[Elecraft] KAT2 Bridge null adjustment

[Don Wilhelm]

Ed,

I would also recommend doing the power calibration on 40 meters - it is 
a good compromise.  There \is some variation in the response of the 
diodes with respect to frequency, and also, if you are using an 
oscilloscope to measure the RF voltage, the bandwidth of the 'scope can 
cause some "confusion" - if your 'scope (and probe) is rated at 35 MHz, 
the vertical response will be down  3 dB at 35 MHz.  The use of a 'scope 
rated at 35 MHz can be used for RF voltage measurements at 7 MHz, but 
using it at 14 MHz, expect that the RF voltage shown by the scope will 
be less than the actual RF voltage.  Do not even think of using a hunk 
of coax attached to the 'scope to measure RF voltages with any accuracy 
- a 10X probe is mandatory to keep the 'scope from loading the device to 
be measured (in this case, the transmitter output).

73,
Don W3FPR

On 8/13/2011 7:53 PM, EMD wrote:
> Thanks Don,
>
> I will give that a try.  Should I use the RF probe that I made or just use
> the DMM probes?
>
> 73,
> Ed ke7hga
>
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