UAV link range extension

Lew Payne June 6, 2010 at 8:09am

I notice that you really like to remain vague, and not give any information which would "lock down" your answers (and thus subject them to public scrutiny). This will be the last post I'm making in this thread, for obvious reasons. Antenna losses of the type we're talking about can be quantified using the Polarization Loss Factor (PLF). Since you did not state what type of antenna (wavelength and design) you are using on the UAV, I'm unable to complete the formula. Suffice it to say that you are experiencing at least 3 dB loss from polarization issues alone, which is the equivalent of cutting your transmit power in half.

What you term "efficient results" is what I call "lack of understanding of antenna theory."

Polarization Loss Formula.jpg

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Morli June 6, 2010 at 7:38am

Fahad,
can you pls post the link to your antenna and tx module? I am curious about "antenna is 17 dB" as to how/where you got that number. Thanks

Lew Payne June 2, 2010 at 6:16pm

One note of curiosity... since you're using a helical antenna at the ground station end, and since helical antennas come in either LHCP (left-hand circular polarization) or RHCP (right-hand circular polarization) depending on which direction their helix is wound... and since you're not using a helical antenna on the UAV... how are you mitigating the losses from receiving and transmitting with different (or no) polarizations (since both ends of the link must use the same polarization)?

Lew Payne June 2, 2010 at 11:56am

Helical antennas were invented in the 1940's by John Kraus (W8JK). Is there anything substantially different in your design that makes it stand out when compared to the standard helical antennas that have been developed over the years (see this link)? If not, perhaps you should consider publishing a construction article rather than a research paper. Since you don't really seem to be very forthcoming in your responses, I'll assume you have not yet discovered something that violates the laws of physics.

Lew Payne June 1, 2010 at 11:13pm

UAV wireless links can take place on several different bands; which band are you referring to, in particular? Also, as you already know, the UAV as well as the ground station requires an antenna; which are you referring to, in particular? To obtain 17 dBm gain at 900MHz would require an antenna a bit larger than most FunJets can carry. One final thing... what testing methodology did you use in order to determine that your particular design provides 17dBm gain? Do you have a diagram showing the major and minor gain lobes, from both the vertical and horizontal planes? If not, how are you able to make this claim?

Taylor Cox June 1, 2010 at 9:38pm

Are you talking about an antenna for the xbee communication modules?

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