Hi Eric,
I ran the comparison you requested on both the 3000 and the 5000A. Here
are the numbers (ADC-L, center of the observed range):
Radio 2.0.8 2.0.16
3000 -61.5 dBFS -61.5 dBFS
5000A -75.5 dBFS -78.5 dBFS
Since the 3000 showed no difference in ADC-L reading between the two
versions and the 5000A showed a 3 dB difference, I ran the test a 2nd
time to be sure. The results were the same. This is interesting
because both radio's S-Meters show a 2.9 dB difference in noise floor,
with v2.0.8 having the lower noise floor reading. What's particularly
interesting is that with v2.0.16 the 5000A shows a lower input level to
the ADC, but a higher noise floor.
As mentioned earlier in the thread, I'm running Windows 7 Ultimate
64-bit and the 5000A just returned from the factory with the V/U upgrade
installed. All tests were run at 50.192600 MHz, CW Mode, and 500 Hz
BW. The internal preamps were turned on, the noise blankers were turned
off and an HP 50 ohm calibration load was connected to the antenna
connector. For the 5000A, an external 26 dB, 0.5 dB noise figure preamp
was connected to RX1 In/Out and selected in the Antenna dialog box (the
gain was also entered as 26 dB in the same dialog box). When the
external preamp wasn't selected, the ADC-L reading dropped by 4.5 dB,
but there was still a 3 dB difference between v2.0.8 and v2.0.16.
You should be able to easily duplicate this test in your lab. If you
do, I'd be interested in knowing the results. I'll try the same
experiment on the 1500 as soon as possible. I haven't upgraded my
laptop to 2.0.16 yet, so I'll try the same test on it before and after
the upgrade.
73,
Clay W7CE
On 11/13/2010 7:59 AM, Eric Wachsmann wrote:
So we haven't changed the level calibration to my knowledge. This
means that there is likely some difference between the two versions
that causes this difference. I'm not sure what that would be though.
Another thing to check would be the ADC levels coming directly out of
the radio. You can do this on the RX Meter using the ADC_L and ADC_R
settings. Compare those in the 2 versions and let us know what you see.
Eric
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