Packet Engine Pro Help

General Information
   
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   Features
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Program Setup

   Radio Port Mgr
    . Edit TNC/modem Port
    . Edit Sound Card Port
       - Tuning Aid
       - Volume Settings
    . Edit Parameters
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   Heard Stations List 
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Tips, Tricks, & Trouble
   Tips and Tricks
   Problems?
   
Sound Card Use
     . Sound Card Interface
     . HF Operations
     . 9600 Operations
     . Receive Problems
     . Transmit Problems

 

Help Date: 21 June 2004

 

 

Sound Card Tuning Aid

The Sound Card Tuning Aid is only accessible from the Radio Port Manager screen and only accessible for sound card radioports. Use the Manager's list to select (or highlight) the port to edit and then, from the menu, select Edit: Tuning Aid or use the Tuning Aid Icon . This will bring up the Tuning Aid Screen.

Oscilloscopes

At least one oscilloscope display will appear on the left side of the screen. A second scope below the first only appears if you have selected Dual Port use of the sound card on the Properties screen.

There are 4 scope display styles available from the drop-down list: Sine Wave, Waterfall, Eye (scatter), and Frequency. The first two will be most useful.

1. Sine Wave - useful for determining the strength of the signal (audio volume) and the quality of the signal. A signal with good strength will fill about 1/2 of the screen (relative distance between the peaks and valleys of the wave). You can use the Volume Control settings for RX (receive) to adjust them. A signal with good quality will display a smoothly flowing wave pattern. Other wave patterns indicate a poor signal which may be indicative of  'on air' packet collisions, poor formed signals from the sending station, or RFI (interference) either on the air on from within your station.

Signal samples for 1200 baud:

Sample of a good signal;
packet decoded.
 

 
Too weak or distant;
no decoding

 
Collision of packets;
no decoding


 
This is from a Yaesu FT209 transceiver with bass boost activated. The boost creates incorrect pre-emphasis: the low tone is emphasized, not the high tone. These packets can only be decoded about 80% of the time. The sending station must turn off bass boost to correct this.

  Signal sample for 9600 baud:


Generally good signal, but you can see small sparks caused by some "bug" at either the transmitting station or your receiver or sound card.

 




2. Waterfall -  This is a frequency spectrum display that shows activity in the audio pass band over the last few seconds. Received signals create color streaks which will 'fall' down the display as time progresses. Relative signal strength is indicated by the colors, which are -- weakest to strongest -- blue, green, yellow, red. Black indicates no signal.

The waterfall should be centered between the two vertical white lines. For AFSK (UHF/VHF), it should center automatically. For HF operations (FSK), adjust the radio's receive frequency to center the waterfall. Centering is critical for accurate decoding of HF packets. The strongest signal (yellow/red color streak) must lie between those two lines, as this next screen shot illustrates:


 

The screen shot below shows an HF radio that needs tuning. The yellow area showing  packet activity is below the tuned frequency marked by the two vertical lines:

 

This sample below is a waterfall display showing two 1200 baud packets. The packets are between the two vertical white lines and have black areas to their left and right.

1200 baud showing 2 packets

The upper packet has fair modulation and was decoded. Also, note the black area above the packet with small green vertical lines. This is the result of TXDelay, i.e. a short interval of carrier with no modulation.

The bottom packet has very low modulation (little color; similar to a carrier with no modulation), but the packet was still decoded.


3. Eye  - is really a scatter diagram. The closer together the scattered points, the better the signal.

4. Frequency - a realtime display of where signals are being heard along a frequency scale. The TWO white vertical lines are centered around the dialed frequency and the majority of signal peaks and valleys should fall between the left line (lower tone) and the right line (upper tone). If they don't, you'll need to change the radio's dialed frequency to center the signal between the white lines.

DCD Lights

There are two DCD (Data Carrier Detect) "LED" confirmation lights, one for each radioport. They will flash green if PE Pro detects a digital signal on the frequency, even if it can't decode it.
 

Equalization Sliders

  The Equalization sliders let you enter an adjustment factor for your sound card clock's timing rate. PE Pro assumes the clock will oscillate at the 11025 Hz sampling rate, but in reality most sound card clocks are usually a few Hz fast or slow. For most packets, the slight timing difference doesn't affect packet decoding and there is no need to change the Equalization slider. But if you are having trouble decoding packets from a distant station, you can try adjusting the slider to compensate for the clock's timing difference.

The default slide setting is at 4 (an arbitrary number). Since PE Pro doesn't know if your clock is slow or fast, trial and error is the only way to determine if any changes up or down will make a difference. Note that changes will only take effect after you restart PE Pro.


Set Volume Button

Pressing this button takes you to the sound card Volume Settings window where you can adjust TX audio levels, RX audio levels, and the RX input source jack.


Copyright 2004 SV2AGW George Rossopoulos . All rights reserved.