[Elecraft] K3 - Performance on 6M?

[Joe Subich, W4TV]

> The Elecraft external preamp with 0.7 dB noise figure and 18 
> dB gain helps a lot:
> 
> K3 with PR6 external preamp
> 
> 	preamp on 	0.9 dB
> 
> And the preamp is pretty robust to strong signals.
> 

Is this calculated with both preamplifiers on (cascaded) or 
with the PR-6 only? 

73, 

   ... Joe, W4TV 
 



> -----Original Message-----
> From: elecraft-bounces at mailman.qth.net 
> [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of James Duffey
> Sent: Friday, April 02, 2010 5:54 PM
> To: elecraft at mailman.qth.net
> Cc: James Duffey
> Subject: Re: [Elecraft] K3 - Performance on 6M?
> 
> 
> No need to speculate on the 6M K3 NF, we can calculate it. 
> Computing the K3 noise figure from the minimum discernable 
> signal (MDS) gives
> 
> preamp off 	 18 dB (K3/100 test) to 20 dB (K3/10 test)
> 
> preamp on	 12 dB (Same in both tests)
> 
> compare these to other 6M rigs out there:
> 
> IC-551D
> 	preamp on	6dB 
> 
> 	internal rf amplifier not switchable
> 
> DEM 50-28CK transverter with TS-850S IF
> 
> 	preamp on 	2.1 dB
> 
> 
> FT736R
> 	preamp on 	5.7 dB
> 
> TS2000
> 
> 	preamp off 	 20 dB 
> 
> 	preamp on	 5 dB 
> 
> IC756 Pro III
> 
> 	preamp off 	 15 dB 
> 
> 	preamp on	 5 dB 
> 
> FT2000
> 	preamp off 	 26 dB 
> 
> 	preamp on	 8 dB 
> 
> So the K3 is pretty deaf on 6M and yes, that is a result of 
> the design emphasis on HF strong signal handling capability. 
> The Elecraft external preamp with 0.7 dB noise figure and 18 
> dB gain helps a lot:
> 
> K3 with PR6 external preamp
> 
> 	preamp on 	0.9 dB
> 
> And the preamp is pretty robust to strong signals.
> 
> For terrestrial signals in a quiet rural area, a noise figure 
> of 4dB or less is probably adequate. For EME, you want less. 
> For urban and suburban areas, the noise is often high and 
> many people, unfortunately won't notice the inadequacy of the 
> K3's front end on 6M. - Duffey
> --
> James Duffey KK6MC
> DM65tc
> Cedar Crest NM
> 
> 
> 
> 
> 
> 
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