Hi Guys
It's well know the ability to copy weak signal near strong carriers. I run a
QS1R using HDSDR all the time shearing the same RX antenna with my IC7800.
In the last 10 years only once I worked a new country on 160 listening on
the SDR that I was not able to copy using the IC7800. David summer was
operating "simplex" from 4U1ITU once on 160m. and the pile up with US and
European station was very "peculiar" on 1820.00. Everybody on the same
frequency. Yes the SDR is a better receiver but for practical reasons not
the more efficient radio to operate.
Just have a driver problem with windows and you will find yourself hours
trying to find why the IP address does not match the SDR anymore or other
silly software things that takes hours to fix.
I was not surprised to know from a good friend that some big contest
stations run DOS PC's!!
Here where the ADC overload gets complicated, when the ADC overload the
noise floor goes up for several seconds(or minutes), plus the pops. On low
bands all receiver antennas has different gain as you move up in frequency.
Like a Flag or beverage gain on 160m is low but the same antenna has 20 db
more gain on 10 MHz. Using the most common high pass filter to reduce AM BC
band bellow 1.8MHz infront a 20 db gain preamp, does not attenuate signals
from broadcast bands near 5 MHz, 7 MHz, 9 Mhz, 11 MHz, etc. Endeed the
signal can be 40 dBm stronger than it should be in a vertical without
preamp. If the preamp is not tuned or have a band pass filter after it ,the
problem of overload become a huge one, and you don't even know where the
overload is coming from. AM BC reduces power during the night but
propagation brings strong signal from HF broadcast at night, specially near
SR and SS. It is not all the same during the day time or during the night.
If you check the top contest results you can find a good reason why the top
stations are using only few Radios models.
Regards
JC
N4IS
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