A year in HAM Radio

Hello all!

I had recently completed a year as radio operator under EA4GVA callsign and I am sharing my experience over this year. People who closely know me are aware of my interest in technology and they were not surprised that I started in this world, but many people asked me about my interest, remarking that radio is a 60's thing. At first I did not have too much arguments to explain all the interesting things around the simple purpose of communicating with others from one point to another. I can resume my best explanation in only one phrase.

"What is really important is not the only purpose of communicating with each other, but the way to reach it"

To talk about radio technology is to talk about electronics, low noise, signal processing, modulations, radiofrequency, antennas, propagation, human interfacing, instruments and measurement, equipment characterization, satellites, orbits, space weather... Does it seem strange why a high percentage of radio enthusiasts are engineers? Many of them are not recognized as it, but they simply are.

A HAM radio year in numbers:

  • I purchased 4 antennas
  • I designed and built successfully 5 antennas
  • I purchased 3 radios
  • I built 2 radios and a lot of accesories, from a remote switch to a radio-remote azimuth&elevation rotor, amplifiers, filters, dummy loads...
  • I obtained the DX World Award, confirming contacts with 100 different countries
  • I was awarded #3 Spain, #8 Europe, #13 World in the CQWW 2016 Rookie category contest
  • I made more than 2.000 contacts all over the world, including digital and satellite communications
  • I learned countless concepts about state of the art signal digitalization, Software Defined Radio, noise avoiding and mitigation...
  • I made a lot of new friends

I compile here different photos I made related with radio this year

Monitoring the Sun Weather


My antennas


The new friends


Designing new hardware


High Performance Equipment


Building new antennas



 The people


Building K5OOR amplifier 


Receiving NOAA satellite weather images 



Own designed satellite antennas and remote tracking system


Measuring RF Performance


In filed equipment testing



 Activating new geodesic vertex references


SDR playing and learning


 Making contacts all around the world



Thanks to all these HAM radio operators calling and answering our call, researching and sharing all their discoveries and knowledge, thanks to all that helped me everyday on this passion, this year has been only the first year, a great year, thanks.


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 ;)



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