[Elecraft] dynamic range question was [FT817] ELECRAFT

[Jim Brown]

On 12/30/2011 4:51 AM, goldtr8 at charter.net wrote:
> Ok I admit I do not clearly understand this 30dB better dynamic range.

In very simple terms, it means that when a very strong signal is very 
close in frequency to another much weaker signal that you want to listen 
to, the KX3 can reject a signal that is 30dB stronger than the 817 can 
reject.  Putting it another way, on the 817, the stronger signal would 
take over, and you wouldn't hear the weaker one, but the KX3 would pull 
it through.

30dB is 1,000 times the power, which is equivalent to five S-units on a 
properly calibrated S-meter.  The S-meters on K3s are well calibrated if 
you've run through the procedures in the manual. The S-meters in most 
other radios are NOT well calibrated, and 30dB are often 8 or 9 
S-units.  That was the case on several "good" Kenwood and Yaesu rigs 
I've owned.

Most low cost rigs, especially those designed for mobile use (IC706, 
FT817, FT857, IC7000, and even the IC746) have this poor rejection of 
strong signals.  You can study ARRL Lab reviews of each rig to learn 
which rigs are better than others in this and many other ways.  If 
you're not an ARRL member, it's worth joining just to have access to 
this information!

73, Jim Brown K9YC