When would the FreeDV wafeform be updated so that it don"t blow up a Solid State PA and it also can work in the lower side band mode ?

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When would the FreeDV wafeform be updated so that it don"t blow up a Solid State PA and it also can work in the lower side band mode ?
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pa0bie

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Posted 2 years ago

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George Molnar, KF2T, Elmer

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The DV mode shouldn't "blow up" anything when operated properly. The duty cycle is higher than SSB, so operators must adjust their equipment accordingly. 

As for LSB.. the use of USB for digital modes is by convention and shouldn't make a difference between QSO partners. 

Neither question really calls for a change to FreeDV or anything from Flex. Good luck & enjoy operating!
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Bob - G3WKW

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But not the convention for FreeDV which as a speech mode follows the convention for speech modes on the lower bands, as also do the SSTV enthusiasts. In U.K. The weekly RSGB news is being transmitted on 80m in LSB with nets before and after in LSB.
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pa0bie

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It is not the FreeDV mode that has blown up Solid State PA's , but the FRS FreeDV wafeform.  This is also confirmed by FRS 's  Matt Youngblood, KD5FGE , as a problem that needs a solution. In Europe we are working on 40 and 80 meters in LSB. For both reasons we are working with FreeDV.exe 1.1.  That means we have complicated situations with sound cards and assigned audio IN/OUT's.

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Lawrence Gray

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I use FreeDV with a solid state linear.  I have no issues at all, as long as I respect the amp's continuous carrier duty cycle.   I have held numerous QSO's with other stateside operators and not seen an issue with the amp.

Larry, W1IZZ
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Michael Coslo

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What is the specific issue that causes the amplifiers to "blow up"?
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pa0bie

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Hi Laary,

Normal FreeDV transmission:


FreeDV Wafeform:








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AA0KM

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Free DV flexradio ((wave form)  is all usb all bands.

And the downloaded software from the author of  freedv is 10meters-30meters  usb and 40meters

-160meters is lsb. The standard conventions of usb-lsb.

This was my finding a while back and the flexradio  (wave form) can not be changed from all usb to Lsb.

That's my understanding when I messed with it. So not compatible on 40 meters on down.

Understand this is not flexradio software.

If others use flexradio wave forms in usb  that's works.

 If others use the authors LSB modes that works but not crossed over on the side bands.

(Edited)
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pa0bie

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No reaction to the SSPA blown up problem so far. No solution to the LSB/USB issue so far.

In the meantime there are more modes in use within FreeDV then 1600.

There is 700B , 700C and 800XA.  The FreeDV wafeform starts to be oldbolish. 

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Ria - N2RJ, Elmer

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Is it possible to use just FreeDV with DAX? 
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pa0bie

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Yes You can use FreeDV with DAX as connection between FreeDV and SSDR.  But You have to use a headset on the PC instead of the microfoon and speakers from the Flex.  That give some restrictions , and also the PTT control is not ideal in that situation.


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Dave

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Yes but I can't get it the PPT to work at all.
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Ria - N2RJ, Elmer

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Ah, now I get it. That would be a problem then. 
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pa0bie

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You have to use the PTT button in FreeDV or the spacebar on the computer.

Perhaps this wil help.



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Dave

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OK Got it to transmit. Thanks for help!!!