is an example of a photo received on a bench test. The received
image is an exact replica of the transmitted image. The color
depth is a full 24 bits.
Images should be carefully selected for size before beginning a transmission. To calculate the transmit time for an image use the following formula:
Time(sec) = W * H / 1000 for black and white
Time(sec) = W * H * 3 / 1000 for color
where the W and H are the dimensions of the photo in pixels. A 200 x 200 image will take 120 seconds to transmit in color and 40 seconds to transmit in b/w. The symbol rate for this mode is 1000 data bytes per second. The color image consists of 3 bytes; red, blue and green for each pixel.
|This is an example of a picture received live on 80 meters (thanks K0OG)|
|You can only transmit an image while in the MFSK-16 mode. The
image can be prepared for transmission while in the receive mode.
Right click in the transmit text box and select "Send Image"
from the popup menu. This will open up the transmit image dialog which
will be blank to start.
Press the "Load" button and a file selection dialog will allow you to select a suitable image for transmit. The file selection dialog also has a preview capability so you will see what the image looks like.
You may also open a window manager file browser and drag and drop an image to the center part of the Send image dialog.
The "X1" button is a three-way toggle that allows you to transmit an image file in
X1 - normal and compatible with other modem programs
X2 - double speed, and
X4 - quadruple speed. X2 and X4 are fldigi specific image modes.
The Send image dialog after the image was drag and dropped onto the dialog.
The properties box said this image was 120 x 119 24 bit color. So it should take 42.8 seconds to transmit in full color. You can send a color or a b/w image in either color mode or b/w mode. If you transmit a color image in b/w the program will convert the image before transmiting. If you transmit a b/w image as full color you are in effect transmitting redundant information, but it can be done. I selected the "XmtClr" button for a trial run. Pressing either the "XmtClr" or "XmtGry" will put the program and the transceiver into the transmit mode if it was in the receive mode. The image is cleared and then repainted as the transmission proceeds. You see the same image progression that the receiving station should see. The main display also displays the % completion on the status bar. Hold the mouse over either the XmtClr or the XmtGry button and the tooltip will tell you the transmit time for this image.
You may abort the transmission at any time by pressing the "Abort Xmt" button. That will return you to the text mode for MFSK. You will then have to toggle the T/R button if you want to return to receive.
The receiving program decodes the "Pic:110x119C;" as a color picture
110 wide by 119 high. Here is shown being received on a computer
running Vista Home Premium.
|This is what the waterfall will look like during the reception of an MFSK-16 image.
The actual spectrum signature will vary with the image bytes being transmitted. The waterfall scale is in the x4 mode and the above photo was being transmitted in 24 bit color for this screenshot. The waterfall clearly shows that the image transmission is within the bandwidth occupied by MFSK-16.