FreeDV power output

  • 2
  • Problem
  • Updated 3 years ago
  • Not a Problem
I was trying FreeDV on HF (20m and 15m) yesterday and the power output is very low regardless of the Power output that I select on SmartSDR.
Max power I get out of the radio is 25w.
I then checked AM and on 20m all I get is 16w.
On FM I get full 100w. Also get full power on DStar.

The voltage draw from the radio is also lower so it is like the software is using a governor.


I checked with a couple of 6xxx owners and they are also experiencing the same issue.

Thanks in advance for the help.
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EA4GLI - 8P9EH - Salvador

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Posted 3 years ago

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Jim Gilliam

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Remember on AM, for 100% modulation the peak power is 4 times the average power. The maximum average power you can expect on AM, therefore, is 25 Watts. 16 Watts seems very low. Were these power levels checked with a dummy load?


JIm, K6QE

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EA4GLI - 8P9EH - Salvador

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No dummy load. I measured with the digital meter on the Expert 1k.
I will check with dummy load.

What about on FreeDV? What power are you getting?
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Tim - W4TME, Customer Experience Manager

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Official Response
Your radio is not broken.  For proper operation of FreeDV, you drive your transmitter to an average power of about 20% of it's PEP power. You do this because there is a 8-12 dB peak-to-average power ratio in the FreeDV HF modem. Over-driving will reduce the received S/N so we limit the power output in software.
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EA4GLI - 8P9EH - Salvador

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Thank you Tim for the quick response!
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Tim - W4TME, Customer Experience Manager

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De nada, mi amigo.
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EA4GLI - 8P9EH - Salvador

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Hey Tim, did you already made the arrangements to bring my maestro in person to Barbados? We are awaiting here with some nice cold drinks! :)
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Tim - W4TME, Customer Experience Manager

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The offer is very tempting.  I could use a nice cold rum drink about now.
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EA4GLI - 8P9EH - Salvador

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What do you mean offer?? It is a formal invitation. Get your ass over here, housing and sustenance is taken care of!! ;)