[Elecraft] K2 S/N 4787 First QSO

[G3VVT at aol.com]

In a message dated 16/03/05 22:48:02 GMT Standard Time, g4bjm at hotmail.com  
writes:

The K2's  I've tested fall down on LO 
phase noise performance.  Also note that  the K2 measurements on the Sherwood 
web site state that the receiver  performance is limited by phase noise.  I 
agree the RX works very  well, but I've attracted comments on the air (when 
running QRO) re  transmitted phase noise.


------------------------------------------------
 
I wonder if there is an obsession with numbers. To place the matter in  
perspective, the Sherwood Engineering web site does list the K2 which  is serial 
#3170 or about 2 years old? as being the 7th from the  top of all the ham radio 
receivers tested. The aspect of the  effects of phase noise being only one of 
many parameters that determine the  final result.
 
I would presume that to measure phase noise needs the resources of a well  
equipped professional lab. Whilst personally I am well equipped to carry out  
servicing of radios from HF through to UHF, cannot even really scratch the  
surface in terms of measuring phase noise. The professional communications  
systems servicing organisation I worked for despite being well equipped for  testing 
from HF though to microwave in the field had little that could be used  
seriously for testing phase noise except for probably some rather expensive HP  
spectrum analysers that were issued only recently to maintain a new 8GHz digital  
microwave system.
 
Before slagging the K2 one should take more seriously what it represents in  
terms of outlay, costing only a fraction of cheapest HF transceivers available 
 on the market. Admittedly you have to build it yourself, but still the  
performance of the K2 as what it was primarily designed for, a QRP CW  transceiver 
takes a heck of a lot of beating. There are shortcoming that occur  with the 
additional added components, though even these have been mitigated by  later 
modifications.
 
Do the persons reporting phase noise on K2 TX really know what they are  
talking about or just pushing out some mumbo jumbo that just happens to be the  
popular quotation of the day? To be frank most hams including myself  would 
probably not be be aware what phase noise is even if it jumped out and bit  them.
 
Bob, G3VVT
K2 #4168