Donald Chester wrote:
The plate dissipation of the 6146's is the key. Your carrier steady on
should not exceed the dissipation rating. This is about 50 watts if I
remember right which would give you 200 watts PEP. So your power suppl;y
should be capable of about 150 watts continuous and it will handle
the 200
watts on peaks. I would beef up the fan so that I had a good amount
of air
passing the glass of the 6146's to keep the seals cool.
In AM linear service, the carrier output should not exceed HALF the
total plate dissipation. A 6146 runs about 25 watts plate
dissipation, so with a pair of them, you should be able to run 25
watts out. With 100% modulation in the positive direction, that would
be 100 watts pep.
A properly functioning AM final capable of 100% modulation should run
about 33% carrier efficiency. That means that two-thirds of the input
power is dissipated in the plates of the final, and one third is
delivered as rf output.
When the carrier is modulated, the final actually becomes more
efficient, so the plate dissipation is reduced under modulated
conditions. The DC input should not vary, so that simply means that
some of the DC input that was being dissipated as heat is now being
converted to rf output in the form of sideband power.
Is that where sideband energy then is created and therefore exists as
long as there's a modulate AM carrier?
I wasn't in on the big discussion about this, a few months ago.
---
73 = Best Regards,
-Geoff/W5OMR
