Re: [EE]:: RF Attenuation in Foliage

The krakenRf is pretty interesting.  Not a pseudo doppler.

On Wed, Mar 11, 2026, 9:22 AM RussellMc <[email protected]> wrote:

> My Stack Exchange answer re RF Attenuation in Foliage
> Properly formatted answer here
> <https://electronics.stackexchange.com/a/766820/3288>
> (https://electronics.stackexchange.com/a/766820/3288)
>
> Also pasted below.
> Main value is (probably) in the two ancient papes 1965 and 1978
> Some other links also of possible interest.
>
> zzzzzzzzzzzzzzzzzz
>
> LORA websearch <https://tinyurl.com/LORARF>
> LORA images with links to web pages here <https://tinyurl.com/LORARF2>
>
> Best frequencies for foliage penetration web search
> <
> https://www.google.com/search?q=what+rf+frequencies+best+penetrate+foliage%3F&rlz=1C1ONGR_enNZ1148NZ1149&oq=what+rf+frequencies+best+penetrate+foliage%3F&gs_lcrp=EgZjaHJvbWUyBggAEEUYOTIHCAEQIRigATIHCAIQIRigATIHCAMQIRigATIHCAQQIRiPAjIHCAUQIRiPAtIBCTExNzQyajBqNKgCALACAQ&sourceid=chrome&ie=UTF-8
> >
>
>
> US military report which is both helpful and confusing - see fig 1 and 2.
> Main useful point is that the lower the frequency the better (probably) the
> results.
> Here
> <
> https://web.archive.org/web/20090524205748/http://stinet.dtic.mil/cgi-bin/GetTRDoc?AD=ADA055391&Location=U2&doc=GetTRDoc.pdf
> >
> 1978!
>
> Older still Here <https://apps.dtic.mil/sti/tr/pdf/AD0648859.pdf> 1965
> report - "The jungle as a communications network" (sounds good :-) ) MAY be
> useful. See fig 1 and 2 .
> "mc/s" in key = MHz.
> A key point is that at short distances 2 MHz is much better than eg 100 MHz
> but as range increases difference decreases.
>
> _________________________________
>
> **hcheung provided these references in a comment**
>
> A Guide to Wildlife Tracking Technologies
> <
> https://wildlifeactinnovations.com/wp-content/uploads/2021/05/A-Guide-to-Wildlife-Tracking-Technologies.pdf
> >
>   -
> 37 pages
>
> History of wildlife tracking technology - wikipedia
> <https://wiki2.org/en/History_of_wildlife_tracking_technology>
>
> Direction finding <https://wiki2.org/en/Direction_finding>  wikipedia
>
> An introduction to directionj finding methodologies
> <
> https://cdn.rohde-schwarz.com/am/us/campaigns_2/a_d/Intro-to-direction-finding-methodologies.pdf
> >
> Rohde & Schwarz - 26 pages
>
> Charts from olde papers.
>
> https://i.sstatic.net/5Kauw6HO.png
> https://i.sstatic.net/Ol8ZGZL1.png
>
> ____  Bad format version of SEEE post  ________________________
>
> Directional aerials are highly desirable - in a fading environment. Signal
> levels may vary with very slight receiver motion, or none at all, due to
> multi-path signals through foliage which mutually interfere.
>
> RSSI tells you signal strength at a point - you need to move to change the
> strength and small distance changes are vanishingly hard to distinguish.
>
> A directional receiver antenna - either scanned mechanically (preferred) or
> based on rover direction, gives you significant directional information
> from a single location, even with a quite broad antenna pattern.
> "For extra points" a steered array antenna would be useful, but the
> complexity and cost probably make a mechanically scanned aerial more
> attractive. At eg 2.4 GHz a 10 dB scanner array is probably realistic.
> Increasingly less so as frequency decreases.
>
> Even at 100's of MHz aerials can be compact enough to make a rotary scanner
> possible with quite a high gain aerial. At say 50 MHz and below antenna
> sizes are liable to be increasingly cumbersome, unless loaded elements are
> used which decrease antenna gain but may have advantages due to lower
> foliage attenuation - see below.
>
>
> As the transmitter is on the target hikers, small transmit aerial sizes are
> desirable.
> If you are using "legal" ISM (Industrial Scientific Medical band)
> frequencies and power levels you may be restricted in regulatory allowed
> transmit power levels. You probably want reduced duty cycle transmit to
> reduce energy use.
> Higher power pulses (maybe a few milliseconds) may allow higher effective
> signal strength. In many administrations the absolute power allowed in the
> 2.4 GHZ band may be substantially higher than in other bands. This, and the
> small aerial size, *may* make 2.4 GHZ more attractive despite higher
> attenuation rates.
>
> If you have not met "LORA" technology have a look.
> LORA provides very long range in adverse conditions for given aerial and
> power, at the expense of data rate.
>
> Start [here](https://tinyurl.com/LORARF).
> And [here](https://tinyurl.com/LORARF2) - every image links to a related
> page.
>
> A rover sounds like an autonomous land vehicle - if so, that would be a far
> greater challenge to build than the RF tracking.
> An aerial drone would be very much more capable - and easier and cheaper.
>
> I mention LORA technology because, regardless of the vegetation answer,
> LORA is reasonably likely to provide a good result for range for a given
> frequency. It uses a complex spread spectrum modulation scheme and has
> "best in class" range capability in adverse conditions. Increasingly good
> results give lower data rates - not an issue here.
> LORA modules are available off the shelf down to the ~ 460 MHZ ISM band.
> Best results are probably achieved with frequencies well below where LORA
> is easily avaiable BUT its characteristics may offset that.
>
> For best frequencies for foliage penetration [start here](
>
> https://www.google.com/search?q=what+rf+frequencies+best+penetrate+foliage%3F&rlz=1C1ONGR_enNZ1148NZ1149&oq=what+rf+frequencies+best+penetrate+foliage%3F&gs_lcrp=EgZjaHJvbWUyBggAEEUYOTIHCAEQIRigATIHCAIQIRigATIHCAMQIRigATIHCAQQIRiPAjIHCAUQIRiPAtIBCTExNzQyajBqNKgCALACAQ&sourceid=chrome&ie=UTF-8
> )
> - there are a number of good looking links.
>
> [Here](
>
> https://web.archive.org/web/20090524205748/http://stinet.dtic.mil/cgi-bin/GetTRDoc?AD=ADA055391&Location=U2&doc=GetTRDoc.pdf
> )
> is a 1978! US military report which is both helpful and confusing - see fig
> 1 and 2. Main useful point is that the lower the frequency the better
> (probably) the results.
>
> See link above for details
>
> [![enter image description here][1]][1]
>
> Older still [this](https://apps.dtic.mil/sti/tr/pdf/AD0648859.pdf) 1965
> report - "The jungle as a communications network" (sounds good :-) ) MAY be
> useful. See fig 1 and 2 .
> "mc/s" in key = MHz.
> A key point is that at short distances 2 MHz is much better than eg 100 MHz
> but as range increases difference decreases.
>
> See link above for details.
>
> [![enter image description here][2]][2]
>
> _________________________________
>
> **hcheung provided these references in a comment**
>
> [A Guide to Wildlife
> Tracking Technologies
> ](
>
> https://wildlifeactinnovations.com/wp-content/uploads/2021/05/A-Guide-to-Wildlife-Tracking-Technologies.pdf
> )
> - 37 pages
>
> [History of wildlife tracking technology - wikipedia](
> https://wiki2.org/en/History_of_wildlife_tracking_technology)
>
> [Direction finding](https://wiki2.org/en/Direction_finding)
>
> **Godjhiyo provided this reference.**
>
> [An Introduction to Direction Finding
> Methodologies - Rohde & Schwarz](
>
> https://cdn.rohde-schwarz.com/am/us/campaigns_2/a_d/Intro-to-direction-finding-methodologies.pdf
> )
> - 26 pages
>
>   [1]: https://i.sstatic.net/5Kauw6HO.png
>   [2]: https://i.sstatic.net/Ol8ZGZL1.png
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