Radiokit 30A choke kit. It worked well down to
160M with a single 4-1000A
Carl
KM1H
----- Original Message -----
From: "Roger" <sub1@rogerhalstead.com>
Cc: <amps@contesting.com>
Sent: Tuesday, December 23, 2008 12:15 AM
Subject: Re: [Amps] [rfamplifiers] which cathode choke?
>
>
> jeremy-ge wrote:
>> Id lean to the B&W, it gives you almost 500 Ohms Xl at 160 which is
>> OK.
>> Bypass the filament transformer end with .05 to .1 uF discaps. Ive no
>> idea what the MFJ's intended use is.
>>
> "Back in the old day", I wound a number of them on ferrite rods. I
> only
> remember the approximation of size but it seems as if the specs were
> in
> one of the handbooks. The rod was between 1/2 and 5/8" in diameter
> and
> about 6" long. The winding was close spaced, bifilar wound using #10
> enameled wire. One would handle a pair of 3-500's or 8877. I had a
> bunch
> of them but they and a lot of other stuff went when I did the first
> thorough clean out of "stuff I'll probably never use". I wish I had
> all
> that *stuff* back.
>
> At any rate, the chokes were easy to wind, worked well, cost little,
> and looked good. I say they worked well. They was 80 through 10. I
> never tried one on 160 and I don't remember the impedance.
>> The homebrew will work also but you will have to keep an eye on the
>> voltage drop.
>>
> I used one of the above on a pair of 813's with the voltage remaining
> well with in spec. Too bad it was so long ago that I don't remember
> any
> specifics.
>
> 73
>
> Roger (K8RI)
>> Carl
>> KM1H
>>
>> ----- Original Message -----
>> From: "Steve Flood" <kk7uv@bresnan.net>
>> To: <rfamplifiers@yahoogroups.com>; <amps@contesting.com>
>> Sent: Sunday, December 21, 2008 8:19 AM
>> Subject: [rfamplifiers] which cathode choke?
>>
>>
>> I have three different bifilar wound ferrite rod chokes.
>>
>> A homebrew choke measuring 127uH
>> A B&W FC-25A measuring 44uH.
>> An Ameritron/MFJ #10-15115-1 measuring 19uH.
>> The measurements were taken on one winding with an Elenco LCR meter.
>>
>> Which one would best for grounded-grid 813's operating 160m thru 20m?
>>
>> Thanks, Steve KK7UV
>>
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>>
>>
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