>> By definition PEP can't be 100% duty cycle.
>
> REPLY:
Of course it can. You are confusing duty cycle with average power
output.
OK, make that 100% duty cycle at full output. Once you add a PEP
qualifier you're derating the tube ... or you're at least implicitly
saying this is not a constant carrier application. There is a *big*
difference between 100% duty cycle in FM or RTTY service and 100% duty
cycle in unprocessed SSB service.
Eimac's data sheet said 400 mA CW or PEP - in other words, non-constant
input/output. It also says 280 mA "two tone plate current" - in other
words, average over time. Eimac also rates the 3-500Z at 275 mA plate
current and 330 W plate dissipation for "carrier conditions" in plate
modulated class C service.
I'd suggest the "carrier conditions" rating is the most appropriate for
RTTY. With 275-280 mA at 2500V in AB2 one is still looking at a safe
limit of about 400W from a single 3-500.
73,
... Joe, W4TV
On 9/24/2012 11:12 PM, Bill, W6WRT wrote:
ORIGINAL MESSAGE:
On Mon, 24 Sep 2012 22:27:20 -0400, W4TV wrote:
By definition PEP can't be 100% duty cycle.
REPLY:
Of course it can. You are confusing duty cycle with average power output.
A two tone test signal with a certain PEP broadcast continuously is 100% duty
cycle. The same two tone broadcast in an equal on/off manner would be 50% duty
cycle. The PEP is the same but the duty cycle is different.
From Google definitions: "The cycle of operation of a machine or other device
that operates intermittently rather than continuously".
For example if you transmit SSB voice continuously you are doing SSB at 100%
duty cycle. If you transmit SSB voice for ten seconds, listen for ten seconds
and then repeat over and over, you are doing SSB at 50% duty cycle.
73, Bill W6WRT
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