N8LP wrote:
...Unless you live near a shortwave broadcast station, or
have a high power ham nearby on the same band, you're not likely to
need 130dB BDR anyway. Even in those cases, having 200dB BDR
probably wouldn't help unless there is a LOT of improvement in
transmitter spurious emissions,
--- On Wed, 2/25/09, Bill W5WVO w5...@cybermesa.net wrote:
This point is brought home all the time here in Albuquerque, where we have to
deal with the radiation from ten or more TV/FM analog transmitters
line-of-sight on top of Sandia Crest. While all these transmitters except
Channel 2 have
Although my contesting this past weekend was severely interrupted by
a non-K3 related hardware failure, over the course of the contest I
did use the K3 throughout all day and night segments on various
bands.
I did not call CQ except for a very little bit and the majority was
SP on all bands
: Wednesday, February 25, 2009 9:41 AM
To: Elecraft@mailman.qth.net
Subject: Re: [Elecraft] K3 receiver desensing on CW during contest
Although my contesting this past weekend was severely interrupted by
a non-K3 related hardware failure, over the course of the contest I
did use the K3 throughout
Jim,
Ditto here. #1129. AGC slope= 13, AGC THR =8. AGC set to fast. Never
touched the RF gain control.
I was totally amazed to be able copy weak ones under strong ones within
the passband.
Experienced none of the mushing reported here.
However, when I first got the K3, I did manage to
KE4WY:
Never any desensing in the presence of strong signals observed with my K3.
KA1J:
I noticed no desensing with the K3 in the presence of strong signals.
I agree. 160 is the ultimate test for dynamic range (and desense or BDR)
for any rig. Operating SOSB/160 I never experienced *any*
Those are impressive numbers, Eric. +5dBm would only be about 120dB above the
background noise level on 40m here on a typical night, though. I am located
in a relatively quiet area, but on the edge of suburban/rural. Of course, I
don't have a Yagi currently, and I'm not on the East Coast or in
alsopb wrote:
Ditto here. #1129. AGC slope= 13, AGC THR =8. AGC set to fast. Never
touched the RF gain control.
I was totally amazed to be able copy weak ones under strong ones within
the passband.
Experienced none of the mushing reported here.
The mushing requires 10-15+
On Wed, 25 Feb 2009 01:50:18 -0700, Bill W5WVO wrote:
While all these transmitters except
Channel 2 have fundamentals well above 54 MHz (I run a DCI bandpass filter to
keep it out of my preamp), the accumulated grunge from the transmitters'
perfectly legal low-level spurious emissions and
Larry N8LP wrote on 24 Februay 2009, at 02:40.
I think the days of receivers with xtal filters are numbered. High speed
ADCs capable of 140dB dynamic range without xtal filtering are on the
horizon. A 20-bit ADC with enough processing gain would do it.
--
Let's see: 122 to 140dB: only 15% increase! a walk in the park...
; - )
David
G3UNA
Geoffrey Mackenzie-Kennedy gm4...@btinternet.com wrote:
Larry N8LP wrote on 24 Februay 2009, at 02:40.
I think the days of receivers with xtal filters are numbered. High speed
ADCs capable of
Geoffrey Mackenzie-Kennedy wrote:
Larry N8LP wrote on 24 Februay 2009, at 02:40.
I think the days of receivers with xtal filters are numbered.
So don't put the old horse out to pasture just yet :-)
I recall Icom's President Mr. Inouye saying something similar to Larry's
comment
Not today... but give it a couple years. There is a lot of RD being
poured into this by a number of competing chip manufacturers. Even if
the next batch of designs falls a little short, an all digital design
with BDR close to the best conventional designs would probably enjoy a
very
I agree this is something amateur equipment manufacturers like Elecraft
should be keeping their eye on. If Analog Devices or someone came out
with an under-$100 ADC with performance close to the K3, then you could
save a lot of money and complexity by going to a directly-sampled RF
front end
You may be right, Al. I think the improvements may be incremental, and
distributed among various aspects of the design, not just the ADC. For
instance, ultra-low jitter clock sources, faster FPGAs with improved IP
cores, etc. I think most hams would be thrilled with an improvement to 130dB
BDR,
At the W1KM contesting site, we routinely see signals of +5 dBm or
louder on/near 40m from SWBC stations (using a single Yagi). We also
have two modest-power local AM stations (1 to 5 kW, a few miles away)
just below 1500 kHz that show up even a bit stronger than that on our
160m antennas.
Mike I believe there are two separate parts to your post:
At 50Hz width it was quite clear that many stations call off frequency.
Using RIT, I could see that it was typical for them to be 70Hz or more away
from the DX station but I could not hear them in my 50Hz passband. The real
problem
Hi Wayne and all:
My filters are 200, 400, 1.0, 1.8 and 2.7 and they are all CW enabled. I
was using headphones and my sub RX was off. My serial number is 2208 and the
radio was factory assembled (including the sub RX).
I did not hear key clicks when this was happening. The off frequency
K2MK wrote:
I thought it was interesting that recovery was noticeably slow on the DX
station's frequency when this was happening. However, under normal
conditions when US stations were calling directly on top of the DX
station,
recovery was fast. Hence the ability to copy the DX
Hi Bill:
Here are my CONFIG settings related to the AGC. The only ones I played with
during the contest were SLP and THR. I always use AGC-F but did occasionally
try AGC-S.
AGC-HOLD 000
AGC-PLS NOR
AGC-SLP 010
AGC-THR 005
AGC-F 120
AGC-S 020
The differing conditions I described
Aha. It sounds like the desense problem arises when the DSP filter
is narrower than the roofing filter. A strong station within the
roofing passband but outside the DSP passband will shut down the
receiver through AGC.
I think we all misled ourselves by the impression that desense was
Of K2MK
Sent: Monday, February 23, 2009 11:00 AM
To: btipp...@alum.mit.edu; Elecraft Reflector
Subject: Re: [Elecraft] K3 receiver desensing on CW during contest
Hi Bill:
Here are my CONFIG settings related to the AGC. The only ones I played
with during the contest were SLP and THR. I always use
Peter Wollan-2 wrote:
Aha. It sounds like the desense problem arises when the DSP filter
is narrower than the roofing filter. A strong station within the
roofing passband but outside the DSP passband will shut down the
receiver through AGC.
I think we all misled ourselves by the
Hi Mike,
On Mon, Feb 23, 2009 at 11:00 AM, K2MK k...@comcast.net wrote:
Here are my CONFIG settings related to the AGC. The only ones I played with
during the contest were SLP and THR. I always use AGC-F but did occasionally
try AGC-S.
AGC-HOLD 000
AGC-PLS NOR
AGC-SLP 010
AGC-THR
K7TV
- Original Message -
From: Barry N1EU barry.n...@gmail.com
To: elecraft@mailman.qth.net
Sent: Monday, February 23, 2009 9:59 AM
Subject: Re: [Elecraft] K3 receiver desensing on CW during contest
Peter Wollan-2 wrote:
Aha. It sounds like the desense problem arises when the DSP
Hi Bill:
You stated it correctly. Here's an example.
There are two US stations calling the DX. Me and you both within my 50Hz
passband. I send my call once and you send your call twice. You are S9 at my
receiver and the DX is S7. When I finish calling I can hear you and I can
also hear the DX
Is my summary of the issue correct?
If both signals are within both the DSP and roofing filter bandwidths, then
the receiver recovers instantly after each character.
If the stronger signal is outside the DSP filter window (and you can’t hear
him) but inside the roofing filter window, then
It seems that this thread is VERY confused about how AGC works to
control the RF gain. I also suspect that some are using the radio
with too much RF gain. The settings that W4ZV posted are pretty
much what I use, except that I regularly also run the RF gains
(both main and sub) at about 2
...@carolina.rr.com
- Original Message -
From: Jim Brown j...@audiosystemsgroup.com
To: Elecraft List elecraft@mailman.qth.net
Sent: Monday, February 23, 2009 1:46 PM
Subject: Re: [Elecraft] K3 receiver desensing on CW during contest
It seems that this thread is VERY confused about how AGC
From what I though the original post was about the trouble copying signals
in a pile up, it appears to me that thread has become at least 3 different
topics.
Seems there are people talking desense, AGC settings, and the pile up
problem.
To make mine clear, I do not have any desense
: [Elecraft] K3 receiver desensing on CW during contest
Is this correct?
If a cw signal falls within the DSP passband it should and will pump the
AGC. If a CW signal falls outside the DSP passband it should not pump
the DSP's AGC. Steve Ellington
n...@carolina.rr.com
Hi John:
You are correct. When there was no strong off center signal but two or more
strong signals within the 50Hz passband it was possible to copy one signal,
as we all do, in the presence of QRM. There was no noticeable AGC action. It
was just a normal situation of trying to copy one signal
does anything at all.
Erik K7TV
- Original Message -
From: Darwin, Keith keith.dar...@goodrich.com
To: Elecraft List elecraft@mailman.qth.net
Sent: Monday, February 23, 2009 12:22 PM
Subject: Re: [Elecraft] K3 receiver desensing on CW during contest
I'm at work and don't have time
This is an interesting subject.
I've read several opinions on how the K3-AGC works here and MORE
important: how it behaves.
Can somebody from Elecraft shine a light on the AGC behaviour? I'm very
curious now.
73,
Arie PA3A
__
: Elecraft List
Subject: Re: [Elecraft] K3 receiver desensing on CW during contest
From what I though the original post was about the trouble copying signals
in a pile up, it appears to me that thread has become at least 3 different
topics.
Seems there are people talking desense, AGC settings
When I first received my K3, I too was disappointed with the BDR until I
understood what was happening.
In an effort to quantify the BDR of signals between the xtal filter bandpass
and the DSP bandpass, I set up the following scenario...
Two generators feeding the K3 through a hybrid combiner.
On Mon, 2009-02-23 at 18:40, N8LP wrote:
...
I think the days of receivers with xtal filters are numbered. High speed
ADCs capable of 140dB dynamic range without xtal filtering are on the
horizon. A 20-bit ADC with enough processing gain would do it.
I don't think you'll find a 20-bit ADC
: [Elecraft] K3 receiver desensing on CW during contest
When I first received my K3, I too was disappointed with the BDR until I
understood what was happening.
In an effort to quantify the BDR of signals between the xtal filter
bandpass and the DSP bandpass, I set up the following scenario
I had a great time with my K3 during the ARRL DX contest. I do SP and I was
trolling around with my filter width at 50Hz. Absolutely outstanding. The
auto spot is equally outstanding.
At 50Hz width it was quite clear that many stations call off frequency.
Using RIT, I could see that it was
What IF filters do you have installed?
jim ab3cv
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This is more than likely due to dirty signals on the TX end. I was
using a QS1R connected to the K3 IF and measured the width of some of
the strong signals. Some were as wide as 2.6 kHz Not very good
for a CW signal. In this case there is just not much you can do.
73
Greg
AB7R
On
-boun...@mailman.qth.net] On Behalf Of Gregory Fischer
Sent: Sunday, February 22, 2009 7:59 PM
To: K2MK
Cc: Elecraft Reflector
Subject: Re: [Elecraft] K3 receiver desensing on CW during contest
This is more than likely due to dirty signals on the TX end. I was
using a QS1R connected to the K3
, February 23, 2009 12:45 AM
Subject: [Elecraft] K3 receiver desensing on CW during
contest
I had a great time with my K3 during the ARRL DX contest. I
do SP and I was
trolling around with my filter width at 50Hz. Absolutely
outstanding. The
auto spot is equally outstanding.
At 50Hz width
: elecraft-boun...@mailman.qth.net
[mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Dave Hachadorian
Sent: Sunday, February 22, 2009 6:26 PM
To: Elecraft reflector
Subject: Re: [Elecraft] K3 receiver desensing on CW during contest
The behavior you are describing is almost the same thing I complained
Mike,
The K3 is virtually desense-proof, with a BDR of ~140 dB. But to take
advantage of this, you need a narrow crystal filter -- the closer to
the DSP bandwidth the better. This is exactly the situation that we had
in mind when we designed the 200-Hz 5-pole filter. For CW pileups, you
can't
To: K2MK
Cc: Elecraft Reflector
Subject: Re: [Elecraft] K3 receiver desensing on CW during contest
Mike,
The K3 is virtually desense-proof, with a BDR of ~140 dB. But to take
advantage of this, you need a narrow crystal filter -- the closer to the DSP
bandwidth the better. This is exactly the situation
@mailman.qth.net
Sent: Sunday, February 22, 2009 9:27 PM
Subject: Re: [Elecraft] K3 receiver desensing on CW during contest
Mike,
The K3 is virtually desense-proof, with a BDR of ~140 dB. But to take
advantage of this, you need a narrow crystal filter -- the closer to
the DSP bandwidth the better
...@mailman.qth.net] On Behalf Of wayne burdick
Sent: Sunday, February 22, 2009 7:27 PM
To: K2MK
Cc: Elecraft Reflector
Subject: Re: [Elecraft] K3 receiver desensing on CW during contest
Mike,
The K3 is virtually desense-proof, with a BDR of ~140 dB. But to take
advantage of this, you need a narrow crystal
I believe that I encountered this a couple of times while in VP5 last fall...
there wasn't a roar of stations, the radio just sort of sat there and 'hummed'.
I turned the radio off, then back on, rechecked all of the settings, and kept
going.
Brian N9ADG
--- On Sun, 2/22/09, Merv Schweigert
'
Sent: Sunday, February 22, 2009 11:31 PM
Subject: Re: [Elecraft] K3 receiver desensing on CW during contest
Have to ditto whats been said, I have to run with AGC off, audio set about
3 o'clock and use the RF gain. That seems to work fairly well, I use the
400HZ filter most of the time
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