Thanks Mike for explaining the context! I've done extensive weak signal
listening with an Apache Labs ANAN-100D (DDC SDR running OpenHPSDR
software/firmware) compared with a slew of highly regarded analog and
hybrid (dsp i.f.) receivers and if anything, the SDR betters them
slightly. My subjective impression is also that the DDC SDR sounds
slightly "cleaner" with slightly less "grundge".
And a response to one of Mark's comments - the filter shaping in the DDC
SDR is not normally brickwall shaped. The shape is configurable by
selecting dsp buffer size and there's a trade-off between receive latency
and filter slope - see http://anan-100d.wikidot.com/100d-buffer for
passband plots - my dsp filter slopes are on par with xtal filter slopes.
73, Barry N1EU
On Tue, Oct 13, 2015 at 1:35 AM, Mike Waters <mikewate@gmail.com> wrote:
> Hi Barry,
>
> Thanks for your input. Yes, I believe we included direct sampling digital
> receivers (SDR) versus superhet receivers.
>
> The post I made here today is not complete; rather that re-post
> everything, I included a link to the early August discussion, which
> explained in detail what I meant. This is what I asked:
>
> "I'd like to know whether it's ever been established that some very
> talented
> hams can out-hear the best SDRs and/or DSP available. Can a skilled
> ear-brain combo (such as some highly-skilled and talented 160 meter
> contesters) beat state-of-the art digital signal processing when it comes
> to copying the very weakest of signals buried in the noise?
>
> "I always thought Linrad was the best DSP software, though I never got it
> working right here (older sound card issues in Xubuntu).
>
> "I asked the following question at
>
> http://www.eham.net/ehamforum/smf/index.php?topic=104388.msg861047#msg861047
> : "Are there any people who can hear weak signals with a good analog
> receiver, who --if they could instantly switch their antenna and headphones
> from the analog RX over to the best SDR made today-- simply couldn't hear
> any better with today's best SDRs and/or DSP software?"
>
> "There's been a few opinions, but how about multiple valid tests?"
>
> There were a number of replies, both on the Linrad and the Topband
> reflectors. Sounds like you don't agree with most. What direct-sampling
> receiver did you mean?
>
> 73, Mike
> www.w0btu.com
>
> On Mon, Oct 12, 2015 at 6:53 PM, Barry N1EU <barry.n1eu@gmail.com> wrote:
>
>> On Mon, Oct 12, 2015 at 10:28 PM, Mike Waters <mikewate@gmail.com> wrote:
>>
>> > But as a recent thread here* established, there is *NO* SDR that can
>> > perform as
>> > well as a good ear-brain combo for copying the very weakest of signals
>> > buried in the noise. Maybe someday, but the future has not arrived yet.
>> :-)
>> >
>> >
>> The statement is a bit ambiguous. I don't know what you mean by "SDR" in
>> the statement above. If you're talking about dsp noise reduction versus
>> no
>> noise reduction, I agree. But if you're talking about direct sampling
>> digital receivers (SDR) versus superhet receivers, I categorically
>> disagree.
>>
>> 73, Barry N1EU
>>
>
>
_________________
Topband Reflector Archives - http://www.contesting.com/_topband
|