[Elecraft] K2/100 Flat topping on 30m?

[kc4kgu@ENTERZONE.NET]

On Wed, 30 Oct 2002, Larry - WA2DGD wrote:

> Hi John,
> 
> I'm interested in knowing how you are sampling the RF from the K2. Did you
> build a "tap" with an attenuator? Please share your circuit with me.
> Also, where are you getting the audio from. Before or after the volume
> control.
> 
> Thanks,
> 73
> Larry
> WA2DGD


I've had several people ask me how I'm driving the scope so, here it is
for all to see:

AF monitoring is only available when I'm using my outboard audio
chain.  The 0db signal from my mixer goes to the LINE LEVEL audio IN port
of a RigBlaster Pro.  I am tapping that audio via the LINE LEVEL audio OUT
port of the RigBlaster Pro and feeding it into the oscilloscope to drive
the bottom trace seen in the images I posted.  The MIC output of the
RigBlaster Pro then drives the K2 (or TS-2000, depending on which radio
I'm using the outboard audio chain with).

To "tap" the RF and drive the upper trace of the oscilloscope, I took a
piece of coax, soldered a BNC on one end to connect to the oscilloscope
input and on the other end, I stripped the braid back about 3 inches or
so, took the inner conductor (with the insulation still on it) and made
three loops then soldered it to the shield.  The Coax going from the K2
runs THROUGH this "loop".

I'm sure there is probably a "better" way to do this but, it seems to work
OK for me.  It is not as sensative at lower frequencies as it is on the
higher bands though.

73 de John - KC4KGU
K2/100 #2490