wc6w@juno.com wrote:
>> -- "Phil Clements" <philc@texascellnet.com> wrote:
>>
> <snip>
>
>
>> Harris has been doing this for years in their amps. The RF->110,
>> (pair of 4CX1500B's) has a plate choke that is a very small ferrite
>> loaded unit that is clean from 1.8-30 mhz. This was the ideal fix
>> for adding WARC bands and 160 meters, but the amateur amp
>> manufacturers did not pick up on this.
>>
>> <snip>
>>
>>
>> (((73)))
>> Phil Clements, K5PC
>>
>
>
Would it be possible to have a look at the photos that you took of the
choke and parasitic suppressor arrangement that you posted on
www.pixhost.com/pixp/philk5pc/Platechoke.jpg but which are no longer
available?
> Hi Phil,
> If I recall correctly, that choke is listed on the schematic at
> 115uH.
>
> Employing the ferrite core should place the first (parallel)
> resonance suitably above 30 MHz.
>
> This appears to be a valid approach because of the low plate
> impedance (circa 1000 ohms). Though there will still be plenty of
> reactive current through that choke on the lowest bands.
>
> Still a compromise, albeit a less objectionable one than
> most "amateur" amps.
>
> I'm feeling just a bit of deja vu all over again. :-)
> To see why, start at this old link:
>
> http://lists.contesting.com/_amps/2000-03/msg00603.html
>
> 73 & Good evening,
> Marv WC6W
>
> http://wc6w.50webs.com/
>
>
Actually, it makes pretty good reading...all over again. ;-)
73,
--
Ken K4XL
k4xl@arrl.net
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