[Elecraft] Fw: XV144 and XV432 : How good are they ?

[Siu Johnny]

Hi Martin,

It is a very interesting and educational article in the webpage of DF9IC.

I do not have the extensive equipment to do the test.  However, I do use my 
ear to do a A, B, C comparison for the following under the same operation 
conditions:

IC910H, IC970H, XV144+IC7800

The combination of XV144+IC7800 outperform the other two in strong QRM 
condition in RX performance.  In Hong Kong, we live in high rise apartments 
in the urban areas.  Strong Mobile VHF stations are everywhere and always 
within 1-2 km for my antenna.

I believe the performance of the IF rig (i.e. IC7800 in this case) will 
dictate heavily the overall performance.  Anyway, it would be very help if 
you could educate us more on the issue of LO noise influence.

73

Johnny Siu VR2XMC
   ----- Original Message -----
   From: Martin DD4UKP
   To: elecraft at mailman.qth.net
   Sent: Thursday, October 05, 2006 5:34 PM
   Subject: [Elecraft] XV144 and XV432 : How good are they ?


   Hello,

   I was looking for informations to extend my Elecraft line by purchasing
   the XV144 Transverter for Contest operations. I found the following
   homepage from DF9IC : http://www.df9ic.de/tech/trxtest/trxtest.html

   The K2/XV144 and even K2/TR-144H by DB6NT results seems to be terrible :

   "The Elecraft K2 also has a low IF design using conventional VCOs which
   should result in a good LO noise suppression but does not do so well. We
   had two radios on the bench, one from 1999 (DJ5IR) and one from 2004
   (DJ0QZ). This last one was tested on 14 MHz and showed better results
   than the older one on 28 MHz. You may compare the ARRL test results of
   the LO noise that Elecraft publishes on their own website and which is
   closely within our blocking test result (our measured -95 dB RX blocking
   in 20 kHz offset is equivalent to -129 dBc/Hz LO noise). The high level
   of TX noise shows that there seem to be design flaws choosing too low
   signal levels internally. The AGC threshold is ridiculously high
   (subjective impression). I also do not understand why it uses low
   quality ladder crystal filters instead of a filter from monolithic duals
   like other radios does. Overall it was the worst HF radio in the test
   (OK, a 144 MHz IC910H is still worse...)."

   Am I just expecting to much from this Transverter or is the K2 as a IF
   for 144 MHz operations not the right rig ?

   I'll be happy to read about your experience with the XV144 in heavy 2m
   contest operations.

   Sincerely

   Martin Rath
   DD4UKP / F4UKP
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