ld be fun listening into all the
stations. I have a 1296/28 transverter to use with the K3.
73, Ed - KL7UW
--
Message: 11
Date: Wed, 09 Feb 2011 08:13:19 -0800
From: Vic K2VCO
Subject: Re: [Elecraft] adding 250Hz filer, any improvement?
To: elecraft@mailman.qth.net
M
The "250 Hz" filter has a nominal -6dB bandwidth of 350 to 370 Hz
(see plots at http://www.elecraft.com/K3/filter_plots/250.gif and
www.inrad.net). The 400 Hz filter has a nominal -6dB bandwidth
of 430 - 450 Hz (plots at the same sites).
Since the ultimate selectivity is generated by the DSP, *
On 2/9/2011 8:23 AM, Scott Ellington wrote:
> The additional noise reduction of a narrow crystal filter is negligible.
Right. While a narrower filter reduces the noise bandwidth, the ringing
of a filter with steeper slopes may increase the effects of impulse noise.
> (QRM is another matter.)
I've noticed this effect myself. At super narrow bandwidths, the
signal and remaining noise are both essentially on the same frequency.
With nothing else around to provide a base-line reference, discrimination
becomes a function of real-time delta power measurement rather than tone
dete
I agree with both Don and Bill. There are really two issues:
In the presences of just noise, the DSP with a wider crystal filter is
adequate. The additional noise reduction of a narrow crystal filter is
negligible. (QRM is another matter.)
The brain/ear system, at least for many operators, i
I see that others have told you that you can narrow the DSP and it will be just
as good as
long as there are no nearby signals greater than about S9+20.
Let me add that a huge improvement in copyability of weak CW can be gained by
using the
APF in current firmware. It has a bandwidth (I believ
Ed,
If there are no strong signals on the band or nearby your receive
frequency, then any filter, even the stock 2.7 kHz is sufficient. The
only purpose of the roofing filter is to keep strong signals out of the
receiver passband so they do not activate the AGC and de-sense the
receiver for
Edward R. Cole wrote:
>
> Let me ask a filter question for a different situation. I am
> interested in receiving very-weak CW and currently have the 2.8 KHz
> and 400-Hz 8-pole filters. Will narrowing the DSP bw down to 200-Hz
> work as well as using a 200-Hz filter? There are no strong st
Let me ask a filter question for a different situation. I am
interested in receiving very-weak CW and currently have the 2.8 KHz
and 400-Hz 8-pole filters. Will narrowing the DSP bw down to 200-Hz
work as well as using a 200-Hz filter? There are no strong stations
either nearby or on the ban
I found 8 pole 400 Hz and 5 pole 200 Hz as a great combination in last CQ 160m.
400 Hz filter was to wide most of the time.
73 Robert, S57AW
Sent from iPhone
Na dan 9. feb. 2011, ob 02:30, Wayne Burdick je zapisal:
> On the other end of the spectrum: If the going is really tough, you
> mig
The waterfall in CW Skimmer is extremely accurate for that sort of
thing. Whether you mouse click on a "decoder" (station) or use the
Up/Down arrow keys to jump from one to the next, the zero beat is very,
very accurate. So much so that when I was using CW Skimmer in 3 KHz
audio mode simply
wayne burdick wrote:
>
> On the other end of the spectrum: If the going is really tough, you
> might consider our 200 Hz, 5-pole filter. It's a favorite of CW and
> data-mode operators who routinely have to dig for weak ones between
> monster signals in CW and data modes.
>
I operated mo
On the other end of the spectrum: If the going is really tough, you
might consider our 200 Hz, 5-pole filter. It's a favorite of CW and
data-mode operators who routinely have to dig for weak ones between
monster signals in CW and data modes.
73,
Wayne
N6KR
On Feb 8, 2011, at 11:07 AM, Scott
d the K3's
that the filters were 400's, so they switch in at that dsp bandwidth.
Dave Hachadorian, K6LL
Yuma, AZ
-Original Message-
From: Scott Ellington
Sent: Tuesday, February 08, 2011 12:07 PM
To: Elecraft Reflector
Subject: Re: [Elecraft] adding 250Hz filer, any impr
QRM levels are generally much lower outside EU or NA. Years ago, I did a CW
contest from ZL with a TS-50 and a single 500 Hz filter. That would have been
woefully inadequate in NA, but it was fine there. So, the question I would ask
is whether anyone in a non-EU or NA QTH has compared the K3
On 2/8/2011 9:49 AM, Jorge Diez - CX6VM wrote:
> If I add a KFL3A-250 (250 Hz 8-pole) filter I will notice it better to use
> in contests? Or with the 400Hz is enough?
Jorge,
I find that the 250 Hz filter helps a lot when there are strong signals
very close to a weak station. I bought one a yea
If you have strong stations closer to your frequency than 400 hz, then the
250 hz filter will get rid of them down to 250 hz of your frequency. If the
stations that are near you are not strong, the DSP filter will handle it OK.
-Rex-
K1HI
Rex Lint
Merrimack, NH
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