[Elecraft] K2/100: PSK31 at 50 watts Screen Shot

[Bill Strong]

Julian, G4ILO wrote:
> 
> 
> 
> Bill Strong wrote:
>> 
>> http://picasaweb.google.com/billstrong50/DigitalMaster780#
>> 
>> This is a screen shot by KG3BOZ of my K2/100 running 50 watts on 40M
>> PSK31. It shows IMD -23. This is a distance of about 1400 miles from
>> Mississippi to Maryland at about 0100 UTC. My antenna is a Cobra
>> Ultralite Senior up 20 feet. I tune it with the KAT100 and a big DXE
>> balun.
>> 
>> I usually run 20 or 30 watts but I wanted to see if I could run 50 watts
>> mainly for use on 80M. If I blow a small fan on the heat sink the
>> internal fan rarely comes on at 50 watts during converstaional PSK31.
>> 
>> I use the Data Mode with the ALC set to light one bar. I transmit in the
>> middle of the bandpass of the 2.2K SSB filter at 1000Hz.
>> 
> I would think an IMD of -23dB is barely acceptable. (My KK7UQ IMD meter
> defines "good" as better than -23dB.) However IMD measurements received
> off-air by software are not reliable and often show poorer readings than
> actual because the SNR is not good enough. Looking at the trace on your
> screenshot I would have said your IMD was better than -23dB.
> 

Thanks Julian for the observation. I did not know about the inaccuracy
although I did suspect over the air measurement might be different than in
the shack. The best IMD I have seen on DM780 is about -27 with a super
strong signal. I posted this because I thought it might be of interest to a
newby like myself. It took me a while reading on the internet to begin to
get a grasp of PSK31. Much of the best information has been on this forum.
73's
Bill 

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