[1000mp] Re: MP Clicks

[Tom Rauch]

> I measured FT1000MpV keying wave shapes etc. with a spectrum analyzer.
> The rise time from 0->100% is about 2.7ms and decay time is about
> 1.3ms.

If the rise time is 2.7ms the closest possible sidebands in the 
waveform would be 370 Hz each side, the closest possible 
sideband upon key opening would be 770 Hz. 

So the CW signal must be at least 740 Hz wide on closure and 
1.54 kHz wide on key opening. That will be true no matter what 
speed CW you send.

We know it is NOT a filtered (either raised sine or gaussian) 
envelope rise and fall, the keying will have spectrum much wider 
than that. (The slope of the envelope rise and fall at any instant of 
time determines the bandwidth, and the amount of voltage change 
in the envelope at a slope determines the strength of the click.)

There is no doubt at all the MP MKV you looked at will produce 
significant keyclicks. These radios really should have 5ms rise and 
fall, with no steep slopes or sharp edges at any point in the 
waveform.The ideal waveform is gaussian.
73, Tom W8JI
W8JI@contesting.com