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LP-PAN 2 Installation 1-2-3
Description of LP-PAN system

LP-PAN 2 is a fixed frequency Software Defined Radio. It is tuned to the IF frequency of your radio, and is capable of receiving signals within about +/- 100kHz of the frequency that your rig is tuned to. LP-PAN 2 is basically a wideband direct conversion receiver which converts the IF output of the radio to two wideband audio signals which differ only in that there is a 90 degree phase difference between the channels at all frequencies. These signals are interfaced to the SDR application using a high quality sound card. Almost all of the functionality is provided by the software application, with the outputs being the screen display and sound card speakers (headphones).

The various software packages provide a spectrum display, waterfall display and often the ability to demodulate signals using the standard modes of AM, FM, SSB, CW, etc. The software usually provides DSP filters, noise blankers, noise reduction and notch filtering. It also provides linking to some of the rig's controls, like VFOs, mode and filter width. For modern radios like the K3 and FTdx5000, the user may choose only to use the visual aspects of the SDR app, since the rig already has extensive DSP capability. For users with radios like older Kenwoods or FT-950, the user may want to take advantage of the DSP controls in the SDR, which rival any DSP based radio.

For this tutorial, we will assume that the user is using the following popular components...

K3 or FTdx3000/5000
Asus Xonar U5 or U7 USB sound card
NaP3 v4.0 software

Most of the info provided can be applied to other hardware or software, although the cabling and the software entry screens may be somewhat different.

Connecting LP-PAN to your rig and PC...

Basic interconnection information can be found on the LP-PAN Hardware Installation page.

Installing a sound card...

The Behringer UMC202HD is our current recommended sound card. Installation instructions can be found here, UMC202HD Installation
The Asus U5 and U7 are also excellent performers, but have had a spotty reliability history. Asus U5 / U7 sound card installation info can be found here, Asus U5 / U7 Installation. If you are running Windows XP, you MUST use the U7... the U5 does not support XP. Here is the link for U7 installation using XP... U7 installation page. Refer to the LP-PAN Sound Card page for a discussion sound card recommendations and test results.

Installation and Operation of NaP3...

There are several main apps which we recommend...

The best SDR application is NaP3, developed by Pete Connors, F5VNB. It is based on WU2X's version of the FlexRadio Systems PowerSDRTM software, but includes some unique features developed by Pete, and can even display telnet spots in the pan window from popular web clusters or from CW Skimmer.  Here is the link to our NaP3 installation page.

What are LP-Bridge and LPB2, and when should I use them?

LP-Bridge and LPB2 are special programs which provide several important functions. They provide a method of sharing rig coms with an SDR app and up to five other programs at the same time, like loggers, PSK apps, CW Skimmer, etc. They also provide buffering of the coms to reduce rig traffic and eliminate packet collisions from multiple simultaneous polling requests. Additionally, they provide frequency data for hardware such as SteppIR controllers and amplifiers, and serve as a control center for all the applications that need to talk to the rig.

LP-Bridge is designed for K3, while LPB2 works with K2, K3, Kenwood and recent Yaesu radios (starting with FT-2000). LP-Bridge has slightly more capability, but for most users the two perform similar functions.

Here are links to the setup and installation web pages for the two programs...

LP-Bridge Installation, Setup and Operation
(for sharing of K3 with multiple apps)

LPB2 Installation, Setup and Operation
(for sharing of K2, K3, Yaesu, Kenwood with multiple apps)

CW Skimmer...
Another SDR based application that many users run with LP-PAN is CW Skimmer from Alex, VE3NEA. This program can be run at the same time as NaP3, or separately.  LP-Bridge or LPB2 can be used to integrate the SDR with CW Skimmer. Installation and operation details for CW Skimmer can be found on Alex's website. For configuration tips for sharing CW Skimmer with an SDR, go to our CW Skimmer configuration page.

Basic Troubleshooting

Suggested solution
Display shows noise but no signals
Check audio and RF cabling.

Make sure the correct sound card and driver are selected in NaP3.

For Yaesu rigs, make sure the IF output is turned on in the menus.
There are two sets of signals that move in opposite directions as I tune, ie. there is no image rejection.
Check that you are getting audio from both I & Q channel.

Check sound card settings

Check cabling

Read the section titled
Eliminating Images for a more detailed explanation of the  causes and cures of images.

The audio in the SDR app drops out frequently,
or "motorboats"
Read the excellent paper Vista Tuning for LP-PAN.pdf written by Dave, W8FGU. It is useful for all Windows versions.

Increase the latency setting in NaP3's audio setup.

The sidebands are reversed when I listen to NaP3 output.
Check your audio cabling. If you are using color coded audio cables, the white cable should connect to the Left (I) input of LP-PAN, and red to the Right (Q) input. You can also reverse sidebands by clicking the "Swap IQ" checkbox on the Input tab in NaP3.

There is a “hump” or “hole” in the noise floor near the center of the display.
Check your cabling for a loose connection

Check the Bal/Unbal switch on the back of LP-PAN, or the BAL-UNBAL jumpers on LP-PAN 2.

Check for power supply ground differences between radio and LP-PAN.

Could be the result of using non recommended sound card

Could be an anomaly of the rig's IF output (poor filter matching in an older Kenwood, for instance).

The signal's frequency in the display does not match the rig frequency.
Perform the IF Frequency offset adjustments for your rig as shown on the NaP3 Help page. Make sure your settings match the pictures, except for the Global Offset which will vary slightly from rig to rig. Adjust Global Offset to sync the display with your rig in AM mode if necessary.

Also, make sure I and Q are not swapped.

I get a big red X in the pan display window.
This is generally caused by a bug in NaP3 v4.0. In Setup, in the Display tab under "Band Plan", make sure that the IARU region is set to Region 1 (even if you're not in region 1).

Uninstalling / changing / fixing NaP3 problems...

Many of the problems associated with the software have to do with wrong or corrupt entries in the database files for NaP3. To understand how to address problems and correct them, it helps to know what files are created when the programs are installed, and where they are stored.

The main installation folder can be found in this folder…

C:\Program Files\NaP3

The files in the folder include the program (NaP3.exe), a help file and supporting files. Because of the UAC user account rules in Vista / Windows 7, NaP3 does not save the database files for preferences and settings in this folder, but rather in one of the following AppData (or Application Data) folders…

The folder contains a preferences file, called NaP3.xml. This file contains all the settings from the SETUP section of the program, and other parameters such as WBIR seed values, band stack data, etc. Another file called wisdom is also stored here. This file is created when you first start NaP3 and it calculates the forward and reverse FFTs.

The files can be found in the following paths based on your OS, substituting your user name for the name Larry ...

C:\Documents and Settings\Larry\Application Data\NaP3\NaP3.xml

Vista & Win7


With Vista and Windows 7 you can also enter the following shorthand in Windows Explorer,  %username%\AppData\Roaming\NaP3 to quickly navigate to the file. This shortcut should be entered exactly as typed here (do not change the word "username" to your user name).

It is probably smart to create a shortcut to the appropriate folder for your OS, so that you can easily navigate to these folders in the event that your settings become damaged. It also makes sense to save a backup of the two database files to another folder somewhere.

If it becomes necessary to start over, here is the procedure I would use to uninstall / reinstall NaP3…

Uninstall all versions of NaP3 on your computer using “Add / Remove Programs” or “Programs and Features” in the Control Panels folder. The one to use depends on your OS. I would also delete the NaP3 installation folders in Program Files after uninstalling, and remove the NaP3 folder in the AppData folder. This removes the database files where NaP3 stores your user preferences and settings. The exact path will depend on your OS and whether you chose "Just Me" or "Everyone" when installing NaP3. If you chose "Everyone", and log in with more than one username, you will have to delete the AppData database files for each user, or for "All Users". We recommend using the "Just Me" option.

You will need to substitute your username for "Larry" in the examples. Once you have removed all the NaP3 remnants, NaP3 should install as though it was on a virgin computer. You will need to re-enter all your settings unless you have previously saved a backup of the files.

Support is also available directly from TelePost through at anytime or telephone at 734-455-3716 during normal business hours. There is also a Yahoo User Group at with a large number of helpful users.