OK the test is now complete and here is some more information:
At one KHz spacing, the dynamic range is as follows:
1.8 KHz filter 72 dB (expected as signal is right against filter-more on
this later)
1.0 KHz filter 85 dB (GREAT!)
500 Hz filter 72 dB (more on this later)
Tests with other filters were not conducted as the results would be
meaningless. By this I mean why test a 6 KHz roofing with a 1KHz spacing as
the interference would be two KHz inside the roofing filter!
OK more inft, the AGC threshold is .8mv. The phase noise at 10 KHz was 128
dBc. At 60 KHz spacing it was 117 dBc so something is funky with the
synthesizer here. The attenuators are on the money of 6, 12 and 18 dB. The
true preamp gain is between 12 and 13 dB. The sensitivity was 0.6 with the
preamp off and 0.25 with the preamp on. The noise floor in SSB is -121 eB
with preamp off. The noise floor in CW is -127 with preamp off. With
preamp on, it is -135 in either mode.
Again, an anomoly in the phase noise measurement occurs at 60 KHz spacing
where it is the worst.
OK rob indicates the s-meter is dead on at S9=50mv. With the preamp on, S9
is 12 mv.
The filter gain using 2.4 KHz as the reference of unity, the 20 KHz roofing
filter is 4 dB down, the 6 KHz filter is 1 dB higher, the 1.8 KHz filter is
1dB down, the 1 KHz filter is 1 dB down, the 500 Hz filter is 7dB hotter
(this is due to the filter amplifier which causes the noise floor to
increase and results in a degrading in dynamic range) and the 250 Hz filter
is 3dB hotter, again somewhat degrading the performance.
What the filter gain factors indicate is the amplfiier must be ahead of the
filters as the dynamic range degrades with some selections.
The actual filter bandwidths as measured are 2.4 KHz is 2347 at -6dB and
2744 at -60 dB. The 1.8 is 1773 and 2144. The 500 is 530 and 847.
Here is the bottom line according to Rob. The Orion is the BEST receiver he
has ever tested. It is some 20dB better tha any other up conversion radio
tested and some 10-12 dB better than a converted Drake R4C. How does that
strike you TenTec fans. Rob confirms what we all knew, the Orion is
essentially bullet proof when compared to other available commerical amateur
receivers.
That's it folks. Enjoy the data. This info should appear on Rob's web site
shortly. Visit www.sherweng.com for complete data and info.
73,
Charlie, W0YG..>>
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