FAX480

Ralph E. Taggart WB8DQT


IMPORTANT NOTE: Most web browsers, including AOL, COMPRESS graphics to reduce the time required to load a page. This compression significantly degrades the quality of the SSTV/FAX80 images on this and other websites. If you want to see such pictures as actually received, you must do two things: (1) Disable the default graphics compression (with AOL this option will be found on the drop-down PREFERENCES menu) and (2) disable caching so you don't simply call up the compressed version of the pictures if you had visited the site previously. In the case of AOL, click on PREFERENCES and then on ADVANCED features and click off the local cache option. Pictures will take longer to load (especially FAX480 images), but this is the only way to see the pictures as they are actually received.


This image, transmitted in FAX480 by Rob, KF7OH, in Yakima, Washington and received by WB8DQT in Michigan shows the quality that can be achieved with a total transmission time of just 2 minutes and 18 seconds! KF7OH was using WinPix Pro and I received the picture using Ver. 3.1 of Pasokon Classic.


What is FAX480?

FAX480 was developed in 1993 (See February, 1993 QST) to provide for relatively high resolution image transmission on HF, VHF, and UHF Amateur Radio bands. FAX480 was designed to bridge the gap between conventional slow scan television (SSTV) and conventional facsimile techniques. While SSTV is becoming increasing popular, it has some very real limitations, including relatively low image resolution. Facsimile (fax) provides the opportunity to transmit images of very high resolution, but it also has its problems. FAX480 was designed to include the best of SSTV and fax technology. Images have four times the resolution of standard SSTV formats, far better immunity to disruption by interference and band conditions, and it will yield far better results for stations that are not operating high power with monster antenna arrays.

The page on Frequently Asked Questions handles common questions with respect to FAX480 and other SSTV modes.

FAX480 Hardware and Software discusses the various SSTV systems that have implemented FAX480 and covers what you will need to get on the air.

As noted above, Technical Standards for FAX480 are presented for use by those developing SSTV hardware or software, to encourage implementation of FAX480 in new systems.

A FAX480 image gallery is included so you can see actual off-the-air images using the FAX480 mode.


Ralph E. Taggart (taggart@msu.edu)