David,
If you have not read it, the December 2008 issue of QST contains another
review of the Perseus.
Although I own a Perseus, which I bought for use as a piece of test
equipment, I do not own a K3 thus cannot compare their 'sound'. I can say
though that I have never been comfortable with
Dave G4AON wrote:
Members of the RSGB may wish to sneak a preview of the December
RadCom article on SDR where the authors compare a K3 with a HPSDR
Mercury receiver and explain why the SDR sounds better than the K3
(noise through a crystal filter causing phase changes).
I've read the article
Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Dave G4AON
Sent: Saturday, November 08, 2008 6:38 AM
To: elecraft@mailman.qth.net
Subject: Re: [Elecraft] K3 vs. HPSDR Mercury receiver
The explanation from the article is as follows:
When noise pulses/spikes pass
Dave G4AON wrote:
The explanation from the article is as follows:
When noise pulses/spikes pass through a crystal
filter, the phase response of the filter
changes, depending on the noise frequency.
However, when noise pulses/spikes pass
through an ADC with a linear response, the
Dave G4AON wrote:
SDR where the authors compare a K3 with a HPSDR Mercury receiver and
explain why the SDR sounds better than the K3 (noise through a crystal
filter causing phase changes).
The K3 is also an SDR!
--
David Woolley
Emails are not formal business letters, whatever businesses
The explanation from the article is as follows:
When noise pulses/spikes pass through a crystal
filter, the phase response of the filter
changes, depending on the noise frequency.
However, when noise pulses/spikes pass
through an ADC with a linear response, the
phase response stays the same,
For casual SSB operating I listen to my LP-PAN / PowerSDR panadapter which is
fed from ahead of the xtal filters, and for dabbling in contests or
operating CW (where latency can be an issue) I listen to the K3. I am not in
Europe where things can be dicey, but I have yet to see enough total peak
Bill - You wrote:
...we will not see pure SDR rigs (without crystal filter front ends)
be competitive in contest environments.
KM0T is 100% software defined radio with Flex 1000s:
http://www.km0t.com/pages/sdr.htm
and routinely finishes in the top 10 in his category:
James R. Duffey wrote:
I realize that this is not the specific environment you are talking
about.
Correct. VHF Contests and HF Contests are two entirely different animals.
I honestly don't know of *any* serious (i.e. Top Ten class) HF contesters
that use SDRs. However I expect quite a few
Members of the RSGB may wish to sneak a preview of the December RadCom
article on SDR where the authors compare a K3 with a HPSDR Mercury
receiver and explain why the SDR sounds better than the K3 (noise
through a crystal filter causing phase changes).
One way to get better-sounding audio, both on transmit and receive, is
to use a wider-bandwidth crystal filter and let the DSP do most of the
filtering. Because the digital filter is linear-phase it will sound
much more natural than an analog non-linear-phase filter.
That's why I leave ESSB
On Fri, 2008-11-07 at 13:44, Julian, G4ILO wrote:
If crystal filters distort the phase enough to make an audible difference on
speech how the heck do we ever manage to receive PSK through them?
Most of the phase distortion tends to occur at the band edges. As long
as the PSK signal is
If crystal filters distort the phase enough to make an audible difference on
speech how the heck do we ever manage to receive PSK through them?
The phase distortion is most pronounced near the corner frequency of the
crystal filter.
PSK, at least PSK31, is a very narrow mode and the chang
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