Amateur Television - A.T.V.

ATV is quite a popular mode of operation in and around the Baltimore and Washington, DC areas.  Many people don't seem to realize that they can use their existing television sets to receive ATV transmissions!  If you haven't experienced ATV yet, try this:

Tune your cable-ready television to cable channel 57 or 60.  Disconnect the cable line from the back of the TV and plug in an outside antenna instead.  You should now be seeing local hams communicating with video!  Of course, these guys and gals need their sleep like the rest of us - so they aren't on the air constantly, but they'll be there for nets, ragchews and other scheduled and un-scheduled time slots.

Another resource you can try are webcams that hams have connected to their ATV stations.  Two buttons are provided below - as well as a button link to the ATV forums area so that you can read about any upcoming ATV events or schedules.

Let's talk a little about ATV.  ATV - or 'fast-scan' television uses the same method of operation an analog  broadcast television station uses.  ATV's primary difference is the different frequency and lower power output - plus the fact that ATV operators talk back-and-forth to each other rather than broadcast constantly.  ATV generally began on the 70cm band since it was the first band that was wide enough to support the 6MHz bandwidth requirement.

Above - typical ATV bandwidth model

ATV Frequency Bands

• 70cm - 420-450MHz

• 33cm - 902-928MHz

• 23cm - 1240-1300MHz

• 13cm - 2390-2450MHz

ATV format uses 525 lines per frame (262.5 lines per field interlaced) at 30 frames per second to create full-motion video.

Above - Interlaced video

Every ham with a technician class or higher license can operate ATV.  The station requirements aren't all that difficult, either.  A good hi-gain antenna (to assure good picture quality), a transmitter (you can buy them complete or build them from a kit), a camera (your home video camera will do), a television receiver (your CATV television or use a downconverter) - and you can be on the air!

In the local Baltimore metro area, you will find ATV operators using voice communication on 144.950MHz and on 147.345MHz in addition to the video signals they transmit.  Local weekly nets for scheduled ATV activity include:

9pm Wednesdays on 147.345 repeater

9pm Thursdays on 147.03 repeater

Above - The WB3LOT station

Above - the WB3LOT video test chart