June 16, 2005
Amateur Television, ATV, was presented at the June 16 meeting of the Ames Amateur Radio Club. Michael Wright (K6MFW) demonstrated ATV transmission, reception, and use of ATV equipment. Following is what was presented but this site has additional material.
ATV is not
SSTV and HDSSTV are subsets of ATV
Television: The transmission of visual images of moving and stationary objects, generally with accompanying sound, as electromagnetic waves and the reconversion of received waves into visual images.
Transmission mode: NTSC standard: composite video signal with refresh rate of 60 half-frames per second (interlaced). Each frame contains 525 lines and 16 million different colors.
Same mode used by regular TV sets. Hams also call this fastscan TV (FSTV).
Comparison of Amateur TV with Broadcast TV
|Subject||Amateur (FCC Part 97)|
Not compensated for services
|Broadcast (FCC Part 73)
Compensated for services
|Typical Players:||Individual hams such as W2NYC, KK1CW, KK6MX, KT6LN, WB6RIY, WA6HNE, KN6PE and ATV clubs such as K6BEN||KRON, KPIX, KQED, CNN, FOX, NBC, CBS, ABC, PBS and various media moguls|
|Transmission Mode:||NTSC (fastscan)||NTSC (fastscan)|
|Bandwidth:||6 MHz (video at 1.25, audio 4.5 from video)||6 MHz (video at 1.25, audio 4.5 from video)|
|Receiving unit:||Consumer type TV set||Consumer type TV set|
|RF equipment:||100mW to 30W transmitter||500W to 5000W transmitter|
|Antenna:||Yagi, J-pole or collinear on mast or tower as high as the ham can afford, hillside or mountain top from a friend.||Gillion dollar high ERP antenna on 100 to 2000 ft towers on mountain tops.|
|Camera equipment:||Camcorder or whatever they can afford.||Broadcast quality studio cams with expensive lenses, $60,000 shoulder DV-cams|
|Studio equipment:||A room in a house, a video cable between camera and transmitter. A extra light in the room. Maybe a video titlemaker.||Large stage, array of stage lights, control room, glamour talking heads, props, armies of technicians and engineers, lots of expensive equipment.|
|Portable equipment:||What the ham can carry or put in their car, operates on amateur radio frequencies||Mobile van equipped with $2 million worth of shoulder cams, processing equipment, powerful microwave uplink transmitter, telescopic mast. Also includes $2 million helicopter with $2 million worth of transmission equipment. Operates on private frequencies.|
|Cost to get started:||Price of camera, price of TV set, $150 - $350 for ATV transmitter, $10 - $250 for antenna, $50 - $200 for cable.||If you have to ask, you cannot afford it.|
|Licensing:||All classes of amateur radio license (pass written test, $14 fee)||File tons of paperwork for justification and coordination, get commercial sponsorship, fees can be hundreds of thousands and perhaps millions of dollars.|
|Programs to be aired:||Chat with friends, show-and-tell latest radio gear, vacation photos, ARES/RACES events, and public service events at NO CHARGE and NO FEES.*||Sports, entertainment, news, movies, commercials, paid programs.|
* In this context Amateur is a legal term meaning compensation free, it does not mean beginner. This is why it is against FCC regulations to earn money or conduct business on ham radio frequencies.
Dont do sports and entertainment like commercial TV broadcasting and or charge people for your services. Other restrictions apply such as indecent, libel, scandelous, and other material prohibited by the FCC.
Q: Why does cable TV have more channels than what the FCC allocates in the RF spectrum?
A: Cable TV uses frequencies of other radio services in addition to FCC allocations.
This is OK as long as the signal stays contained in the cable!
A sample of frequency allocations for TV channels:
A more comprehensive listing is here.
-------- Broadcast TV -------- --------- Cable TV ----------- CH BAND VIDEO AUDIO CH BAND VIDEO AUDIO 2 54- 60 55.25 59.75 2 54- 60 55.25 59.75 3 60- 66 61.25 65.75 3 60- 66 61.25 65.75 4 66- 72 67.25 71.75 4 66- 72 67.25 71.75 14 470-476 471.25 475.75 14 120-126 121.25 125.75 15 476-482 477.25 481.75 15 126-132 127.25 131.75 57 728-734 729.25 733.75 57 420-426 421.25 425.75 58 734-740 735.25 739.75 58 426-432 427.25 431.75 59 740-746 741.25 745.75 59 432-438 433.25 437.75 60 746-752 747.25 751.75 60 438-444 439.25 443.75 82 cellphones and 2-way radios 82 570-576 571.25 575.75 83 cellphones and 2-way radios 83 576-582 577.25 581.75 84 none 84 582-588 583.25 587.75 85 none 85 588-594 589.25 593.75
UHF, 440 MHz:
1.2GHz and 2.4GHz:
Connect vertically polarized antenna to cable ready TV set, aim antenna towards Mt. Hamilton (or east San Jose foothills).
Connect vertically polarized antenna to cable ready TV set, aim antenna towards Mt. Diablo (Contra Costa County).
Connect 2.4GHz antenna to 2.4GHz receiver (can also use lowcost X-10 wireless video receivers), aim antenna towards Stanford University in Palo Alto.
With the upcoming STS-114 flight, we have been working on means for the Ames Amateur Radio Club (AARC) to re-transmit NASA TV on the K6BEN amateur television (ATV) video repeater. For more on ATV evaluation, click here.
ATV was demonstrated at last years Moffett Airshow in 2004. Below are visitors viewing ATV at the Ames Amateur Radio Club exhibit. The other picture are some videocaptures of actual ATV transmissions from the club exhibit through the K6BEN repeater (VCR recorded reception in another part of the bay area) Click for more photos of the AARC exhibit at the airshow.