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 -- View this message in context: http://n2.nabble.com/Best-Digital-Program-for-the-K3-tp4534355p4537857.html Sent from the [K3] mailing list archive at Nabble.com. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
