Yep, this is the crux of my question... I don't have much, if any, RF=20
experience so wondering if it's realistic to try to get this to work.
This will be on a field (like a football field), but there will be other=20
objects on the field.  No major buildings etc though.
I want this to be low frequency, and was thinking of the 8xx-900 Mhz=20
range (as I believe 433Mhz is not legal in the US).  I expect the=20
receiving antennas to be relatively large, hence thinking the=20
lightweight moving object would just transmit, and I can do anything=20
necessary on the receivers (I'm expecting 4, but can add more if=20
necessary) to get the data and do the calcs.  Also thinking I can=20
post-process to remove any data points that look off/unrealistic.

Never ever thought of humidity as a factor here... I need to investigate=20
that more.

Cheers,
-Neil



On 10/7/2019 12:01 PM, John J. McDonough wrote:
> With enough receivers, and some pretty fancy software, maybe. RF is=20
> nasty, it gets reflected off everything, the reflections can lead to=20
> one signal arriving over multiple paths, causing interference,=20
> destructive or constructive. Depending on the frequency, lots of=20
> things can absorb RF radiation. Maybe at very low frequencies and=20
> moderate distances you might have some luck, but probably not within a=20
> few feet. In the low MHz range, there aren't a lot of things large=20
> enough to be effective reflectors. Of course, the ionosphere is one=20
> such thing, but the signal strength should be a lot weaker than direct=20
> line of sight so you might make that work. But low frequencies require=20
> large antennas, so I assume you are thinking of Gigahertz or hundreds=20
> of Megahertz. In that case there are plenty of land mines. Buildings,=20
> fences, cars, even airplanes make good reflectors. Leaves are great at=20
> sucking up RF, and when you get into the GHz range, even humidity can=20
> be your enemy. Triangulation is much more likely to be successful, but=20
> even that can be problematic. --McD=20

--=20
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