locked Re: WSJT-X & FTdx-5000 #txaudio #Yaesu

Chuck Moore <wd4hxg@...>

I take my cue from two things for power output. One is the derating used by
the radio manufacturer for the radio when running AM vs SSB.  My rig is
rated for 200 Watts PEP SSB by Yaesu. For AM they specify 50 Watts. That
to me indicates that the safe upper end for high duty cycle SSB is going to
be about 50 Watts for my radio.  Also on the rig here there is an option to run
the finals in a very linear mode (Class A) as opposed to acceptable AB mode.
Running in the ultra linear mode as it is called results in the SSB output being
capped at 70 Watts PEP.  Since the extra 20 watts will be less than about 1.5
dB increase in power it hardly seems worth it to risk the health of the finals.
I will venture a guess that the repair bill for replacing the finals will be around
$450 - $600. Heap on that the shipping costs will be about $120.00 each way.
I will opt for the 4:1 derating and set the max threshold at 50 watts "for the rig"
when using digital modes.

Other than the occasional "Oops" of forgetting to reduce the power out, I cap
the RF out at 25 watts. I will generally use less power if PSKReporter and/or
HamSpots is returning reports of my Signal Strength being better than -5 dB.


Chuck WD4HXG

On August 3, 2021 at 10:13 PM, "Joe WB9SBD" <nss@...> wrote:

In a FTDX-5000MP,

How much power can we safely run in the high duty digital modes?

Like RTTY and the stuff in the WSJT-X magic box.

My old Kenwood TS-430S 100 watt rig, 100 watts OVERHEAT

Like 50 watts and the fan would never ever come on

75 watts was like a 50% duty cycle with the fan, so figured that was a
safe level.

My IC-7300, 100 Watts Period regardless of mode, the temp gauge may rise
1 bar at the most,
I have no idea what it takes to get that radio Hot!

But now this 200 Watt FTDX-5000MP

What power level ends up like the 7300, where the fan rarely comes on if
at all.

and what power level is like the 430S where the fan runs like half of
the time?


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