June 2011
Peter, VK3BFG and a handful of others continue to work hard at creating the gadgetry and software, so that all ATVers can access the DiGiTaL Amateur TV repeater. The system is based on German Digital Video Broadcast kits and off the shelf DVB receivers. Uplinks (inputs) are both analog and digital, while the downlink (output) will only be digital DVB-T at 446,500Khz = 446.500Mhz.
There are 2 output channels or streams, VK3RTV1 and VK3RTV2, these Standard Definition (576i) outputs occupy the same bandwidth (7.5Mhz, 442.25 - 449.75) as the old analog TV service.
VK3RTV MUST be transmitting for your Set Top Box or Digital TV receiver to pick up VK3RTV services. You may need to do a "manual" scan or type in the frequency as most receivers skiped over 230 - 470Mhz when using auto-tune/scan. This is assuming your receiver does have a continious RF coverage of 170 to 820Mhz; If not, services may not be receivable.
For retro-grade functionally the analog input frequency has NOT changed and is still on 1250Mhz. The analog FM-TV and Digital DVB-S (satellite standard definition) Inputs operate on a "first in, takes control" basis between the analog and digital inputs for each digital stream RTV1 and RTV2. Meaning there are 4 receivers, 5 when 10.4Ghz is active.
VK3RTV1
Analog input on 1250.25Mhz for FM-TV services.
DiGiTaL input on 1255.50Mhz DVB-S format.
VK3RTV2
Analog input on 1283.25Mhz and 10.41 Ghz for FM-TV services.
DiGiTaL input on 1276.5Mhz DVB-S format.
Operation:
Typically users will be on each channel doing their own thing, sharing the DiGiTaL device without interfering with each other. Viewers just select which channel they want to watch, much like they do for regular TV stations.
The current downlink bandwidth and future technology has the ability to have 4 to 8 SD TV channels. Adding extra channels or other DVB services is not easy, there are lots of ancillary equipment and cables to hookup and controls to duplicate for each TV channel as well as technical and operational issues to work through. So far 1000's of dollars from many sources and hours of Peter's limited time have been spent to get these tv channels operational. This is a first for our small dedicated amateur TV group and may be a first for Australia too. So any criticism on service functionally should be tempered with the knowledge that this is bleeding edge technology for professional TV broadcasters let a lone for a humble group of amateur TV operators. ATV Melbourne is punching well above its weight!
Note on 1283.25Mhz use: This analog input to VK3RTV2 has unknown intermittent interference problem since 2007. Investigations are continuing but the interference makes using 1283Mhz unworkable... 1283.25Mhz FM-TV and 1276.5Mhz DVB-S is primary for operators East of Mt. Dandenong, however, Stations West of Mt. Dandenong (Melbourne metro) with "moderate" power can key up RTV2.
New Touch Tone codes to access the special functions of VK3RTV:
Peter, VK3BFG and a handful of others continue to work hard at creating the gadgetry and software, so that all ATVers can access the DiGiTaL Amateur TV repeater. The system is based on German Digital Video Broadcast kits and off the shelf DVB receivers. Uplinks (inputs) are both analog and digital, while the downlink (output) will only be digital DVB-T at 446,500Khz = 446.500Mhz.
There are 2 output channels or streams, VK3RTV1 and VK3RTV2, these Standard Definition (576i) outputs occupy the same bandwidth (7.5Mhz, 442.25 - 449.75) as the old analog TV service.
VK3RTV MUST be transmitting for your Set Top Box or Digital TV receiver to pick up VK3RTV services. You may need to do a "manual" scan or type in the frequency as most receivers skiped over 230 - 470Mhz when using auto-tune/scan. This is assuming your receiver does have a continious RF coverage of 170 to 820Mhz; If not, services may not be receivable.
For retro-grade functionally the analog input frequency has NOT changed and is still on 1250Mhz. The analog FM-TV and Digital DVB-S (satellite standard definition) Inputs operate on a "first in, takes control" basis between the analog and digital inputs for each digital stream RTV1 and RTV2. Meaning there are 4 receivers, 5 when 10.4Ghz is active.
VK3RTV1
Analog input on 1250.25Mhz for FM-TV services.
DiGiTaL input on 1255.50Mhz DVB-S format.
VK3RTV2
Analog input on 1283.25Mhz and 10.41 Ghz for FM-TV services.
DiGiTaL input on 1276.5Mhz DVB-S format.
Operation:
Typically users will be on each channel doing their own thing, sharing the DiGiTaL device without interfering with each other. Viewers just select which channel they want to watch, much like they do for regular TV stations.
The current downlink bandwidth and future technology has the ability to have 4 to 8 SD TV channels. Adding extra channels or other DVB services is not easy, there are lots of ancillary equipment and cables to hookup and controls to duplicate for each TV channel as well as technical and operational issues to work through. So far 1000's of dollars from many sources and hours of Peter's limited time have been spent to get these tv channels operational. This is a first for our small dedicated amateur TV group and may be a first for Australia too. So any criticism on service functionally should be tempered with the knowledge that this is bleeding edge technology for professional TV broadcasters let a lone for a humble group of amateur TV operators. ATV Melbourne is punching well above its weight!
Note on 1283.25Mhz use: This analog input to VK3RTV2 has unknown intermittent interference problem since 2007. Investigations are continuing but the interference makes using 1283Mhz unworkable... 1283.25Mhz FM-TV and 1276.5Mhz DVB-S is primary for operators East of Mt. Dandenong, however, Stations West of Mt. Dandenong (Melbourne metro) with "moderate" power can key up RTV2.
New Touch Tone codes to access the special functions of VK3RTV:
Existing Codes (Circa 2011)
..TT4.. = *4# Reset - return to receive
TT0.TT1 = *01# Colour Bar and Tone
TT0.TT2 = *02# Colour Bar No Tone
TT0.TT3 = *03# Analog Right Audio Channel on
TT1.TT0 = *10# Beacon Mode
TT1.TT1 = *11# Digital Signal Report
TT1.TT2 = *12# spare for future use
TT1.TT3 = *13# Analogue Signal Report
TT2.TT0 = *20# VK3RTV Shack Camera
TT2.TT1 = *21# spare for future use
TT2.TT2 = *22# Digital Receiver Exit (clear OSD)
