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awizardalso

Possible to modify wire antenna into.....?

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Greetings,

I've been bitten by the bug and having limited financial resources, I must be content to hang an inexpensive wireless camera under a 4 foot blimp. I bought the camera off eBay for next to nothing and works reasonably well out to at least 300 feet. Reception is dependent on the orientation between the antennas, and is intermittent during flight. It's basically a 1" cube with a 3-1/2" wire antenna. I've disassembled the camera and discovered that the camera and transmitter can be separated into two parts. The transmitter is a small PC board about 1/2 by 1/4 inch with the antenna wire soldered into the center.

My question is, would it be possible to mount the entire transmitter/antenna package into a waveguide to achieve directional characteristics? This could be 'aimed' off the mooring line back to the receiver, with it's similarly aimed antenna. Due to the vicinity of high voltage power lines, any thought of a wired camera is out.

The transmitter operates around 1100 MHz. The wire antenna is 92mm, which doesn't add up to anything in relation to the frequency of operation. A quarter wave at 1100 MHz would be about 68mm, by my calculation. I assume this antenna operates like a walkie-talkie antenna which is just one part of a tuned network.

I'd appreciate any thoughts on the feasibility of this. My previous experience with antennas are in the 11m CB and more recently 2m amateur bands. Wave guides are a whole new breed of animal. I've seen several home brewed versions, including one where a 1/4 wave piece of wire soldered to a coax connector and mounted into the side of an olive can from a pizza shop, no less! I'm at a loss about the odd relationship between the length of this antenna and the operating frequency, and how this would figure into the dimensions for a wave guide. Thanks for ANY input.

Mike (kc8flu)

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I've disassembled the camera and discovered that the camera and transmitter can be separated into two parts.

Have you seen this article?: http://www.rc-cam.com/hk_video.htm

The transmitter operates around 1100 MHz. The wire antenna is 92mm, which doesn't add up to anything in relation to the frequency of operation. A quarter wave at 1100 MHz would be about 68mm, by my calculation.

It would be about 65mm at 1100Mhz. If it is just a hunk of wire, then the vendor cut it wrong (off by a mile). That is typical of the quality of the Hong Kong systems.

I suggest you make a ground plane antenna for your band. Here are the details to Yb2normal's 2.4Ghz version. Just rescale it for your 1.1Ghz operation: http://www.yb2normal.com/antenna3.html

My question is, would it be possible to mount the entire transmitter/antenna package into a waveguide to achieve directional characteristics? This could be 'aimed' off the mooring line back to the receiver, with it's similarly aimed antenna.

It would be more practical to install a patch on the Tx. However, I think that the best thing to do would be to use the ground plane design on the Tx and a good patch on the Rx.

Patch design: http://www.rc-cam.com/gp_patch.htm

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