Hi!
I recall reading about a speaker that you can plug into any radio so you can keep the squelch open all the time and a DSP will only let audio with signals through.
It was intended to be used to listen for beacons on satellites as well as listen for band openings without driving the XYL crazy with static being blasted through the house.
Does anyone else recall this speaker (or inline module)? I've searched and found DSPs that will attenuate white noise, but I haven't seen any that turn off the speaker completely in the presence of white noise alone.
73 de Rich N3WWN
This doesn't ring a bell with anyone?
Maybe I dreamed it! hi hi
73 de Rich N3WWN
On Thu, 29 Mar 2007, n3wwn@futuretek.cx wrote:
Hi!
I recall reading about a speaker that you can plug into any radio so you can keep the squelch open all the time and a DSP will only let audio with signals through.
It was intended to be used to listen for beacons on satellites as well as listen for band openings without driving the XYL crazy with static being blasted through the house.
Does anyone else recall this speaker (or inline module)? I've searched and found DSPs that will attenuate white noise, but I haven't seen any that turn off the speaker completely in the presence of white noise alone.
73 de Rich N3WWN _______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
I thought SGC (The SmartTuner guys) had both a speaker and in-line module at one time. Haven't seen it in a while, though. Jim KQ6EA --- n3wwn@futuretek.cx wrote:
This doesn't ring a bell with anyone?
Maybe I dreamed it! hi hi
73 de Rich N3WWN
On Thu, 29 Mar 2007, n3wwn@futuretek.cx wrote:
Hi!
I recall reading about a speaker that you can plug
into any radio so you
can keep the squelch open all the time and a DSP
will only let audio with
signals through.
It was intended to be used to listen for beacons
on satellites as well as
listen for band openings without driving the XYL
crazy with static being
blasted through the house.
Does anyone else recall this speaker (or inline
module)? I've searched
and found DSPs that will attenuate white noise,
but I haven't seen any
that turn off the speaker completely in the
presence of white noise alone.
73 de Rich N3WWN _______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed
are those of the author.
Not an AMSAT-NA member? Join now to support the
amateur satellite program!
Subscription settings:
http://amsat.org/mailman/listinfo/amsat-bb
Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
I'd like to thank everyone who replied to my inquiry about the DSP speaker!
Thanks to Jeff KB2M, I am now the proud owner of just such a unit which is most pleasing to the XYL's ears!
Thanks again!
73 de Rich N3WWN
On Thu, 5 Apr 2007, n3wwn@futuretek.cx wrote:
This doesn't ring a bell with anyone?
Maybe I dreamed it! hi hi
73 de Rich N3WWN
On Thu, 29 Mar 2007, n3wwn@futuretek.cx wrote:
Hi!
I recall reading about a speaker that you can plug into any radio so you can keep the squelch open all the time and a DSP will only let audio with signals through.
It was intended to be used to listen for beacons on satellites as well as listen for band openings without driving the XYL crazy with static being blasted through the house.
Does anyone else recall this speaker (or inline module)? I've searched and found DSPs that will attenuate white noise, but I haven't seen any that turn off the speaker completely in the presence of white noise alone.
73 de Rich N3WWN _______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
And the winning answer was....?
----- Original Message ----- From: n3wwn@futuretek.cx To: amsat-bb@amsat.org Sent: Wednesday, April 11, 2007 8:59 PM Subject: [amsat-bb] Re: DSP Speaker
I'd like to thank everyone who replied to my inquiry about the DSP speaker!
Thanks to Jeff KB2M, I am now the proud owner of just such a unit which is most pleasing to the XYL's ears!
Thanks again!
73 de Rich N3WWN
On Thu, 5 Apr 2007, n3wwn@futuretek.cx wrote:
This doesn't ring a bell with anyone?
Maybe I dreamed it! hi hi
73 de Rich N3WWN
On Thu, 29 Mar 2007, n3wwn@futuretek.cx wrote:
Hi!
I recall reading about a speaker that you can plug into any radio so
you
can keep the squelch open all the time and a DSP will only let audio
with
signals through.
It was intended to be used to listen for beacons on satellites as well
as
listen for band openings without driving the XYL crazy with static
being
blasted through the house.
Does anyone else recall this speaker (or inline module)? I've searched and found DSPs that will attenuate white noise, but I haven't seen any that turn off the speaker completely in the presence of white noise
alone.
73 de Rich N3WWN _______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the
author.
Not an AMSAT-NA member? Join now to support the amateur satellite
program!
Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite
program!
Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
At 12:04 PM 4/12/2007, Roger Kolakowski wrote:
And the winning answer was....?
That one's got me curious too. I'm particularly fussy about DSP noise reduction, and there are very few that I actually like. The one I use is made by Michels Engineering in Germany, which provides an excellent degree of noise reduction and doesn't distort the audio as severely as many others. For me, that distortion interferes with my ability to pull a signal out of the mud, and most of the DSP noise reductions work best for me in the "off" position, as far as readability goes. The Michaels one, OTOH, has no impact on readability at worst, and often a modest improvement, as well as excellent noise reduction. On very weak FM signals (ideal for SO-50 :) ), the readability is dramatically improved, and the DSP can almost act as an FM voice activated mute.
73 de VK3JED http://vkradio.com
In the DttSP software, the sdr core for PowerSDR (Flex Radio) and others, we have a block LMS approach to automatic noise reduction. It does a really good job of doing noise reduction and automatic notch (your choice) and it definitely does not introduce nasty sounding distortion. It is much more stable than standard LMS based automatic notch filtering. When I developed the algorithm, I was surprised that others had not done it. I then learned of some subtleties which do need mitigation but were pretty straightforward. You adjust the filter once per block rather than once per sample, so you must be careful not to introduce discontinues (distortion) at the block boundaries. Once handled, this is the only way this should be done.
That code is available for svn download (visit the Flex Radio web site or the dttsp-linux yahoo group).
Bob N4HY
Tony Langdon wrote:
At 12:04 PM 4/12/2007, Roger Kolakowski wrote:
And the winning answer was....?
That one's got me curious too. I'm particularly fussy about DSP noise reduction, and there are very few that I actually like. The one I use is made by Michels Engineering in Germany, which provides an excellent degree of noise reduction and doesn't distort the audio as severely as many others. For me, that distortion interferes with my ability to pull a signal out of the mud, and most of the DSP noise reductions work best for me in the "off" position, as far as readability goes. The Michaels one, OTOH, has no impact on readability at worst, and often a modest improvement, as well as excellent noise reduction. On very weak FM signals (ideal for SO-50 :) ), the readability is dramatically improved, and the DSP can almost act as an FM voice activated mute.
73 de VK3JED http://vkradio.com
Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
At 02:04 AM 4/13/2007, Bob McGwier wrote:
In the DttSP software, the sdr core for PowerSDR (Flex Radio) and others, we have a block LMS approach to automatic noise reduction. It does a really good job of doing noise reduction and automatic notch (your choice) and it definitely does not introduce nasty sounding distortion. It is much more stable than standard LMS based automatic notch filtering. When I developed the algorithm, I was surprised that others had not done it. I then learned of some subtleties which do need mitigation but were pretty straightforward. You adjust the filter once per block rather than once per sample, so you must be careful not to introduce discontinues (distortion) at the block boundaries. Once handled, this is the only way this should be done.
That code is available for svn download (visit the Flex Radio web site or the dttsp-linux yahoo group).
Hmm, interesting. Need the radio to run this on though, to evaluate how well it performs. :)
73 de VK3JED http://vkradio.com
Hi Tony, Roger and Bob!
The "winning" unit is an Am-Com ClearSpeech Base Unit. It goes inline between the audio output of the rig and the external speaker. This was based on the reviews on eHam.net ( http://www.eham.net/reviews/detail/1041 ) as well as Jeff's asking price.
No settings, just an on/bypass type toggle switch.
Not being familiar with other DSP units, besides my old Radio Shack DSP 40 http://www.eham.net/reviews/detail/4630 , I was pleasantly surprised by the amount of white noise reduction and astonished by the amount of steady tone elimination that the ClearSpeech unit offers!
The DSP 40 can handle the steady tone elimination somewhat, but the white noise reduction was very poor.
The ClearSpeech Base unit was tested last night on 6m with a semi-local ham (same grid square but about 30 miles away), K3JRD. The noise floor was around S7-S8 and Jim's signal was a S9+, but there was still a lot of white noise in the audio.
I'm actually ahead of myself here... I wanted to test the DSP unit without being "at the radio", so I fired up my 6m rig and tuned to 50.125 USB. With the DSP off, I had the usual loud white noise. With the DSP on, the white noise dropped remarkably. Much to my surprise, about 30 minutes later, I heard K3JRD calling... it was MUCH louder than the white noise, showing how much attenuation was being done.
During the QSO, I disabled and re-enabled the DSP several times to see the difference. It's night and day with my Kenwood TS-660 which has no built-in DSP (not even a notch filter)!
When I get chance I'm going to check out DttSP software that Bob suggested!
Sorry if this is off topic since I haven't had chance to use it on a satellite yet... give me a chance! hi hi
73 de Rich N3WWN
On Thu, 12 Apr 2007, Tony Langdon wrote:
At 12:04 PM 4/12/2007, Roger Kolakowski wrote:
And the winning answer was....?
That one's got me curious too. I'm particularly fussy about DSP noise reduction, and there are very few that I actually like. The one I use is made by Michels Engineering in Germany, which provides an excellent degree of noise reduction and doesn't distort the audio as severely as many others. For me, that distortion interferes with my ability to pull a signal out of the mud, and most of the DSP noise reductions work best for me in the "off" position, as far as readability goes. The Michaels one, OTOH, has no impact on readability at worst, and often a modest improvement, as well as excellent noise reduction. On very weak FM signals (ideal for SO-50 :) ) , the readability is dramatically improved, and the DSP can almost act as an FM voice activated mute.
73 de VK3JED http://vkradio.com
Great unit. I got one a couple of years ago, and am constantly amazed at how well it works. It simply puts to shame the DSP noise reduction in my rig, or the Timewave unit I used before. It worked great on AO-40, which was my reason for getting it. It is less necessary, but still useful, with the LEO birds, both FM and SSB. And all with one switch. I have noticed a sort of "whirring" noise when it is really reaching into a noisy, weak signal. It is just barely perceptible. About half the people I have demonstrated the unit hear it, and the others do not.
Too bad it does not seem to be available any more, as I would like to get the speaker version for mobile operations. Heil had them briefly, but for some reason seems to have discontinued them. I recall one review which something to the effect that while the hardware was rather routine, they had licensed some commercial algorithms from a major telecom. FWIW
Alan WA4SCA
participants (6)
-
Alan P. Biddle -
Bob McGwier -
Jim Jerzycke -
n3wwn＠futuretek.cx -
Roger Kolakowski -
Tony Langdon