[Elecraft] K2 #5549 some questions/remarks

[Wyn Hughes]

A few months ago, after completing #5390, I ran a check on the cleanliness of the K2 transmitted CW signal on 28Mhz, using the spectrum scope in my IC-781 as a spectrum analyser. I could not detect any trace of spurii and the slopes of the received trace were sharp and smooth, with the scope set to 5Khz per division. Signal also sounded clean and pure to listen to.

I had to set up a high degree of 'attenuation' between the K2/dummy load and the IC-781 (with a wire antenna about 1 ft long), which I did by having the K2 running dits into the dummy load in one room of our apartment, and the IC-781 in another room some distance away. If you try this, take care to arrange enough proper attenuation, to avoid the risk of blowing the RF stage or switching diodes in your RX!

73 and Happy Holidays to all,

Wyn, VR2AX





In a message dated 25/12/06 10:53:49 GMT Standard Time,  
elecraft-request at mailman.qth.net writes:

1. when  looking at the transmitted signal using a spectrum analyser,
the signal didn't seem as clean as we liked it.  We didn't  have
time (it was the day before X-mas!) to really  start counting the
dB's, but on 30, 12 and 10 m we saw  some signals around the main
signal. Is there any  chance we can get these bands 'cleaner' by
further  tweaking the filters?



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Hi Jurgen,
 
Are you 100% sure that the spurii you are seeing are just not due to you  
overloading the input of the spectrum analyser?
 
This is a common cause of apparent excessive spurii!
 
Merry Christmas to all,
 
Bob, G3VVT