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Tx Antenna mod

Posted by Tim McMahan on May 6, 2010 at 11:30am

I was perusing online stores yesterday, when I found several flat panel 2.4ghz antennas in the 15 dollar price range.  Coulld one of these be used on a Tx to extend range?  I mean, they have the nice ones, with a very tight beam, but then Ii'd have to really get a good bead on the plane.  Would one of these cheapies give me some gain by just facing the same direction as the plane?  I figure i do that anyways.

 

Just a thought,

Tim

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Replies

  • Lew Payne May 10, 2010 at 5:11pm
    In case anyone's interested, here's a simple to construct, 17dB gain, 2.4GHz quad antenna. Here's the same thing for 1.2GHz. Here's a whole series of antenna designs from the same source (W1HBQ).
  • Tim McMahan May 7, 2010 at 5:40am
    Ok, Lew,
    you confirmed what I was HOPING to be accurate thought. That yes, at short range most antennas aren't THAT directional, so I point in the general direction and BAM, safely increased range. After all I wouldn't want to do anything imprudent and jepoardize the craft or surrounding properties, people, etc.

    Thanks,
    Tim

    Martin,
    I promise, pointing out stuff like the coolness factor is TOTALLY WELCOME in any thread of mine, though it may be shunned by some folks here. I have argued for many years, that if necessity if is the "mother of invention", then laziness is the father, and coolness is the mistress. When Da Vinci invented the elevator to go up and down the cliffs to the beach to do oceanfront work, I don't think necessity was involved. It was one of 2 things. 1- Didn't feel like taking the stair, or 2- frikkin' COOL!! LOL! Rock on my friend, rock on. I might get the big clunky aluminum 15 element beam now! LOL!

    Thanks.
    Tim
  • Lew Payne May 6, 2010 at 9:58pm
    As Martin Seven pointed out, all these antennas have a characteristic lobe pattern. That lobe is wide enough where "exact" aim is not necessary. I've noticed that many folks implement pan/tilt on their antenna tracking system, and I have yet to understand why they feel they need tilt control (moving the antenna vector up/down). An antenna that's pointing 15 to 20 degrees up from level ground is good enough, period... at the distances and wavelengths we're talking about here. Likewise, it's only necessary to pan (left to right) the antenna in the general direction of the craft. In addition, at close distances, the vertical lobe overlaps the horizontal so much that there's no need to turn the antenna when the craft is behind it and close by. The attenuation point behind the antenna is not very null, until you start moving away from it. From one amateur radio operator to another.
  • Moderator
    Sgt Ric May 6, 2010 at 11:58am
    I don't know about "cheapies", but patch antennas are a common mod to increase range.

    I have added one to my Futaba TX and as usual have one for my 900mhz video RX.

    That price is alot cheaper than most, so I wonder about quality and performance, but as we see alot these days, those are not always connected.
  • Overwatch May 6, 2010 at 11:52am
    Of course it would, just make sure the impedances match (antenna's Ω and the TX's Ω should be the same). Also consider the possible issues with reliability - a narrower beam means it's easy to loose the link (and a plane). Always have a backup :)
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