> I have not looked at waveforms on a scope, but this is what the 4391 > Power Analyst says. It would be interesting to look at some speech > patterns, but I have no idea what a good reference input would be or > how to accomplish that. The above is with my voice and saying "hello > test one two three" several times normally. :-)
Jack, W8OZA did an extensive review of K3 transmit audio processing using air traffic voice samples and his usual arsenal of automated test equipment in March 2009. http://cliftonlaboratories.com/elecraft_k3_speech_processing.htm The Telepost LP-100 wattmeter includes a peak to average function that shows the effects of compression/clipping. It is interesting to see the amount of "RF compression" introduced by traditional ALC - particularly when one understands the amount of distortion created. 73, ... Joe, W4TV On 8/20/2010 6:33 AM, Tom W8JI wrote: > **Without using enough compression** (CMP), a lack of SSB average > power level occurs because the ALC does not act the same in the SSB > mode as it does in other radios. This makes the audio sound thinner > or less powerful because there is less very short term (fast speed) > compression to level voice amplitude peaks and valleys. > > Using higher compression corrects this. > > For example using a sample and hold Bird 4391 power meter (it stores > the highest readings for later viewing), the highest (MAX) readings > are: > > FT1000MP MKV no processing, normal ALC, peak to average power ratio > 4.26:1 normal processing, normal ALC, peak to average ratio 3.85:1 > > K3 no comp, normal ALC, peak to average ratio 4.7 comp 20, normal > ALC, peak to average ratio 2.84 > > The 1000MP is almost the same with or without processor The K3 has a > drastic improvement > > I have not looked at waveforms on a scope, but this is what the 4391 > Power Analyst says. It would be interesting to look at some speech > patterns, but I have no idea what a good reference input would be or > how to accomplish that. The above is with my voice and saying "hello > test one two three" several times normally. :-) > > I must use the CMP at 20 or more or the audio sounds thin. No amount > of mic gain will correct this. > >> From 4391 Bird meter readings and my ear I think this K3 behavior >> is proper, > and the Yaesu actually is lacking because the ALC distorts the peak > to average ratio too much. In the K3, the ALC is not a processor. In > the Yaesu, the ALC acts as a processor. > > 73 Tom > > >>> After using mostly these rigs for SSB contesting in FY5KE or in >>> other places, we are still facing a lack of "dynamics", "punch", >>> "penetration", "power", whatever you call it. In other words, >>> when comparing this rig to our radios we previously used >>> (TS-850), with the same microphone (Heil HC-4 element) and the >>> same output RF power, the K3 is clearly way behind in term of >>> "average power" we can read on the Bird wattmeter wired on its >>> RF output. Even if observing the wattmeter needle is not a very >>> scientific measurement (we admit it), various comparative >>> reports on the air do confirm our feeling. > > ______________________________________________________________ > Elecraft mailing list Home: > http://mailman.qth.net/mailman/listinfo/elecraft Help: > http://mailman.qth.net/mmfaq.htm Post: > mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net Please help support this > email list: http://www.qsl.net/donate.html > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
