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Stupid tech question: need a small TV antenna

Old 08-19-05, 10:34 AM
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Stupid tech question: need a small TV antenna

I just bought a nifty PCMCIA TV tuner card. It looks like it works great - decent and non-bloaty software, decent video quality, recording capabilities.

Only one problem: I intend to use this when I'm sitting at a coffee shop, but the card doesn't come with an air antenna, so I can't get any reception. It has a coaxial input, so I need a coaxial VHF air antenna small enough to carry around in my tech bag - 5" or less would be ideal. Sounds bizarre, but I can't find one - I've spent over an hour looking for one, and all I can find are huge, roof-mounted antennas for home theater systems. My best idea is to buy an antenna designed for a WiFi card - thinking that, hey, an antenna is an antenna - but my electronics sk1llz aren't strong enough to rely on this presumption.

Hate to resort to this forum for such a dumb request, but can anyone help me out?

- David Stein
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Old 08-19-05, 11:08 AM
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is it hdtv
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Old 08-19-05, 11:31 AM
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Originally Posted by raven56706
is it hdtv
Can be, I think, but I really don't care. This is for a tiny TV applet that will run at a much-reduced size in the corner of my display while I type up some notes.

- David Stein
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Old 08-19-05, 11:36 AM
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Man, I can see your pain in searching for this. The easy answer was going to be, if you wanted HD, that a small antenna won't cut it, unless your office is under the antenna.

Looks like there is an untapped niche market for a small antenna that would clip/velcro to a laptop case, but not crack/bend in a laptop bag.
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Old 08-19-05, 11:38 AM
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I think you're going to have some trouble with this.

Coax is 75 ohms, wired TV antennas are 300 ohms. So you may need something like an indoor wire antenna and a 300 to 75 ohm converter.

Converter: http://www.radioshack.com/product.as...t%5Fid=15-1253

Antenna: http://www.radioshack.com/product.as...5Fid=42%2D2385
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Old 08-19-05, 11:58 AM
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What brand did you get? Ive been looking for one for a little bit now. I see some for sale on Ebay, that come with a small antenna. Im looking for something to watch football while I am at work on my laptop. It doesnt need to be HD. Plus, how is the video input?
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Old 08-19-05, 12:22 PM
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This may look dorky but here's an all-in-one solution.

http://www.mobilevideozone.com/produ...A-636D53825D07

They have some others you might want to look at too.

http://www.mobilevideozone.com/produ...oduct_type=800
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Old 08-19-05, 02:11 PM
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Originally Posted by sfsdfd
It has a coaxial input, so I need a coaxial VHF air antenna small enough to carry around in my tech bag - 5" or less would be ideal. Sounds bizarre, but I can't find one...
There's actually a very good reason for this: Small antennas don't work. They just don't. You can't violate the laws of physics.

All conductors are antennas. They receive energy from radio waves and this induces a current flow along the length of the antenna. The idea behind an actual "antenna" is to make one or more conductors such that the currents they receive are in sync with each other (constructive interference), thus giving you a signal that is high enough above the background noise for your tuner to be able to see the signal and ignore the noise. In order to do that, you need to have the conductor pick up the radio waves you want it to pick up and try to ignore the rest. The main thing that controls this is the length of the antenna.

The basic unit of antenna length is the dipole. The dipole is half the wavelength of the frequency you want to receive. For TV channels, this varies between 7 inches (for the upper end of UHF) to 102 inches (for channel 2). If the signal is strong enough, yes, any conductor can pick it up pretty good, but usually TV signals aren't all that strong anymore, so you need a good antenna to pick anything good up.

Anyway, you're probably screwed. You might find a small antenna, but it will not work well, if at all. Sorry. Your best bet is to find a set of rabbit ears that can shrink down very small, so that you can expand them very large wherever you are.

Edit: And no, a 2.4 Ghz antenna won't work. TV channels are in the Mhz range, not the Ghz range.
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Old 08-21-05, 02:54 PM
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What Otto said about frequency and length is correct.

If you have a digital tuner, you can tune the new "digital" frequencies assigned to all the stations, which are UHF, and physically a smaller antenna.

There is a small UHF antenna (indoor) called "Silver Sensor" which some swear by, some swear at. I don't have one, but it might be your best bet. It is directional and your turn by hand to aim at tower. You probably only get 15-20 mile range tops.
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Old 08-21-05, 08:24 PM
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I used to have a handheld short wave scanner with a 'rubber duckie' antenna. It worked with audio from up to 1.2 Ghz. Would something like that work for video?
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Old 08-26-05, 12:50 PM
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Thanks for the advice, guys. I have been watching this thread, just haven't had a chance to respond 'til now.

Otto/OldDude: Your comments about reception and length make sense. So instead of looking for a short antenna, I started looking for a telescoping one - e.g., portable TV antennas. It took a while to wade through unworkable matches (most seem to have dipole connectors instead of coax), but I found one that will probably work. If it does, I'll post a link here next week to the antenna with comments about the overall result.

- David Stein
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