Here is a table of recommended sound cards that have been tested by me with LP-PAN.  Following this section is a discussion of sound card issues for those interested in reading it. The following measurements were made with the K3 ATTEN OFF and K3 PREAMP OFF unless otherwise noted.

Recommended Sound Cards	Input Level Note 1	THD -10dBm input	IP3: -15dBm tones 5kHz spacing	Clip Point K3 PRE On/Off	Noise Floor K3 PRE On/Off	Image Rejection	CPU Usage Note 2
192 kHz
Creative Labs E-MU 0202 USB	Adjustable	-80dB	+20dBm	-15 / -5dBm	-129 / -119 dBm	55-65 dB	35%
Roland Edirol FA-66 Firewire*	Adjustable	-80dB	+20dBm	-15 / -5dBm	-130 / -120dBm Note 3	55-60 dB	27%
96 kHz
Creative Labs E-MU 0202 USB	Adjustable	-80dB	+20dBm	-15 / -5dBm	-129 / -119 dBm	60-70 dB	30%
M-Audio Firewire Audiophile 2496	0dB	-75dB	+20dBm	-15 / -5dBm	-127 / -117 dBm	60-80 dB	9%
Roland Edirol FA-66 Firewire*	Adjustable	-80dB	+20dBm	-15 / -5dBm	-130 / -120dBm	60 dB	20%
M-Audio Delta44 PCI *	-2dB, +4dB	-75dB	+22dBm	-13 / -3 dBm	-130 / -120 dBm	45-60 dB	11%
M-Audio Audiophile 2496 PCI	+1dB	-75dB	+20dBm	-15 / -5 dBm	-127 / -117 dBm	55-75 dB	9%

* Card has a spurious response at 0Hz whether LP-PAN is connected or not. The level is 5-10dB above the noise floor, and will not be noticeable on most bands when connected to an antenna.

1)  Displayed level accuracy when fed with K3 / LP-PAN with K3 preamp and attenuator OFF and LP-PAN set to nominal gain. Delta44 accuracy is shown with two hardware settings from the Delta44 control panel (consumer,  -10dBV).

2) Dell WS360, 2.8GHz P4, 1GB. Software running is PowerSDR-IF Stage, LP-Bridge and Firefox.

3) Card has a peak in noise floor of about 10dB at +/- 75 kHz, with a rolloff of about 15 dB in noise and gain at +/- 96 kHz. This is probably due to the anti-aliasing filter design. That makes the FA-66 useful up to about 150 kHz display bandwidth. Also, note the peak in noise near 0Hz in the SpectraPlus screen capture at the botom of this page. Also, even though this card is supported in PowerSDR, I found it preferable to set the program to "Unsupported Sound Card" and use the manual controls on the card.


General Sound Card Info:

There are several important factors that need to be heeded when selecting a sound card for use with LP-PAN.

Bandwidth... the sampling rate AND bandwidth of the card need to match your desired displayed bandwidth. For a displayed width of ~180 kHz, you need a board with 192 kHz sampling for BOTH "record" and "playback". Most 192 kHz cards are limited to 96 kHz in record. A card with 192 kHz sampling rate will generally provide a bandwidth of about 85-90 kHz. This is determined by the Nyquist limit, plus the response of the anti-aliasing filters. Since both I & Q (in-phase and quadrature) signals are being sampled, the displayed bandwidth is double the actual sound card bandwidth. Bandwidth is also limited by wideband noise. Some 192 kHz cards exhibit rising noise between about 45 kHz and 90 kHz, with a noise floor at 90 kHz that might be 25 dB higher than at low frequencies. Manufacturers don't specify these things, so only testing can determine which cards are usable.

Resolution... The dynamic range and noise floor of the sound card are largely determined by resolution, or bit depth. Dynamic range is the ratio in dB of the maximum signal that can be handled to the noise floor. Inexpensive cards tend to use 16-bit  resolution, which is adequate for a simple spectrum display that is not concerned about maximum dynamic range or noise floor. 24-bit cards are preferred, as they provide 100dB or more dynamic range.

Interface Type... There are several types of sound card interfaces. PCI, USB, Firewire and PCMCIA. PCI cards plug into a desktop PC, while the others will work eith any PC, including laptops, if they have the correct port. It doesn't matter which you use, but I have found that systems with slower processors will work better if you avoid USB interfaces. USB is not a particularly efficient interface, and uses a lot of processor calls and interrupts, which eats up CPU cycles. PCI and Firewire are especially efficient interfaces.

Connections... LP-PAN will work with almost any analog sound card connections, either balanced or unbalanced. You may have to use some commonly available adapters or adapter cables to connect to LP-PAN. If the card only has AES-EBU or SPDIF digital ports, it will not work with LP-PAN. Analog inputs and outputs are required.

Channels... LP-PAN requires 2 channels... one for I and one for Q. Having more channels is OK, and if you use your sound card for other things like a software defined radio with both transmit and receive capability, you may find it useful to have 4 channels. Beware of internal laptop sound cards which sometimes only provide a mono microphone or line input. These will not work with LP-PAN unless you can live with zero image rejection.

Cost... Sound cards range in price from <$50 to as much as $500. It should be possible to find a very good card for use with 96 kHz or 192 kHz sampling rates in the range of $100 to $150 new, and even less on eBay. I have found a couple cards in the $100 range that are excellent performers.