Icom IC7300 output power. Does the percentage match?

Hi all,

as you can see in the Merlin Station page, I own an Icom IC7300 and it is my main HF transceiver.

Sometimes I need to make some tests with no power at the output, and of course the transceiver has the possibility to control the output power level as a percentage. Suprisingly in one of that tests I received an answer from an radio operator! So when 0% is set, there is any output power! But how much? And 5% may not QRP?

Some months ago I made a 200W (low duty cycle) dummy load in which I am able to measure the coaxial core so it was time of made use of it. I connected the dummy load to the Icom output and measured with the oscilloscope the output waveform, using CW modulation.

Finally I extracted the following table, which represents the figure at the right side:

  Reference Voltage (Vp) Power (W)  


Measured Output Power for each Configured Output Power

0 % 8.2 0.6724
5 % 17.2 2.96
10 % 28.8 8.3
20 % 38 14.44
30 % 47.6 22.66
40 % 56 31.36
50 % 65.5 42.9
60 % 70.5 49.7
70 % 79 62.41
80 % 85 72.25
90 % 90 81
100 % 96 92.16

Not that bad at all! Highly linear as it should be. Two observations are to be done: The first is that 100% does not measure 100W, but 92.16W that are not too bad taking into account that there was a cable + switch + cable + transition + microstrip (+ probe + scope) + load. The second one is what we told at the beggining, 0% giving output power??

May be easy to set a conditional sentence in the firmware to do not create any signal on the output DAC when 0% is configured, right?

Some photos of the measurements ;)

 

  

Be patient and methodic my friend

Hi all and a happy new technological year 2017!

The post of today is a totally different one of which I get used to publish, only one philosofical sentence:

"Usually there is not a good way to resolve a challenge in a short period. In that cases to be patient, methodical and ordered are valuable virtues to succeed"

Hardware and software (both firmware and high level software) are complex disciplines where projects usually cannot be successfully solved in a short period so be patient, methodical and ordered.

See you soon in another projects publications!

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