KX3 running warm even at very low power out

[Mike Parkes]

I have been experimenting with WSPR mode at 2-10 milliwatts of power out as
measured by the WM-2 wattmeter. I notice that the back of the KX3 heat
sinks are still fairly warm to the touch at such low power. It surprises me
that the finals would still get that warm at this level of power out. Is
that normal? I don't want to damage the radio tryin mg to xmt very low
power! :)... I have nothing to compare to except it feels at least as warm
as it did at 1 or 2 watts out. (I am using the power level output from
WSJT-X to set the power out to levels lower than what the KX3 can show
which is limited to 100 mW.)
Mike AB7RU
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[rich hurd WC3T]

The only time I've ever gotten a HI TEMP warning was running WSPR at about
0.1 watt.   Go figure.

On Thu, Dec 6, 2018 at 3:50 PM Mike Parkes <[hidden email]> wrote:

> I have been experimenting with WSPR mode at 2-10 milliwatts of power out as
> measured by the WM-2 wattmeter. I notice that the back of the KX3 heat
> sinks are still fairly warm to the touch at such low power. It surprises me
> that the finals would still get that warm at this level of power out. Is
> that normal? I don't want to damage the radio tryin mg to xmt very low
> power! :)... I have nothing to compare to except it feels at least as warm
> as it did at 1 or 2 watts out. (I am using the power level output from
> WSJT-X to set the power out to levels lower than what the KX3 can show
> which is limited to 100 mW.)
> Mike AB7RU
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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> Post: mailto:[hidden email]
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--
72,
Rich Hurd / WC3T / DMR: 3142737
Northampton County RACES, EPA-ARRL Public Information Officer for Scouting
Latitude: 40.761621 Longitude: -75.288988  (40°45.68' N 75°17.33' W) Grid:
*FN20is*
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[Brian Hunt]

During transmit your PA current will increase even with no power out due
to biasing of the final PA devices.  On my KX2 current draw goes from
135 mA (RX) to 500 mA (TX) just by hitting the XMIT button but with no
key down.  Over the 2 minute TX cycle of WSPR that will heat up the heat
sink a bit.  But that's normal.  HTH

72,
Brian, K0DTJ

On 12/6/2018 12:50, Mike Parkes wrote:

> I have been experimenting with WSPR mode at 2-10 milliwatts of power out as
> measured by the WM-2 wattmeter. I notice that the back of the KX3 heat
> sinks are still fairly warm to the touch at such low power. It surprises me
> that the finals would still get that warm at this level of power out. Is
> that normal? I don't want to damage the radio tryin mg to xmt very low
> power! :)... I have nothing to compare to except it feels at least as warm
> as it did at 1 or 2 watts out. (I am using the power level output from
> WSJT-X to set the power out to levels lower than what the KX3 can show
> which is limited to 100 mW.)
> Mike AB7RU
>

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