[Elecraft] K3: New (Jan 2009) ARRL review

[Joe Subich, W4TV]

> The second one was a mediocre performance of the 1.8 filter 
> (see table below). It had worse close IMD than the 2.7 
> filter, in some cases by 20db!

Careful reading of the review will reveal that the particular 
1.8 KHz filter was probably defective.  Elecraft run much 
higher signal levels in the first IF filter than other radios. 
That higher signal level can cause filter generated IMD if the 
crystals are not absolutely clean.  

Elecraft (and INRAD) are working on improved testing procedures 
to weed out those filters that are insufficient to handle the 
signals levels in the K3 (and divert them to use with Yaesu 
transceivers <G>). 

73, 

   ... Joe, W4TV 
 



> -----Original Message-----
> From: elecraft-bounces at mailman.qth.net 
> [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Ignacy
> Sent: Tuesday, November 25, 2008 4:20 PM
> To: elecraft at mailman.qth.net
> Subject: Re: [Elecraft] K3: New (Jan 2009) ARRL review
> 
> 
> 
> According to the review, the radio is nearly perfect. Very 
> strong performance nearly everywhere.
> 
> There were only two sets of numbers that could raise questions. 
> 
> The TX 3rd order IMD performance was not that good (29db) but 
> it was on the worst band.  Not sure the testing was before or 
> after the firmware changes to decrease TX IMD. W8JI praised 
> K3's low SSB IMD.  
> 
> The second one was a mediocre performance of the 1.8 filter 
> (see table below). It had worse close IMD than the 2.7 
> filter, in some cases by 20db! On the other hand, everyone in 
> this group praises the 1.8 filter so perhaps the filter is 
> still doing something useful. Also perhaps the latest 1.8 
> filters were improved.  
> 
> 
> Third Order Intermodulation Dynamic Range (dB) at MDS 
> (preamp off, 14 MHz) 	 
> Spacing (kHz)		 Roofing Filter (Hz) 		 
> above/below 
> 	2800 	       2700 	        1800   	500     	
> 400 	 
> 20 	104/104 	105/106 	101/98 	104/104 	
> 105/106	 
>  5 	105/103	 96/106	 90/84 	102/101 	106/105	 
>  2	 99/100	 90/89	 74/82	 90/90 	106/103	 
>  1	 94/81	 89/79	 72/81	 87/82	 99/99 	 
> 昀&#56547;
> 
> -- 
> View this message in context: 
> http://n2.nabble.com/K3%3A-New-%28Jan-2009%29-ARRL-review-tp15
77963p1578264.html
Sent from the Elecraft mailing list archive at Nabble.com.

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