[Elecraft] external soundcards for digimodes
Just to say many thanks for the numerous really helpful replies I received (on- and off-reflector) to my queries about using external soundcards for digimodes. I now know exactly what I need to do before the K3 arrives. 73 Chris, MØPSK (and just a tiny bit jealous of Tom, K3PSK) ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
RE: [Elecraft] external soundcards for digimodes
Chris, Built on the motherboard type sound cards need to be checked before using them for more than just listening. Many, but not all, are designed to provide signals for cheap computer type speakers. This means that the audio bandpass is pre-distorted to match these speakers. Often this means a boosted bass and sometimes boosted treble. All Windows versions have some control of this depending on the driver in use. However, sometimes this is designed into the chipset and changing it in Windows makes it worse. The other problem I have had is excessive noise. Power supply, chip noise you name it. One that I measured barely made -40db noise floor. This may not sound so bad, broadcasters are to make -60 min. for the entire system. In this case the card is too noisy adding it to a system makes the noise worse. Many third party audiophile type sound cards both internal and external have flat response and noise floor well beyond -60db. Most have better bypassing and dynamic range. Another difference could be that these cards often sample out to 96K and some even higher sample rates, a benefit if experimenting with SDR. Your software may not use the extra resolution or the sample rate, but a card capable of better will generally do better even in the lesser mode. Good Luck Richard Kent My own interest in the K3 is principally (but not exclusively) the digimodes. For that reason I was interested in the suggestion of Simon, HB9DRV that there might be an operational gain in using a better sound card than that on the PC motherboard. I don't know enough about computing to make judgements, and it would help me (and others in my position) if more knowledgeable and experienced folk on the list could offer advice on the following questions. Q1.Does experience suggest that there can be an observable operational gain in using a sound card different from that built into the PC? Q2.Which published technical specifications of a sound card are relevant to digimode operation? Q3.On the basis of the answer to Q2, how does one judge whether one sound card is better than another for digimode operation? Q4.Do list members have specific recommendations for cost-effective external sound cards? (The sound card suggested by Simon costs around as much in the UK as the 100W upgrade for the basic K3.) 73 Chris, MØPSK ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] external soundcards for digimodes
At 12:19 PM 8/16/2007, David Cutter wrote: The SSM2165 is a good speech compressor and not expensive. I'm assuming it will work on data? to bring up the level as required. wonder if the control of the existing SSM2165 on the K2's ssb board is adequate to optimize the data bill ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
RE: [Elecraft] external soundcards for digimodes
The SSM2165 is a good speech compressor and not expensive. I'm assuming it will work on data? to bring up the level as required. You don't want compression on data modes. Better to use a good low noise, single rail op amp with a low noise reference as a preamplifier to bring the maximum receive level up to 4 V P-P. Compression effects the characteristics of some data modulation modes (one reason for the suggestions to not run any transmit ALC with data modes other than FSK). 73, ... Joe, W4TV -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of David Cutter Sent: Thursday, August 16, 2007 1:19 PM To: Joe Subich, W4TV; 'Michael Keane K1MK'; 'Elecraft Reflector' Subject: Re: [Elecraft] external soundcards for digimodes The SSM2165 is a good speech compressor and not expensive. I'm assuming it will work on data? to bring up the level as required. You can get a complete kit from www.box73.com DYC-817 (Code 734980) External dynamic compressor kit for FT-817. Or from OK1CDJ, but I can't find the link at the moment. This will incur some extra noise, but there are components to adjust to optimise compression etc. David G3UNA - Original Message - From: Joe Subich, W4TV [EMAIL PROTECTED] To: 'Michael Keane K1MK' [EMAIL PROTECTED]; 'Elecraft Reflector' elecraft@mailman.qth.net Sent: Thursday, August 16, 2007 5:50 PM Subject: RE: [Elecraft] external soundcards for digimodes Obviously, the performance specs for a 24-bit sound card should be better than for a 16-bit card. Does anyone know which software apps actually do make use of the extra bits and the higher performance of a 24-bit sound card? There is not much that can be done in the application to take advantage of the 24 bit sound cards. All of the devices are limited on the strong signal end of the spectrum by their power supply (typically 5 volt) which limits the signal to the ADC to about 4.5 volts p-p. On the low signal end, the digital software is limited by the noise level from a quiet band (receiver IF noise, atmospheric noise, etc.) at the receiver output. From memory, most receivers I've seen show composite noise floors about 80 dB below their peak output (peak output is generally around 200 mV average or somewhat less than 1 volt p-p) with no antenna and quiet band noise around 70 dB below maximum output. Even if the DSP algorithms in the digital software could get 10 dB below the noise, the 16 bit sound cards with their 95 to 97 dB theoretical dynamic range would be more than enough for most amateur work at HF. They key to getting everything you can with soundcard modes on HF is having a very low noise audio amplifier between the receiver and ADC (it may be in the soundcard) and minimizing any power supply and logic noise in the sound card. If you will be using AGC and narrow filters in the receiver (one key to maximum weak signal effectiveness), the receiver AGC will limit the dynamic range into the sound card to well less than 40 dB (the difference between MDS and AGC threshold) in any case. You want the peak audio to be as close to the 4 V p-p point as possible to make maximum use of the sound card's available dynamic range as you can. If the maximum signal to the ADC is only one volt p-p you have already given away 12 dB of DR! 73, ... Joe, W4TV -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Michael Keane K1MK Sent: Thursday, August 16, 2007 11:49 AM To: Elecraft Reflector Subject: Re: [Elecraft] external soundcards for digimodes At 09:08 AM 8/16/2007, Don Wilhelm wrote: Typically, the more bits in the Soundcard A-D conversion, the better the dynamic range. There is also the noise floor of the soundcard to consider. Most internal soundcards are 16 bit while the upgrades are typically 24 bits for the A-D. Obviously, the performance specs for a 24-bit sound card should be better than for a 16-bit card. However, in his review of sound cards for Amateur Radio that appeared in the May 2007 QST, Jonathan Taylor, K1RFD wrote that very few digital-mode apps are designed to take advantage of the higher precision when it is available. Does anyone know which software apps actually do make use of the extra bits and the higher performance of a 24-bit sound card? 73, Mike K1MK Michael Keane K1MK [EMAIL PROTECTED] ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
[Elecraft] external soundcards for digimodes
My own interest in the K3 is principally (but not exclusively) the digimodes. For that reason I was interested in the suggestion of Simon, HB9DRV that there might be an operational gain in using a better sound card than that on the PC motherboard. I don't know enough about computing to make judgements, and it would help me (and others in my position) if more knowledgeable and experienced folk on the list could offer advice on the following questions. Q1.Does experience suggest that there can be an observable operational gain in using a sound card different from that built into the PC? Q2.Which published technical specifications of a sound card are relevant to digimode operation? Q3.On the basis of the answer to Q2, how does one judge whether one sound card is better than another for digimode operation? Q4.Do list members have specific recommendations for cost-effective external sound cards? (The sound card suggested by Simon costs around as much in the UK as the 100W upgrade for the basic K3.) 73 Chris, MØPSK ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] external soundcards for digimodes
I've tacked answers into your post. - Original Message - From: Chris Gibson [EMAIL PROTECTED] Q1.Does experience suggest that there can be an observable operational gain in using a sound card different from that built into the PC? DRV Depends on built-in card, laptops are usually foul as are soundcards on the motherboard in general (generalisation). Q2.Which published technical specifications of a sound card are relevant to digimode operation? DRV Dynamic range, for example: http://www.m-audio.com/products/en_us/Delta44-focus.html Q3.On the basis of the answer to Q2, how does one judge whether one sound card is better than another for digimode operation? DRV Less intermod, less noise, less spurious signals. Less problems due to strong adjacent signals. Q4.Do list members have specific recommendations for cost-effective external sound cards? (The sound card suggested by Simon costs around as much in the UK as the 100W upgrade for the basic K3.) DRV External is a good idea as you can take it with you and it avoids noise from the PC. SignaLink USB is good enough, don't know whether there is a K3 cable yet. FWIW the Delta-44 is GBP85 in the UK. 73 Chris, MØPSK ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] external soundcards for digimodes
On 8/16/07, Chris Gibson [EMAIL PROTECTED] wrote: [snip] Q4.Do list members have specific recommendations for cost-effective external sound cards? (The sound card suggested by Simon costs around as much in the UK as the 100W upgrade for the basic K3.) To be honest, notwithstanding Simon's comments, I'm skeptical of the benefit of using an external sound card for ordinary data modes. There are documented benefits for using one for SDR, but that is another matter. I admit I have never tried using a laptop for radio use, but the sound card chips on the laptop motherboards seem to be the same as those used on desktop motherboards so I can't imagine it makes much difference. I find I can get pretty good copy of PSK31 (and CW, come to that) using a Dell Axim PDA running PocketDigi sitting next to the K2 in its cradle and receiving the audio from the loudspeaker via its built-in microphone. Obviously, the copy isn't as good as on the PC with a direct connection. But I think it shows that for modes like that, the quality of the input really isn't that critical. I've seen greater differences between different decoding programs. I think MixW is slightly better than programs that use the PSK Core DLL, for example. There are arguments for using an external sound card, such as being able to keep the built-in sound card for other uses. But I wouldn't go splashing out on an external sound card just on the suggestion that it might give better results. Chances are, it will make no discernible difference. -- Julian, G4ILO K2 s/n: 392 K3 s/n: ??? G4ILO's Shack: www.g4ilo.com Ham-Directory: www.ham-directory.com ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] external soundcards for digimodes
Chris, Typically, the more bits in the Soundcard A-D conversion, the better the dynamic range. There is also the noise floor of the soundcard to consider. Most internal soundcards are 16 bit while the upgrades are typically 24 bits for the A-D. The Soundblaster Live or Soundblaster Audiogy are good alternatives IMHO, are available in USB connected external versions as well as internal cards and will do a good job overall. They are a bit more noisy than the Delta-44, but not a pricey. Depending on your applications and your OS, there may be some differences in the drivers available - check the various forums to get a feeling for any troublespots - the SDR forums are a good resource for that information. I doubt that you will notice a great difference with the better cards for most data modes, although your receiving noise floor could be improved with a good 24 bit card. If you have interest in Software Defined Radio, go for the best you can find that fits within your budget. 73, Don W3FPR Chris Gibson wrote: My own interest in the K3 is principally (but not exclusively) the digimodes. For that reason I was interested in the suggestion of Simon, HB9DRV that there might be an operational gain in using a better sound card than that on the PC motherboard. I don't know enough about computing to make judgements, and it would help me (and others in my position) if more knowledgeable and experienced folk on the list could offer advice on the following questions. ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] external soundcards for digimodes
In casual operation, I doubt you'll see much difference. However, if you are planning on operating during a contest, or otherwise want to use a wide audio path (SSB bandwidth) with AGC OFF (so strong stations don't smother weak ones via AGC action) and with lots of signals simultaneously present, then you'll want a system with very low IMD. The least expensive soundcard that I own that does a reasonable job with SDR (and by extension should do a reasonable job under the conditions I described) is the Creative Soundblaster MP3+. This is a USB-based widget, and you can buy these from Creative's online shop, refurbished, for $14.99. 73, Lyle KK7P ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] external soundcards for digimodes
At 09:08 AM 8/16/2007, Don Wilhelm wrote: Typically, the more bits in the Soundcard A-D conversion, the better the dynamic range. There is also the noise floor of the soundcard to consider. Most internal soundcards are 16 bit while the upgrades are typically 24 bits for the A-D. Obviously, the performance specs for a 24-bit sound card should be better than for a 16-bit card. However, in his review of sound cards for Amateur Radio that appeared in the May 2007 QST, Jonathan Taylor, K1RFD wrote that very few digital-mode apps are designed to take advantage of the higher precision when it is available. Does anyone know which software apps actually do make use of the extra bits and the higher performance of a 24-bit sound card? 73, Mike K1MK Michael Keane K1MK [EMAIL PROTECTED] ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
RE: [Elecraft] external soundcards for digimodes
Obviously, the performance specs for a 24-bit sound card should be better than for a 16-bit card. Does anyone know which software apps actually do make use of the extra bits and the higher performance of a 24-bit sound card? There is not much that can be done in the application to take advantage of the 24 bit sound cards. All of the devices are limited on the strong signal end of the spectrum by their power supply (typically 5 volt) which limits the signal to the ADC to about 4.5 volts p-p. On the low signal end, the digital software is limited by the noise level from a quiet band (receiver IF noise, atmospheric noise, etc.) at the receiver output. From memory, most receivers I've seen show composite noise floors about 80 dB below their peak output (peak output is generally around 200 mV average or somewhat less than 1 volt p-p) with no antenna and quiet band noise around 70 dB below maximum output. Even if the DSP algorithms in the digital software could get 10 dB below the noise, the 16 bit sound cards with their 95 to 97 dB theoretical dynamic range would be more than enough for most amateur work at HF. They key to getting everything you can with soundcard modes on HF is having a very low noise audio amplifier between the receiver and ADC (it may be in the soundcard) and minimizing any power supply and logic noise in the sound card. If you will be using AGC and narrow filters in the receiver (one key to maximum weak signal effectiveness), the receiver AGC will limit the dynamic range into the sound card to well less than 40 dB (the difference between MDS and AGC threshold) in any case. You want the peak audio to be as close to the 4 V p-p point as possible to make maximum use of the sound card's available dynamic range as you can. If the maximum signal to the ADC is only one volt p-p you have already given away 12 dB of DR! 73, ... Joe, W4TV -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Michael Keane K1MK Sent: Thursday, August 16, 2007 11:49 AM To: Elecraft Reflector Subject: Re: [Elecraft] external soundcards for digimodes At 09:08 AM 8/16/2007, Don Wilhelm wrote: Typically, the more bits in the Soundcard A-D conversion, the better the dynamic range. There is also the noise floor of the soundcard to consider. Most internal soundcards are 16 bit while the upgrades are typically 24 bits for the A-D. Obviously, the performance specs for a 24-bit sound card should be better than for a 16-bit card. However, in his review of sound cards for Amateur Radio that appeared in the May 2007 QST, Jonathan Taylor, K1RFD wrote that very few digital-mode apps are designed to take advantage of the higher precision when it is available. Does anyone know which software apps actually do make use of the extra bits and the higher performance of a 24-bit sound card? 73, Mike K1MK Michael Keane K1MK [EMAIL PROTECTED] ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] external soundcards for digimodes
The SSM2165 is a good speech compressor and not expensive. I'm assuming it will work on data? to bring up the level as required. You can get a complete kit from www.box73.com DYC-817 (Code 734980) External dynamic compressor kit for FT-817. Or from OK1CDJ, but I can't find the link at the moment. This will incur some extra noise, but there are components to adjust to optimise compression etc. David G3UNA - Original Message - From: Joe Subich, W4TV [EMAIL PROTECTED] To: 'Michael Keane K1MK' [EMAIL PROTECTED]; 'Elecraft Reflector' elecraft@mailman.qth.net Sent: Thursday, August 16, 2007 5:50 PM Subject: RE: [Elecraft] external soundcards for digimodes Obviously, the performance specs for a 24-bit sound card should be better than for a 16-bit card. Does anyone know which software apps actually do make use of the extra bits and the higher performance of a 24-bit sound card? There is not much that can be done in the application to take advantage of the 24 bit sound cards. All of the devices are limited on the strong signal end of the spectrum by their power supply (typically 5 volt) which limits the signal to the ADC to about 4.5 volts p-p. On the low signal end, the digital software is limited by the noise level from a quiet band (receiver IF noise, atmospheric noise, etc.) at the receiver output. From memory, most receivers I've seen show composite noise floors about 80 dB below their peak output (peak output is generally around 200 mV average or somewhat less than 1 volt p-p) with no antenna and quiet band noise around 70 dB below maximum output. Even if the DSP algorithms in the digital software could get 10 dB below the noise, the 16 bit sound cards with their 95 to 97 dB theoretical dynamic range would be more than enough for most amateur work at HF. They key to getting everything you can with soundcard modes on HF is having a very low noise audio amplifier between the receiver and ADC (it may be in the soundcard) and minimizing any power supply and logic noise in the sound card. If you will be using AGC and narrow filters in the receiver (one key to maximum weak signal effectiveness), the receiver AGC will limit the dynamic range into the sound card to well less than 40 dB (the difference between MDS and AGC threshold) in any case. You want the peak audio to be as close to the 4 V p-p point as possible to make maximum use of the sound card's available dynamic range as you can. If the maximum signal to the ADC is only one volt p-p you have already given away 12 dB of DR! 73, ... Joe, W4TV -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Michael Keane K1MK Sent: Thursday, August 16, 2007 11:49 AM To: Elecraft Reflector Subject: Re: [Elecraft] external soundcards for digimodes At 09:08 AM 8/16/2007, Don Wilhelm wrote: Typically, the more bits in the Soundcard A-D conversion, the better the dynamic range. There is also the noise floor of the soundcard to consider. Most internal soundcards are 16 bit while the upgrades are typically 24 bits for the A-D. Obviously, the performance specs for a 24-bit sound card should be better than for a 16-bit card. However, in his review of sound cards for Amateur Radio that appeared in the May 2007 QST, Jonathan Taylor, K1RFD wrote that very few digital-mode apps are designed to take advantage of the higher precision when it is available. Does anyone know which software apps actually do make use of the extra bits and the higher performance of a 24-bit sound card? 73, Mike K1MK Michael Keane K1MK [EMAIL PROTECTED] ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
