I wrote:
>Threshold Orion Noise Floor (unadjusted for 3 dB MDS definition):
21.28 138
31.91 138
47.87 138
63.83 138
95.74 139
191.48 139
>To adjust for MDS = 3 dB S+N / N, 3 dB should be subtracted from the above
results. This would yield about -135 dB MDS for 7 MHz which agrees nicely
with ARRL's measurement of -135.4 at 7.020 MHz.
While I had my XG-1 out, I decided to measure my K2 also. Using K2's
700 Hz Xfil setting, I measured the K2 Noise Floor at -141 dBm. Adjusting
for the fact that K2's "700 Hz" filter is actually 340 Hz, I must subtract
the difference in Noise Bandwidth to get the equivalent measurement for
a 500 Hz BW (i.e. Orion). 10 log (340/500) = -1.7 dB, so the K2's equivalent
500 Hz Noise Floor would be about -139 dBm. Then adjusting for 3 dB S+N / N,
I calculate the K2 at -136 dBm versus -135 dBm for Orion, which is close
to ARRL's measurement of -136 dBm for both (14 MHz, 500 Hz BW, Preamp On):
http://www.elecraft.com/K2_perf.htm#5%20kHz%20numbers
73, Bill W4ZV
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