On Jan 6, 2007, at 7:39 AM, FRANCIS CARCIA wrote:
Thanks Rick,
ur welcome
Well I think the 4CX5000 will do 11 KW max .
so that puts your numbers 8/11 max or about 75% of max to stay clean. I suppose a good high plate supply with enough screen voltage to provide enough gain.
An 8170 or 8171 will do 5k more on SSB with 1500v screen and 9kV anode. The key to maximal output is maximal screen-V. Increasing the screen potential from 1250v to 1500v results in c. 30% more output.
I'm actually playing with an old Viking 2 CDC modulator that uses 807s. Crazy flash back to youth. Rig is so I can get on AM from summer home. Small lot near the beach not really suited for QRO.....at least during waking hours. gfz
R L Measures <r@...> wrote:
On Jan 5, 2007, at 6:22 PM, FRANCIS CARCIA wrote:
So Rick,
Do I assume you never want to drive the grid 1 positive
Correct. AB1 means the grid is never driven into positive region.
Sure, it sounds strange to say the maximum grid potential is 0 volts,
but it's true.
or let the plate voltage swing below the screen for cleanest output?
For a pentode, the minimum anode potential can swing slightly below
the screen potential with no problem, but with a tetrode, the screen
current - as well as total IMD - goes through the roof when the anode
potential dips below the screen V. Thus for AB1 SSB, use an
abundance of anode V. plus the max screen V.
Any feel for the output power limit for say a 4CX3000A holding that
operating condition? gfz
Plywood Box #2 would do c. 8kpep out in AB1 / SSB with 1kV on the
screen.
...
R. L. Measures, AG6K, 805.386.3734
r@..., rlm@..., www.somis.org
R. L. Measures, AG6K, 805.386.3734
r@..., rlm@..., www.somis.org
