[Elecraft] KXB3080 Installed! Power a little low tho'

[Don Wilhelm]

Mike,

While a watt or so is not worth worrying about, you may want to check your
KXB3080 installation carefully, especially the new Low Pass Filter toroids.
My experience with 5 KXB3080 kits so far is that the power output will be
close to 4 watts on all bands with a 14 volt power supply - note that this
is with the resistor change and 18 turn L3 installed.  I have found that
some wattmeters will read a bit low on 80 meters, but replacing the 1N5711
diodes in the KXAT1 will bring the 80 meter power out indication close to
the actual power output.  You will need an RF Probe or 'scope connected
across a good 50 ohm dummy load (or a known accurate external wattmeter) to
determine whether your KXAT1 power calibration is correct.

73,
Don W3FPR

> -----Original Message-----
>
> I finished the installation of the 3080 option, and everything
> seems okay, but my power out seems to have dropped on all bands.
> Not by a lot, but I'm wondering if something is amiss.
> Here are the numbers, using the same 13.4v external supply before
> and after:
>
> Band      Before 3080      After 3080
> 80m       n/a                    3.1w
> 40m       3.9w                  2.7w
> 30m       4.2w                  3.9w
> 20m       3.8w                  2.8w
>
> looks like I've lost about a watt on 20 and 40.
>
> Current draw is good on all bands, about 65ma on 80 and 45 ma on
> the others.
>
> Is this worth worrying about?
>
> I read about the resistor mod, but that would raise output on all
> bands, maybe pushing 30 and 80 up above 4 watts, perhaps not a good idea.
>
> Is there an adjustment I missed for 20 and 40?
>
> Thanks,
> Mike N2HTT
> 4 band KX1 s/n 099
>