[Elecraft] Re: K2 Output power

[Wayne Burdick]

Isaac, 

Your external meter may not be accurate in the 10-watt range. Most of them are
calibrated at 50 or 100 watts and some tend to be inaccurate at the low end due
to excessive drop across the detector diodes.

But if you feel that you should be able to get power up further, send e-mail to
Gary (support@elecraft.com). He'll send you a full list of suggestions.

On 10 and 12 meters, check the "Po28" secondary menu entry, which may be
artficially limiting max power on these bands. That's its function. Po28 is
further described in the "K2 Rev 2 Firmware Manual" (and now in the latest K2
manual, revision D).

If you see a drop of as much as 0.9V on TX, it's probably a combination of about
0.5 V across the reverse-polarity diode (SB530) and the rest across your power
supply cable leads (half on the hot and half on the ground lead). This is
perfectly normal, and is not the limiting factor on power output if your supply
is putting out 13.6 V nominally. But you can recover most of this drop, if you
want, by doing two things:

1. Use a 95SQ015 diode rather an SB530 (supplied with our "K2ATOBKT" mod kit).

2. Use much heavier power supply wires.

As for your 300 mA receive current drain, you can of course reduce this when
necessary to about 150-180 mA by following the suggestions in the manual (see
the "Advanced Operating Features" section).

73,
Wayne
N6KR



TL wrote:
> 
> Hello all K2 users
> Just finished an extensive set of MODS to # 1574 and very happy with results
> (AF Pot, all filter Xtals change, ALC, Sidetone, Agc).
> After carefully adjusting my K2 "by the book" I find  my output power /
> current (dummy load) to be as follows:
> band    power           current
> 80       10.3w            2.1A
> 40       10.0w            2.2A
> 20        9 w               2.3A
> 15        8.8w             2.4A
> 10        8 w               2.6A
> 
> My RX voltage / current reading is  13.6v 0.30 A, on a K2 equipped with
> KIO2, KSB2,KNB2
> K160M and a small AMP keying interface.
> 
> I have noticed an 0.6 V- 0.9 V  drop on TX when level is set to 6-10w ( band
> dependant.).
> These power reading , are from my external analog power meter and are always
> lower by
> 0.2w to 1.5w from K2's  internal power meter indication. (worst case 28
> Mhz).