Topband: rigs for top band

[Bill Tippett]

N6TR:
 >The specs have not been published yet

         Actually they are published.  See:
http://www.elecraft.com/K3/K3_specs.htm

Although these only go to 5 kHz spacings,
the IMD and BDR numbers are indicative of
very high performance (phase noise not
yet published but should be very good):

RECEIVERS (Main and Sub)

Sensitivity: -136 dBm or better (typical), 500Hz b/w.

IMD3 Dynamic Range (400 Hz 8-pole filter)**: >100 dB at 5, 10, and 20 
kHz spacing

Blocking Dynamic Range (400 Hz 8-pole filter): >140 dB at 5, 10, and 
20 kHz spacing

Image Rejection: > 70 dB

IF Rejection: > 70 dB

S-Meter: Nominally S9 = 50 uV, preamp on; user adjustable.

Noise Blanker: Adjustable, multi-threshold, multi-width hardware 
blanker plus DSP blanker.

8-Band RX graphic EQ: +/- 16 dB/octave.

IF Shift/Width & Lo/High Cut adjustable filtering.

         You are correct that the Achilles heel of SDR
rigs is poor BDR performance.  If I recall, I believe the
SDR-1000 is in the order of 110 dB and the SDR-5000
may be around 120 dB (but there is actually no BDR
published spec on Flex'sr website.  BDR is important if
you have very strong transmitters nearby, such as in
multi-TX contest setups, Field Day or a very close
neighbor.

                         73,  Bill  W4ZV

P.S.  I configured my K3/100 including high performance
Sub RX, KXV3 (for external RX ANT input) and two 500 Hz
roofing filters for $2525 unassembled ($2825 assembled).