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Re: [IRCA] 1st NEW STN on 1400 Khz since 1982!!! WDNY, Dansville, NEW YORK
I think a fundamental stat for SDR is the ADC converter. Perseus is 14 bit.
QS1R and the new ELAD are 16 bit which provides more dynamic range.
My very basic research into ADC chips looks like they are improving, but
not that fast. Otherwise we'd be seeing radios based on 18 bit chips
with 140 msps sampling by now.
You can also have different noise figures on the ADC chips. So you want
one with the best signal/noise ratio.
There may be a tradeoff between the number of bits and bandwidth. Or at
least between bits, bandwidth and cost. So it gets pricy if you want to
cover 0-50 mhz (you need a sampling rate of twice the range) at 16
bits. So the Funcube sacrifices bandwidth in exchange for dyanmic range.
By contrast the very cheap dongles with wide bandwidth are only 8 bit
and suffer from very poor dynamic range.
I'm running a QS1R in Philadelphia, and I don't see any indication of
overload - including from the local powerhouse: a -5 dbm MW station. I
do think the station is overloading my Wellbrook 1530 s+ though (and I
get a large number of intermodulation products during the day, but
fortunately none at night).
I think good sdrs crush non-SDRs (so long as you have equal noise
conditions) - notably in unparalled selectivity (nearly brickwall
filters that can be sized to the nearest 1 hz) and resolution. So I
haven't used my Drake R8 in years. There is a learning curve, but it's
a ton of fun! I'd recommend that everyone buy a SDR for your main
desktop rig if you're spending more than say $200. For non-MW dx, it is
possible that some top end non-SDRs have better sensitivity - but for MW
- selectivity is so critical that SDRs are probably always the best choice.
The QS1R does have a couple quirks. The recording system is unfriendly
and I wish the two noise blankers worked better (by contrast the notch
is very strong). But in general it's an amazing radio.
Aaron
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