Instruction Manual

Wolphi LLC

5949 Whitneyville Av

Alto , Mi 49302

Tel +1 (616) 780-3554


© 2012 Wolphi LLC, All rights reserved.

All trademarks are the property of their respective owners.




HF Weather Fax for Android decodes weather fax 120/576 charts and satellite images through the microphone of your Android phone or tablet.
  • Manual mode / auto mode
  • Spectrum Analyzer for easy tuning on the receiver
  • Automatic start tone and end tone detection (in auto mode)
  • Synchronization at the beginning of the decoding (in auto mode)
  • Auto save recorded images to SD card (in auto mode)
  • Manual start column correction (in auto and manual mode)
  • Manual slant correction (in auto and manual mode)
  • Auto scroll mode
  • Touch screen image zooming
  • Black/white mode with threshold adjustment
  • History screen
  • Timers


Main Screen

Auto Mode: HF Weather Fax for Android can be run in auto mode or with auto mode off. If the auto mode is turned on, HF Weather Fax will automatically:

  • Detect the start tone
  • Synchronize the picture (find the correct start)
  • Decode the image
  • Detect the stop signal
  • Save the image to the SD Card or memory

The status of the sequence will be shown in the status box on the top.
If the auto mode is turned off none of the automatic modes will be enabled. HF Weather Fax will decode all the incoming audio and display it on the screen but the images will not be synchronized and not be saved automatically but can be saved manually by pressing the “save image” button.



Spectrum Scope

To receive a weather fax image you need to set the receiver to USB (upper side band) and the frequency needs to be set 1.9 Khz below the listed carrier frequency.
For example one of the New Orleans listed transmitter frequencies is 12789.9 kHz. To adjust the receiver correctly you need to adjust the frequency to 12788.0 kHz.
The Weather Fax for Android’s spectrum scope also shows the received audio spectrum. When the receiver is adjusted correctly most of the spectrum should appear between the 2 white vertical lines as seen in the picture above.



Scrolling and zooming the image

While receiving, the image can be moved across the screen and zoomed in and out by moving 2 fingers over the touch screen.



Auto Scroll

In auto scroll mode (press the auto scroll button) the images will start to display at the bottom of the screen and will scroll line by line to the top.


Screen timeout

To conserve battery power it is possible to run Weather Fax for Android in the background with the display dimmed or turned of. This setting can be changed by pressing the menu button and then “settings” and then “screen timeout.” The following options can be selected:

  • "screen never turns off” The screen stays on and never turns off
  • "screen dims” The screen dims after the time set in the Android “screen timeout settings”
  • "screen turns off” The screen turns off after the time set in the Android



The image can be displayed in fullscreen mode by pressing the menu button and then pressing the “fullscreen” button.

To return to the regular mode press the “fullscreen” button again


Black and white mode

Weather Fax for Android decodes images in gray scale. For weather charts it is sometimes desired to display pictures only with the 2 colors black and white.
To display the image black and white press the “black/white” button. A slider will appear where the threshold can be adjusted.


Calibrating the phone or tablet

Weather Fax for Android works fully automatic with one exception. Before receiving the first correct image JF Weather Fax for Android needs to be calibrated. Without calibration images will print slanted. The calibrations needs to be done because the transmitter clock will be a little different compared to the Android phone’s/ tablets’s clock (see below). Even a very small difference (less than a part of a million) will cause a slanded image. HF Weather Fax uses and algorithm to compensate the clock difference. The calibration procedure usually needs to be done only once. The following procedure describes the slant calibration:

To begin you need to decode part of of an image. The best way is probably to switch of the auto mode and just decode a fax signal for a couple minutes. By scrolling the image find a line which suppose to be vertical.
Now press the “slant correction” button. (On Android phones press the green “tools” button first)
A red and blue cross will appear on the screen. Move the red cross onto the top left of corner of a line. Then press the “next” button.
Now move the blue cross onto the bottom left corner of the same line. After you released the blue cross the slant should be corrected.
If the picture is still slanted you still can move the blue cross to correct the slant. To finish the calibration process press the “finish” button.



Set Start Column

When decoding an image with the "auto mode" turned off, HF Weather Fax will not synchronize the image and therefore it will not find the start of the image. This can be corrected by pressing the "set start column" button. US HF Weather Fax stations transmit a line synchronization (as seen is the picture below). European stations do not transmit this line

The vertical line can be seen in the middle of the image. To correct the synchronization press the "set start column" button.
Now touch the line in the middle of the image
The image will be adjusted and the black line is now on the edge of the image




To save battery power, Weather Fax for Android’s uses timers which start Weather Fax for Android at customized times during the day.

All timers will be repeated every 24 hours. The checkbox in front of the timer need to be checked to activate the timer.
The timers will wake up the phone/tablet and start HF Weather Fax and close it after the set duration.




All in auto mode received images will be stored on the SD Card or internal memory of the phone or tablet. By pressing the “history” button the stored images will listed.

By clicking an image a image can be displayed. The image can be also be deleted or shared (for example to an email app or printing app).

To save memory old images can be automatically deleted. The auto delete option can be enabled in the settings by clicking the “menu” button and then “settings” then click “automatically delete history images older than”.
The auto delete can be set to:

  • 12 hours
  • 24 hours
  • 7 days
  • 30 days
  • never delete


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After weeks of programming I finished a new Android App – HF Weather Fax.
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