I have heard and even seen a diagram to allow this to be done. Apparently the basic fax mode is only half duplex. The circuit I saw was a basic hybrid to separate the two wire telephone line into send/receive and to sense when the local fax was sending to trigger the radio (VOX)
There was great interest on it with the emergency communicators, but I don't know as anyone built it. It wasn't much more then a audio transformer and a couple of transistors. -----Original Message----- From: [email protected] [mailto:[EMAIL PROTECTED] On Behalf Of KV9U Sent: Friday, July 28, 2006 4:55 PM To: [email protected] Subject: [digitalradio] Recommendations on FAX A ham about 40 miles away wants to try to make conventional FAX machines work on amateur radio VHF/UHF frequencies. Has anyone tried this and had results that would make it practical? The purpose he envisions, is to be able to send any kind of handwritten notes, such as from medical staff requiring emergency communications. He has considered that it would be operating on full duplex via two bands, e.g., 2 meters/440 and use up to the allowable bandwidth on 2. This would allow for 9k6 bit rates with a 20 KHz signal assuming that a FAX machine has those kinds of tones. I know that other trellis codes may be used and that might not be workable, but I am not sure of the exact tones used by regular telephone FAX machines. I also suggested using Multipsk on HF or VHF and working in simplex, but I have no idea of how well the images would look. A low cost scanner could be used to scan the image and then convert to bmp file format. Even huge files I see will go out in 5 minutes or so. But I have no idea of the quality. Any suggestions on whether this is feasible? 73, Rick, KV9U Need a Digital mode QSO? Connect to Telnet://cluster.dynalias.org Other areas of interest: The MixW Reflector : http://groups.yahoo.com/group/themixwgroup/ DigiPol: http://groups.yahoo.com/group/Digipol (band plan policy discussion) Yahoo! Groups Links Need a Digital mode QSO? Connect to Telnet://cluster.dynalias.org Other areas of interest: The MixW Reflector : http://groups.yahoo.com/group/themixwgroup/ DigiPol: http://groups.yahoo.com/group/Digipol (band plan policy discussion) Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/digitalradio/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
