# FSQ Image Mode

## Help Information

V0.41, 21.10.2016

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Introduction | Receiving | Transmitting

### Introduction

> FSQ is sufficiently robust that it works very effectively as a Directed Messaging (Selective Calling) system. FSQCALL Directed Messaging offers a series of useful commands that the transmitting station can send, usually manually, and which the receiving station can respond to automatically. One of the unusual functions provided is the ability to transmit and automatically receive - and even to request - digitally managed analogue images!

> Analogue image techniques are used because they are much faster and less error prone than digital techniques. Image transmission in FSQ is very versatile, with three colour picture image sizes: higher and lower resolution, a specialized (but very slow) High Definition colour mode, and a black-and-white very high resolution mode. There are three image sources: from file (photograph, scanned document etc), copy and pasted from other applications, and live from a 'webcam'. The smallest pictures are very quick to transmit, useful for 'selfie shots'. The very high resolution black-and-white mode (like a FAX mode), is ideal for sending documents and drawings, and will render grey-scale well. All modes are received automatically since they are managed using FSQCall Active mode digital commands.

> Image Mode Summary
> Mode | Resolution | TX Time
> LO RES COLOUR | 160 x 120 | 48 sec
> HI RES COLOUR | 320 x 240 | 192 sec
> HD COLOUR | 640 x 480 | 768 sec
> B&W FAX | 640 x 480 | 256 sec

> From the table you can see that there are three sizes of pictures. No matter what size the original image, or the mode used to transmit and receive it, when they are displayed, they are always shown (enlarged as necessary) at 640 x 480 pixels, in a floating window. Enlargement is achieved by interpolation, which gives excellent image appearance.

> Actual size 320 x 240 pixel image.
> It is shown twice this size within FSQCALL

> The above picture was received over the air under ideal conditions - picture quality is remarkable given the modest resolution.

> The modulation is similar to SSTV, i.e. it is analogue FM modulation, but that is where the similarity ends. The FSQ image modes use only 400 Hz bandwidth (similar to FSQ digital transmissions), and like FSQ, there is no synchronization transmitted. Black is transmitted as 1300 Hz, white or full saturation colour as 1700 Hz. The ITU Emission Designator for the image mode is 400HF3C.

> The start of the picture is signalled digitally (i.e using FSQ), and the receiver simply captures data continuously for L lines of P pixels, resulting in a (L x P) pixel image, then reception stops. Each line in a colour picture is sent three times, for red, green and blue components. The duration of transmission is (L x P)/400 seconds for colour, and (L x P)/1200 for B&W. The images are always sent in 4:3 landscape aspect ratio. Images are best sent and received in the default Active mode, since then reception is automatic. Images can be sent to one recipient, to several recipients, or everyone on the channel, just as with other messages. Images can be sent and received in non-directed vanilla FSQ mode, but reception will need to be started manually, and remote requests are not available.

> > Note:
> > While transmitting or receiving pictures, it is most important that you refrain from typing in the TX buffer, moving windows around, realigning images and even looking for or opening other files. These interrupt-driven actions can incur delays, which are likely to disrupt transmission and reception. It's also not a good idea to do these things while transmitting text.

> > It's best practice to QSY off the calling channel to send longer pictures, as the risk of having them marred by other stations sounding will be high on a busy channel. The other station may not hear your transmission, but be strong at your intended recipient.

> Narrow-Band Images
> FSQ Image Mode was designed (like FSQ) for NVIS propagation on the lower bands, quite different from the intentions of SSTV. Unlike SSTV, the pictures are sent relatively slowly, in a narrow bandwidth (⅓ of SSTV), and as a result the picture signal to noise ratio is generally better than SSTV for the same transmission power. As a guideline, FSQ signals (before the picture is started) need to be about +10dB SNR for noise-free picture reception, although quite adequate pictures may be received at or below 0dB if fading is limited.

> FSQ pictures also offer significantly better reception than SSTV under NVIS conditions. Because there is no picture sync, there is no risk of the picture tearing due to timing changes, or breaking up during selective fades. All that happens is that the image may noise up momentarily, but will stay correctly aligned, as in the first example below.

> Note that there is no hint of image break-up or tearing of the picture in any of these examples, even with fading, and also no sign of multi-path ghosting. These images were all transmitted over a range of 300 km using a 15W transmitter.

> 1. 2. 3.
> Typical reception of FSQ 320 x 240 colour image mode
> (1) 80m at night, with fades; (2) Live webcam shot of ZL1BPU, 80m at night (3) 40m daytime.

> Picture Format
> The image mode sampling rate is 12,000 samples/sec, the same as the text mode. Each pixel consists of 10 samples, and there are 640/320/160 pixels/line. Therefore the line period is 0.5333/0.2667/0.1333 seconds, or 1.875/3.75/7.5 lines/sec. Each line is sent three times (except in B&W FAX mode), in RGB order. Picture transmission duration is given in the table above.

> Pictures in portrait mode can be transmitted by rotating them before transmission, and rotating back after reception. Rotation is external to the FSQCall program (Windows Photo Viewer will rotate and save images). Original photographs of any size can be selected, and will be resampled automatically down to the appropriate size for transmission. A4 documents to be sent in FAX mode should be rotated to landscape format before transmission and returned to correct orientation again after reception.

> No Sync
> As mentioned, there is no horizontal (line) sync sent with the picture, and no vertical sync during or at the start of the picture. As a result, it is possible for reception to start slightly earlier or later than the standard delay from the time of the command, depending on the relative speed of the computers used at either end. This has two main effects: first, the picture may be recorded shifted left or right, and the pixel order (in colour mode) may be wrong. This is easily fixed after reception using the Phase control.

> If the sound cards in the transmitting and receiving computers differ markedly in sample rate, the resulting picture can be skewed. A timing difference of 24ppm is enough to cause a just noticeable (one pixel) slant. This is easily fixed after reception using the Slant control. High quality sound cards should be better than 5ppm, resulting in imperceptable slant, but some cheaper computer built-in sound modules and dongles may be rather worse.

### Reception

> You will be pleased to know that reception is completely automatic. Provided the software at both stations is in FSQCall mode, and the sending station uses the correct callsign and trigger command, the receiving program will identify the picture start, and record the picture. In doing so, it automatically opens the floating 'Image Receive' window. You can also open this manually using the Picture/Receive Pic command from the Menu. Reception will start in HI RES mode, and you may need to stop and restart in the appropriate mode.

> If the transmitting station goes off the air or reception is lost during recording of a picture, the recording will continue until the necessary number of samples have been made before reception stops or the receiving operator stops reception. Digital reception (FSQ) continues during picture reception, which means that if the transmitting station stops for some reason and starts image transmission again, the image reception will restart, even if you've not stopped it.

> The floating Image Receive Window (yes, that's Con ZL2AFP)

> The Image Receive window (shown above) has two groups of image positioning buttons at the top, and several other buttons, in addition to the 640 x 480 image reception area:
> - The upper control button group (Phase) adjust phase (small movement) and colour order (larger movement). Very small movements can be made by using the inner two buttons, and progressively larger movements with the outer buttons. If the phase is correct, but the colours wrong, make a couple of large movements and try again. Adjust so the sides of the picture match the frame, and sky colours are blue, grass is green, skin tones are pink or brown!
> - The lower control button group (Slant) adjust for differences in sound card clock rates. Use these control in the same manner to correct any slight tilt of the picture. These controls have a huge range, to accomodate received pictures from stations with very badly calibrated sound cards.

> A received image before alignment

> You should not use either of these control groups while a picture is being received. Wait until reception has finished before adjustment. Adjustment may be a little slow on older computers. Make the adjustments before saving the picture (see below).

> First correct the Phase (correct it at the top of the picture if there is significant slant), then correct the slant. Finally recheck the Phase if necessary, and then save the picture.

> You should also not type in the TX pane, access files or documents, or prepare an image for transmission, while a picture is being received or transmitted. You risk having the picture shift irretrievably sideways part way through reception. However, pictures will still start automatically (in Directed Mode) if you already have text in the Transmit Pane. It's not wise however, to continue typing while an image is being received, as this may trigger timing shifts on slower computers.

> Mode Controls There are four mode controls on the Image Receive window: the HI-RES START/STOP, LO-RES PIC START/STOP, HD PIC START/STOP and the FSQ-FAX START/STOP buttons. These all function in the same way. It is handy to be able to start picture reception manually if the receive command failed, or your or the other guy's FSQ program is not in Directed Message mode, or if you want to receive a picture not addressed to you. You will need to know from the transmitted header (watch the Monitor pane) which type of reception to start. The command will be followed by a 'L' (large, higher resolution colour) 'S' (small, lower resolution colour), 'V' (Very High Definition colour) or 'F' (B&W FAX mode).

> If you mistakenly receive a low resolution picture as high resolution, wait until the transmission has stopped, then press the LO-RES PIC Start/Stop button, and the picture will be displayed correctly in LO-RES mode. The reverse situation is not fully recoverable, as reception will stop before the complete picture has been received. In this case it's best to start recording again.

> Saving Pictures Either right-click on the image, or uses the Save Pic button in the bottom right corner of the Image Receive window. These actions bring up a file 'Save As' dialog.

> Checking Sound Card Accuracy You should be able to resolve arguments as to who is causing slant on received pictures (you or the other guy?) by checking the accuracy of your sound card. Look for an HF WEFAX station (these transmit pictures at two lines/sec with very high accuracy), and tune (in USB) so the predominant tone is on or just above the right yellow line on the waterfall. (This will be 1kHz lower than the quoted frequency - see NOAA for a list of stations, frequencies and schedules). Manually start image reception in CAL CHECK mode (button at the bottom of the window) and let it receive a full 'picture' (it will be 600 x 400 pixels). There will be a lot of strange symbols, and perhaps diagonal or curved lines. Here's an example:

> WEFAX Sample Rate calibration check

> But look closely! You should be able to see that some of the lines at least are vertical, or near vertical. There is often a strong black vertical bar (in this example a white space) which would be at the edge of the original picture. To some extent results depend on the transmitted picture content, but the vertical lines will be consistently dead vertical if your sound card calibration is correct. WEFAX transmissions have very high timing accuracy. By the way, some sound cards have different sample rates for input and output, and this check does not necessarily give an indication of the transmit sample rate accuracy. It is not possible to compensate for the error in the software, other than by using the Slant control.

> This feature is intended only for calibration check purposes. It is not intended for WEFAX reception. FLDIGI has an excellent automatic WEFAX reception mode.

### Transmission

> Image File Transmission
> First type (or use F1) to enter the recipient callsign direction in the transmit pane, and add the trigger character '%' immediately after the callsign with no quotes or spaces (like this: zl2abc%). Multiple callsign directions with individual triggers can be used, and allcall% will also work. (Directions and triggers can be omitted if not in Active mode, but you should warn recipients what's coming!)

> You can also select the target callsign and image trigger by left and right clicking on the Heard List (top right).

> Then from the Menu, select Picture/Send File Pic. This will open a floating 'Image Send' window.

> Image Send window, before and after image is loaded

> Select the size of image you wish to send, LO-RES (low resolution, 160 x 120), HI-RES (higher resolution, 320 x 240), HD (High Defenition, 640 x 480) or FSQ-FAX (super-high resolution 640 x 480 B&W). It makes little sense to choose a mode that is substantially bigger than the original image, as the resolution won't be improved by the process, and you will simply waste air-time.

> Right-click on the white picture area, where it says 'RIGHT CLICK TO LOAD PICTURE' (or on a previous picture if one is loaded) to bring up a file 'Open' dialog. Select an image, and press Open. All common image types are supported, in any size. When you press Open, the program will resample your image down (or up) to the appropriate size, and display it. Images not in 4:3 aspect ratio will be squeezed to fit, and will need correction at the receive end. Portait mode images should first be rotated left before transmission, or converted to landscape mode using an image editor, as in the 'QSL Card' example below.

> Another way to send portait mode pictures

> Once the image has loaded, you can, if you wish, revise the size you wish to send. Finally, check that you've typed the correct Direction and Trigger in the TX pane, then, if the channel is clear, click on the SEND PIC button on the Image Send window, and the image transmission will start.

> For the first few seconds, the image reception command will be sent in FSQ, followed by the image. The progress of transmission can be followed, as the program places a green progress bar down the right side of the picture on the Image Send window. When the picture transmission has completed, the program reverts to receive. Don't fiddle with anything else on the computer until this happens.

> > Note: The recipient callsign for image transmission can be a single callsign, such as zl2abc%, a list of callsigns (such as zl2abc% zl2cde% zl3fab%), and even allcall% can be used to send the picture to everyone.

> FSQ-FAX Transmission
> The procedure is exactly the same as described above, except you select FSQ-FAX mode. The image must be in landscape format, and can be in colour, although it will be converted to B&W for transmission.

> Copy and Paste
> The Image Send window also has a Paste from Clipboard button. You can select an image, page, screen or object in some other application, copy it to the Windows 'Clipboard', and then use this button to paste the clipboard object into the Image Send window for transmission as a colour picture or FSQ-FAX. Preferably the image you copy should be in approximately 4:3 landscape format. This facility is very convenient for use with Microsoft Paint, which allows you to manipulate an image, enlarge, crop etc, then select and copy to clipboard.

> You can also copy from a text document, even a PDF or WORD document if you first open it in the host application, adjust the window size to suit, and use ALT-PrtScn to copy the window to clipboard. You can't do this with text from an application, but it will work with ALT-PRtScn. This is a very powerful technique, as it means virtually any document, or a screen-shot of any application can be sent. Clearly, highly detailed text documents are best sent in FSQ-FAX mode. Portrait format documents should be sent after rotation, or as two halves.

> You may also be able to capture to clipboard from the applet of a non-supported web-cam, and then paste into the Image Send window for transmission. Any size of image, smaller or larger than the window, may be used, and it will be adjusted to fit the window.

> Webcam Transmission
> First type (or use F1) to enter the recipient callsign direction in the transmit pane, and add the trigger character '%' as previously described.

> Then, from the Menu, select Picture/Send Webcam Pic. This will open a floating Webcam applet window.

> Webcam Send window

> You can use the drop-down just below Webcam controls to select a different camera, if you have one. Use Webcam controls to bring up a further applet (camera dependent) to allow you to change other camera settings. Make sure you leave the resolution at the highest your camera will provide. Press Confirm camera selection. The camera will show a live picture in the applet window.

> The checkbox 'Allow SEND' is a privacy function. It provides a way to disable the camera so that other users cannot request picture transmissions from your camera. This function disables ALL Webcam transmissions, including your own. Remote users (see next section) will instead receive a message 'Webcam not available'. The default state is OFF (camera not available).

> Select the size of image you wish to send, LO-RES (low resolution, 160 x 120) or HI-RES (higher resolution, 320 x 240). The smaller pictures also take 48 seconds to transmit, the larger 192 seconds. As previously described, you can also send 640 x 480 HD images in colour or B&W (FSQ-FAX mode), but these transmissions are very slow, and there will be little point unless you are using an HD camera, as in the webcam example above. Notice that the image shown is live, and remains so until you press the SEND PIC button.

> Position the camera or subject as required. Check that you have the correct direction and trigger set, and that the channel is clear, then press the SEND PIC button to start transmission.

> > Note: Most lap-top built-in cameras should work with the DirectShow driver technology used by the program. If you use an external camera on a laptop, you may need to select the camera manually, as it will have two to choose from. (This would not be helpful for remote image capture - either use the internal web cam, or disable it to use the external one).

### Remote Image Requests

> Exactly the same features for image file transmission are available to other stations, allowing them to request an automatic transmission of any of the images stored on your computer, even if you are not there. This is convenient for reception at times when propagation is good, or when the working channel is less busy. Any popular file format can be received. In the examples below, the request is for a file named "image.jpg". The syntax is similar to that used to receive files.

> > callsign+[%Simage.jpg] 48s 160x120 colour
> > callsign+[%Limage.jpg] 192s 320x240 colour
> > callsign+[%Fimage.jpg] 256s 640x480 B&W (grey-scale)
> > callsign+[%Vimage.jpg] 576s 640x480 colour

> You will see that both the format-defining characters (shown in blue) and the syntax are not the same as for remote web camera reception (below). Transmission will start automatically, and your receive window will open automatically when the transmission starts.

> Each station will have a directory of available images. You can retrieve the directory using a standard file receive command, such as:

> > callsign+[Images.callsign]

> Only images that the station owner wishes you to see are available. These will reside in the Shared/Images folder. When you copy images into your own Shared/Images folder, you need to subsequently select File/Refresh directories from the menu to update the Image directory file.

### Remote Webcam Command

> You can also request a Webcam picture from a remote station! To request a station (known to be equipped with a camera) to send a HI-RES (large) webcam image, send the command 'callsign% W', or for a LO-RES (small) webcam image, send 'callsign% w'. If the remote camera is known to be an HD type (at least 800 x 600 resolution), you can also use 'callsign% f' for a B&W 640 x 480 image, or for an HD colour image, send 'callsign% v'. Using 'allcall' as a direction does not of course work! Transmission will start automatically, and your receive window will open automatically when the transmission starts.

> > callsign% w 48s 160x120 colour
> > callsign% W 192s 320x240 colour
> > callsign% f 256s 640x480 B&W (grey-scale)
> > callsign% v 576s 640x480 colour

> You could use the remote Webcam Command feature to check the weather or security at your holiday home while you are in town; or at your home, while on vacation.

> > Note: Many lap-tops have built-in cameras, and these may or may not work, but either way, they are likely to cause an extra dialog to appear when the camera starts, which makes remote picture taking impossible. The best solution, if you plan to use a laptop, is to use an external USB camera and disable the built-in camera. Most important of all, test the function thoroughly! All the external webcams tested work reliably on desktop computers.

### Webcam Notes

> - External (USB) cameras of most types work reliably here. The DirectShow functions are now used.
> - Clearly, if you wish to point the camera at some specific asset for remote monitoring, a USB camera with tripod mount is best. Consider buying an inexpensive HD camera with built-in lighting and/or night vision capability. The improved picture quality will justify the cost.
> - Cameras built into laptops are less reliable, apparently due to driver limitations, but most should now work using the DirectShow functions.
> - To show your shack or other asset off to best advantage, use an HD webcam, at least 800 x 600 resolution.
> - Images look best if your shack or other asset is well lit. Use high colour temperature lighting. Single sources of light are not ideal.
> - You could use the software COM Port PTT control (which operates the transmitter) to trigger a timer which controls the lighting. First send a 'callsign*' command to check the station is active, and to trigger the lighting, then send the image command.
> - If you don't wish to participate in sharing your webcam with others, uncheck the 'Allow SEND' check box of your Webcam from the Picture/Send Webcam Pic menu item.
> - Remember that the 'Allow SEND' checkbox, when cleared, disables ALL TRANSMISSIONS from the camera, including your own.
> - To encourage others to use your camera, leave a note in your QTC message.

Copyright © Murray Greenman and Con Wassilieff 2013-2016. All rights reserved.