Carl wrote:
> That sounds like the old Radiokit 30A choke kit. It worked well down
> to 160M with a single 4-1000A
>
I think I built them just shortly before the kit came out. If memory
serves correctly I purchased a dozen of the rods, but I don't remember
where I purchased the enameled #10. There were a lot more sources back
in the 60's. <sigh>
73
Roger (K8RI)
> 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
>>>
>>> _______________________________________________
>>> Amps mailing list
>>> Amps@contesting.com
>>> http://lists.contesting.com/mailman/listinfo/amps
>>>
>>>
>> _______________________________________________
>> Amps mailing list
>> Amps@contesting.com
>> http://lists.contesting.com/mailman/listinfo/amps
>
>
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|