[Elecraft] [K2] Low TX Output on Higher Bands

[Don Wilhelm]

Steve,

When comparing the RF voltages between bands, I meant to say to use 30 
meters instead of 20 meters as stated.
The idea is to compare one band that is producing full output with 
another band that has the low output.

73,
Don W3FPR

On 11/8/2014 2:24 PM, Don Wilhelm wrote:
> Steve,
>
> I have found that behavior in K2s that have some problem with RFC3. 
> Make certain the leads are well stripped and tinned (you should see 
> some tinned wire above the board) and RFC3 is wound on the right core 
> - I have found a few where the builder used the black powdered iron 
> core instead of the ferrite core.
>
> The winding of T2 can reduce the power on higher bands, but not as 
> severe as you have, but check anyway to be sure T2 is wound as 
> indicated in the manual and spaced 1/16 to 1/8 inch above the board.
>
> You will likely have to do some modified transmit troubleshooting 
> using the test points indicated in the manual, but at a higher power 
> setting than 5 watts (I would recommend 10 watts setting). At each 
> test point, compare the RF voltage for 20 meters with that for 15 
> meters.  When you find the place where the RF voltage for 15 meters is 
> substantially less than that for 20 meters, you have identified the 
> output of the failing stage.
>
> 73,
> Don W3FPR
>
> On 11/8/2014 10:42 AM, Steve Kavanagh wrote:
>> As I proceed with checking the new-to-me (S/N 5133, bare-bones, no 
>> options) K2 out, I'm finding that the maximum transmit power output 
>> drops markedly as the frequency goes up.  If I set the power to 
>> maximum, I can get the following approximate powers (on CW):
>>
>> 80m: 15 W
>> 40m: 15 W
>> 30m: 15 W
>> 20m: 7 W
>> 17m: 4 W
>> 15m: 4 W
>> 12m: 1.5 W
>> 10m: 1.5 W
>>
>>
>