RE: [digitalradio] Recommendations on FAX
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: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of KV9U Sent: Friday, July 28, 2006 4:55 PM To: digitalradio@yahoogroups.com 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/
Re: [digitalradio] Recommendations on FAX
At 09:55 PM 7/28/2006, KV9U wrote: A low cost scanner could be used to scan the image and then convert to bmp file format. Any suggestions on whether this is feasible? Scanning the image sounds like a good idea. The image could be converted from .bmp to .jp2 and sent using HamPal or DigTRX. 73, Mark N5RFX 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/
Re: [digitalradio] Recommendations on FAX
Are you able to put your hands on the info by chance? Howard W6IDS Richmond, IN - Original Message - From: RussellHltn [EMAIL PROTECTED] To: digitalradio@yahoogroups.com Sent: Sunday, July 30, 2006 3:42 AM Subject: RE: [digitalradio] Recommendations on FAX 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) 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/
RE: [digitalradio] Recommendations on FAX
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 is a good discussion of facsimile theory at http://electronics.howstuffworks.com/framed.htm?parent=fax-machine.htmurl=http://home.maine.rr.com/randylinscott/fax.htm The communication between two fax machines is outlined a little more than 3/4 of the way down the page. It appears to be full duplex. 73, Mark N5RFX 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/
Re: [digitalradio] Recommendations on FAX
Are you able to put your hands on the info by chance? HAL has a system that allows fax over radio: http://www.halcomm.com/docs/fax4100.pdf 73, Mark N5RFX 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/
Re: [digitalradio] Recommendations on FAX
Yes, I was aware of the HAL modem, but each one is around $1500 so unlikely to be purchased. It would mostly be used for HF. It uses Clover II and Clover 2000 which has a pseudo full duplex characteristic and I can see how this would be useful for a handshaking requirement. The individual wanting to do this, is primarily interested in running two bands (e.g., 2 meters/440) with full duplex. 73, Rick, KV9U Mark Miller wrote: Are you able to put your hands on the info by chance? HAL has a system that allows fax over radio: http://www.halcomm.com/docs/fax4100.pdf 73, Mark N5RFX 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/
Re: [digitalradio] Recommendations on FAX
I don't know if the info you seek is here but Try this website for info: http://www.hffax.de/ Brad N1NPK [Non-text portions of this message have been removed] 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/
Re: [digitalradio] Recommendations on FAX
The individual wanting to do this, is primarily interested in running two bands (e.g., 2 meters/440) with full duplex. Well if it was absolutely necessary to use telephone fax machines, then at the originating end you would need a device that supplies -48 volts to the fax machine telephone interface, and can sense when the originating fax machine goes off hook. This device would then key the transmitter. At the answering end, a device would have to sense when the receiver breaks squelch and would have to provide the 20 Hz ring signal to the answering fax machine, sense off-hook, and key the transmitter.. When the fax is completed the originating end would go on-hook and the originating device would have to de-key the transmitter. At the answering end, the device would sense squelch, go on-hook and de-key the transmitter. A start would be the device like http://www.jkaudio.com/tap-1.htm with the addition of the transmitter and receiver control circuitry. A good article on telephone interfacing is at http://www.tkk.fi/Misc/Electronics/circuits/teleinterface.html#audioint This sounds like an interesting project, however there are programs set up to send high quality digital images, ie WinDRM, HamPal, and DigTRX. 73, Mark N5RFX 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/
Re: [digitalradio] Recommendations on FAX
Great information. However, the ham that contacted me has asked me to not give him any more information as he only wants to do it his way or nothing apparently. You would think that you would have a ham who would be greatly interested in digital comx, especially for HF since the distances he wants to cover do not seem very practical to me on VHF. But he only wants to believe he is doing analog and specially doesn't want digital stuff. Rick Mark Miller wrote: The individual wanting to do this, is primarily interested in running two bands (e.g., 2 meters/440) with full duplex. Well if it was absolutely necessary to use telephone fax machines, then at the originating end you would need a device that supplies -48 volts to the fax machine telephone interface, and can sense when the originating fax machine goes off hook. This device would then key the transmitter. At the answering end, a device would have to sense when the receiver breaks squelch and would have to provide the 20 Hz ring signal to the answering fax machine, sense off-hook, and key the transmitter.. When the fax is completed the originating end would go on-hook and the originating device would have to de-key the transmitter. At the answering end, the device would sense squelch, go on-hook and de-key the transmitter. A start would be the device like http://www.jkaudio.com/tap-1.htm with the addition of the transmitter and receiver control circuitry. A good article on telephone interfacing is at http://www.tkk.fi/Misc/Electronics/circuits/teleinterface.html#audioint This sounds like an interesting project, however there are programs set up to send high quality digital images, ie WinDRM, HamPal, and DigTRX. 73, Mark N5RFX 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/
Re: [digitalradio] Recommendations on FAX
Hi Rick and the group just a pennies worth 1) you might consider using fractal image compression schemes (currently used in spy satelites to save time, power, and bandwidth. hunt up a copy of *Fractals Everywhere*http://www.amazon.com/gp/product/sitb-next/0120790610/104-8579362-6464706?redirect=trueby michael f. Barnsley for a discussion of the mathmatics involved. I suspect the theory could be applied to any transmission mode and need not be limited to x-25 or 802.11b-g. On 7/29/06, KV9U [EMAIL PROTECTED] wrote: 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 [Non-text portions of this message have been removed] 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/
