[Elecraft] Best Digital Program for the K3?

[Julian, G4ILO]

Kok Chen wrote:
> 
> I had recently made some measurements of RTTY and PSK31 which shows  
> that sound card driven programs using DATA-A can put out a cleaner  
> transmitted signal than the K3's internal generators in the PSK-D and  
> FSK-D modes.
> 
> Unlike many other rigs, the K3 is very forgiving about the precise Mic  
> Gain/audio levels.
> 
> I'd found that with Mic Gain set to 6, audio levels anywhere between  
> 250 mV RMS and 350 mV RMS work equally well, with the RF output  
> tracking the PWR knob setting and not needing to readjust the audio  
> levels.  With many rigs, you need to adjust the RF output through the  
> amount of audio drive, just so you can keep the ALC turned off.
> 
> The measurements also show that the K3's transmit IMD is low enough  
> that AFSK RTTY waveshaping by software can help reduce the keying  
> sidebands when compared to a rig (K3 or otherwise) that uses FSK.
> 
> The bottom line (if you want to skip the nitty gritty details in the  
> above web page) is that the K3's PA at 50 watts average PSK31 power is  
> capable of better than -35 dBc IMD for close spaced carrier pairs.
> 
> By carefully tuning the audio drive, I can get -37 dBc, so I assume  
> the PA itself is good to at least that.  The -35 dBc number is  
> probably limited by something else in the chain.
> 
> 73
> Chen, W7AY
> 
> 

By 50 watts average PSK power do you mean PWR set to 50, or PWR set to 100
or whatever gives an average 50W out?

Don't know how accurate my off-air IMD Meter is compared to the measurements
you did, but I see -28dB IMD with PWR at 100W which I think is pretty
acceptable not that I personally would run PSK31 at that power setting.

The K3 seems just about idiot proof in digi modes. I often say the K3 is the
ideal radio for operating digital modes. If there is another rig that does
them even better I'd like to know what it is.

-----
Julian, G4ILO. K2 #392  K3 #222.
* G4ILO's Shack - http://www.g4ilo.com
* KComm - http://www.g4ilo.com/kcomm.html
* KTune - http://www.g4ilo.com/ktune.html

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