VK3KHB

Amateur TV capable
Set Top Box / DTV receivers

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Welcome,
Not all DVB-T DiGiTaL TV receivers can tune in to the 70cm amateur television service (440-450Mhz) but the below list can. These receivers have been tested by aTV users and found to work well with the VK3RTV DVB-T repeater on Mt. Dandenong in Melbourne, Australia. Some receivers are a bit deaf and need a signal boost, by way of an RF amplifier or dedicated antenna. Units with a receive signal figure of -70dBm or better will work on most domestic TV setups, they work well when the unit is the only DTV receiver connected to the antenna, (no splitters / multiple outlets). Also note that DTV receivers are quickly superceeded by newer models or different revisions of the same model and the aTV capability may not be available in earlier or later versions of makes or models listed here... Sorry it seems to be the nature of manufacturers to make "changes without notice".

To check if your DTV receiver can tune aTV signals you'll need a quailty high gain UHF antenna pointing at the amateur TV service, use quality coax cable and connectors as aTV signals are at a low power level, you'll need as much signal gain as you can muster.

ATV signals are just outside of the normal TV bands of your DTV receiver and may be a bit deaf, so the more signal you get the better your chances of receiving the service. Unfortunately you'll also need to know if a signal is being transmitted for your receiver to tune in and store the service. In most capital cities there is usually someone is on after 8pm but not always and you may need to contact your local Amateur Radio Club for more details.

Tuning Notes: ATV has no assigned TV channel number; so a scan by channel number will not work. Only a scan by frequency (446.500Mhz) may work. Also some DTV receivers see this frequency as Ch 350, 900 or some other special number, a signal MUST be there for the DTV receiver to tune in and store the channel.

Tuning analog ATV is only slightly better, still has all the same problems as mentioned above.

Choosing DTV receivers for aTV reception based on specification is difficult:
We have discovered that manufacturer specifications do not always reflect the actual specification limits, especially for "out of band" (ie. aTV) frequencies or stated signal sensitivities. Some of the devices above are not rated to receive aTV frequencies yet do, while other imply they can but don't. If you can key in a frequency to your DTV try it as it may work for you.

The "Masthead Preamplifier" is optional.
For Melbourne the ATV repeater is at Mt.Dandenong.

Starting out:
The simplest way to receive ATV is by setting up a receive system. If you have a "Free to Air" television receiving system, you already have all that you need. If you have a Cable TV system then you will need to install an external UHF antenna which needs to point at "Free To Air" TV station transmitters. In Melbourne Mt. Dandenong is the main TV transmission site for commercial, government and aTV services.

All TV antenna have a frequency response:
for Analogue services it starts at 50-150, 150-300, 470-800Mhz.
for DiGiTaL services it starts at 150-300 and 470-800Mhz
ATV occupies 440-450Mhz just out of design range but still receivable.

Receive but poorly?
As DiGiTaL is a series of sub-carriers (signals) in a 7Mhz wide TV channel, these all need to be at a consistant level. If levels are uneven the received picture may not be decoded correctly and a jumpy, blocky picture or intermittent sound or worse "no signal" condition may result. One reason why that old TV antenna may not be suitable.

Click here for more infomation on how to receive ATV pictures

73's for now.
Gary, VK3KHB