Engine noise level testing for GPS_LOG WinCE

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GPS_LOG WinCE is capable of using computer microphone to record noise level in IGC log file. At this point this is an experimental function and is not enabled by default. In order to enable it you have to create a file in "My Documents" folder on your computer. This file has to be named "ENLset.txt" and is a simple one line ASCII (not Unicode) text file. A default file is distributed in installer packages, but it is not installed.

Before enabling GPS_LOG engine level recording, you should run this test program overnight and make certain that nothing bad happens. Program will keep the PDA awake for the duration. Problems can range form perfect operation to PDA hanging up.

Program has two settings: bandwidth (number in the 100-1000 range), and filter order (checkbox - checked is a steeper filter). Use the [Set] button to
implement changes.

Program displays a number in range between 0 and 999 that represents sound level. In order to get proper recordings one should turn off automatic gain control (AGC) of the microphone in PDA system setttings and adjust manual gain to get appropriate readings with engine on and off. Relevant IGC specifications (from 2003) are in the paragraph below: Recorded ENL values. Figures at or close to the maximum ENL
value of 999 should be recorded in the IGC file as a result of loud noises
such as the running of 2-stroke engines under high power and with
the GNSS FR in a typical position in a glider cockpit. Less noisy engines
(4-stroke and Wankel (rotary) engines) may not produce such high figures,
but must still result in ENL values over 750 (and preferably 800) when
forward thrust is being produced, so that engine or propeller running
can be clearly identified. At the other end of the scale, quiet gliding
flight must result in low but positive ENL readings so that the system is
seen to be self-checking with each fix. Periods showing 000 are not
acceptable and figures varying around 020 should be achieved in quiet
flight in a well-sealed sailplane. Other cockpit noises such as in gliding
flight with cockpit ventilation and other panels open (with and without
sideslip) must be recorded at sufficiently low values so that they cannot
be mistaken for use of engine. In the case of sideslip with panels open
at thermalling speeds, ENL should be less than 300 and preferably 200.

In addition to the sound level, program displays number of re-starts of the recording system. This number should be always zero. Restart is done only if the recording system seems to malfunction. Re-starting can lead to unpredicatble results, including hanging up a PDA. It works fine in simulated failures, but no guarantees on real ones.

Downloads:   (check ReadMe.txt file in archive for installation)

OS3 devices (PocketPC, PocketPC 2002)

PocketPC 2003

Windows Mobile 5 and higher