>-- "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
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/
*
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