Roof mount omnidirectional antenna for tracking falcons - what would you do?

[Mike in NM]

Hi guys. I am a falconer, I use a 433 MHz transmitter attached to the falcon for instances where hunts don't go as planned. Generally, the falcon is tracked with a YAGI antenna, but sometimes, when the bird goes real far, it is very useful to track with a roof mounted omnidirectional on the roof of a vehicle.

I'd like to hear opinions and suggestions for putting together such an omni with highest possible gain.

Many thanks!

 

[JimB]

To make an antenna with more gain, you need to make it longer.
433Mhz is the 70cm amateur radio band, I suggest that you investigate ready made antennas made for the amateur market, they should not be too difficult to find.
Also, what are you using for a receiver, are you sure that its sensitivity is a good as possible?

Where are you? I am guessing USA, New Mexico?

JimB

 

[ronv]

I think you trade gain for direction, so if you can't "see" him with the yagi you would need to be much closer with an omnidirectional. Here is a site for a dipole.

Build your own TX antenna for FPV - RC Groups

 

[Mike in NM]

Thanks for the feedback. Jim, the receiver is made by Marshall Radio, a telemetry company and is a well engineered piece of equipment - very low noise and a good company reputation in the industry. I am in New Mexico.

Ron, yes, I do expect to lose sensitivity with the omni, but at least I'll be able to drive toward my mobile target while maintaining contact with the signal. Usually you do this until you are within a mile or so, then get out and use the yagi.

So I should be simply looking at roof mount antennae at 1/4 wavelength? Or is there a better shape/configuration?

 

[JimB]

A 1/4 wave roof mounted antenna would work, but as ronv suggests the gain will be much less than your yagi.

JimB

 

[MikeMl]

Look at AES or **broken link removed**

 

[PatM]

A 5/8 wave WILL give you better performance than a 1/4 wave.
1/4 wave (no gain) compared to a 3db gain 5/8 wave