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Re: [IRCA] WC Nov 5 snapshot - SDR shoot-out
- Subject: Re: [IRCA] WC Nov 5 snapshot - SDR shoot-out
- From: Aaron Kreider <aaron@xxxxxxxxxxxxxxxxxx>
- Date: Sun, 6 Nov 2016 01:14:57 -0500
- Delivered-to: archive@xxxxxxxxxxxxxxxxxxxx
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Drake R8s are pretty cheap these days. I'm selling mine for $450 (plus
shipping) on Ebay. Original owner. Refurbished by the Drake R8
manufacturer several years ago, and rarely used since
http://www.ebay.com/itm/Drake-R8-Shortwave-Receiver-/291918828655
...
Selectivity: The good SDRs with 14-16 bit AD converters (Elad 2,
Perseus, the most recent Winradios, QS1R) crush traditional (non-DSP)
radios (even the $10k models) in terms of selectivity both in terms of
the shape factor (I think we get close to 1.1?) and number of filters
(unlimited). I'm not sure about ultimate rejection. You can also get
great selectivity with the cheap portable DSP radios (though they have
other problems).
Stability - varies a lot. I think if you want extreme stability you
need an external reference. Now where SDRs have the advantage is that
you can apply a general offset to fix your accuracy. You can use a time
signal or other known stable signal to get your accuracy as high as
possible. So it's cheap accuracy. I can measure carriers with accuracy
of plus or minus 0.1 hz on the QS1R on MW (or plus or minus 0.2 hz if
the station is coming from 2000+ miles) which is useful if you want to
null or maximize a station in a pile of others. I can also receive
frequencies with 1 hz resolution (the Drake R8 was 10 hz accuracy).
Sensitivity: I think is a tie. In both cases the radios have more than
enough sensitivity when provided with a half-decent antenna (and in
low-noise areas you want a good/long antenna anyways).
Software: A SDR can be dependent upon good software from the
manufacturer. The one advantage you have over non-SDRs is that there
are some software like SDR Console V3 (which I think is the best) that
handle most of the popular radios (though unfortunately not the QS1R,
but I can use the HDSDR). By contrast the Drake R8 manufacturers came
out with a single update (on EPROM). In general you can expect that
your radio will improve over time due to new software, whereas with
traditional radios it is less likely. The custom QS1R software is very
good - though they are unfortunately never going to improve their
recording function due to the company having limited resources. I also
have an SDRPlay and their custom software is frankly extremely quirky
and some of the worst User Interface design I've seen. The Drake R8
also suffers from a bad user interface which was only partially fixed by
the second EPROM.
Dynamic Range: my QS1R seems to have about equal dynamic range with the
Drake R8. It might be better, as I never used the R8 with an amplified
antenna nor living 1 mile from an AM station.
Frequency coverage: SDRs typically have wider coverage. The QS1R goes
from about 0 khz to 65 mhz and can be modded to receive up to 200 mhz or
so (I haven't tried it).
Modes: SDRs excel at having more modes, including digital decoding. For
instance, the QS1R (and others) can decode an entire band worth of CW
simultaneously.
Notches: I think I can create ten customizable notches (set the
frequency and width) as well as an automated notch. That said, I
normally only need one notch.
Noise reduction: I'm still hoping that SDRs will improve upon their
noise reduction and blanking techniques. I never use "Noise Reduction"
and Noise Blanking is useful, but could be a lot better. I think there
are ways to identify noise and cancel it out that haven't been tried.
For instance, I think you should be able to cancel out lightning noise
bursts or the noise from switching power supplies (maybe I'm a
dreamer!). In the future, I'm hopeful that software based antenna and
receiver phasing will be more common.
Now I had a great time with my Drake R8, spending thousands of hours
listening to radio stations - especially in the 1990s when the dials
were full of radio stations, but now I've got limited space and am happy
to go with an SDR.
Aaron
--
High resolution map of race and income --> JusticeMap.org
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