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Remove Radio Occlusion?

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The radio occlusion is completely unrealistic. Why do I think this?   With my cheap ass Walmart walkie talkies, I can talk to my buddy half a mile away being in two different valleys just fine.  However, often times just being prone in grass can prevent people from coms who can see each other.  Can somebody explain how this is realistic?  And if it isn't realistic.. then why do we use it?

 

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Dude I was using a 117 equivalent trying to talk to someone in the next room using a 117 equivalent but couldn't because the door was closed. We could have just shouted through the door and heard each other. Radio occlusion is real and radios are very temperamental. Your experiences may vary. This was real life by the way.

Edited by OriginalPancake

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Can confirm. had 119 Went prone. Could not talk to Strykers 500m away. Grabbed antenna and pointed it up. Could talk to Strykers. Had dude with 148 prone couldn't talk to other squad, i walked up to him, pointed his antenna up, he could then talk to squad leader 100m behind us.

What is fun is when you add freq hop and crypto, it cuts the radio range in half ish.

 

Was at base of hill, could not talk to other people on other side of hill but could hear them. They were farther from the hill. I had to climb the hill to talk to them. RADIOS FUCKING BLOW.

Edited by WA Lancer

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Bowman. Vehicle electric assisted, 8+foot long antennae, on a rack radio on steroids. Lost comms with a vehicle 250 meters away because there was a thick as fuck breezeblock house on a mild rise in between us. My vehicle commander got fucking roasted by PSG for not responding on comms.
 

 

 

Shit happens, it's worse IRL. The only benefit irl is that it's easier to wiggle an antennae, 'cause standing up is the only way you can do it in Arma. Also RF burns.

Edited by JakCurse

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The radio occlusion is completely unrealistic. Why do I think this?   With my cheap ass Walmart walkie talkies, I can talk to my buddy half a mile away being in two different valleys just fine.  However, often times just being prone in grass can prevent people from coms who can see each other.  Can somebody explain how this is realistic?  And if it isn't realistic.. then why do we use it?

 

Signal path loss basics
The signal path loss is essentially the reduction in power density of an electromagnetic wave or signal as it propagates through the environment in which it is travelling.
 
There are many reasons for the radio path loss that may occur:
 
  • Free space loss:   The free space loss occurs as the signal travels through space without any other effects attenuating the signal it will still diminish as it spreads out. This can be thought of as the radio communications signal spreading out as an ever increasing sphere. As the signal has to cover a wider area, conservation of energy tells us that the energy in any given area will reduce as the area covered becomes larger. This effect is also dependent on the frequency of the carrier the higher the carrier fq the more free space losses degrade the signal over time.

 

  • Absorption losses:   Absorption losses occur if the radio signal passes into a medium which is not totally transparent to radio signals. This can be likened to a light signal passing through transparent glass. At higher fq the air itself will attenuate the carrier.

 

  • Diffraction:   Diffraction losses occur when an object appears in the path. The signal can diffract around the object, but losses occur. The loss is higher the more rounded the object. Radio signals tend to diffract better around sharp edges.

 

  • Multipath:   In a real terrestrial environment, signals will be reflected and they will reach the receiver via a number of different paths. These signals may add or subtract from each other depending upon the relative phases of the signals. If the receiver is moved the scenario will change and the overall received signal will be found vary with position. Mobile receivers (e.g. cellular telecommunications phones) will be subject to this effect which is known as Rayleigh fading.

 

  • Terrain:   The terrain over which signals travel will have a significant effect on the signal. Obviously hills which obstruct the path will considerably attenuate the signal, often making reception impossible. Additionally at low frequencies the composition of the earth will have a marked effect. For example on the Long Wave band, it is found that signals travel best over more conductive terrain, e.g. sea paths or over areas that are marshy or damp. Dry sandy terrain gives higher levels of attenuation.

 

  • Buildings and vegetation:   For mobile applications, buildings and other obstructions including vegetation have a marked effect. Not only will buildings reflect radio signals, they will also absorb them. Cellular communications are often significantly impaired within buildings. Trees and foliage can attenuate radio signals, particularly when wet.

 

  • Atmosphere:   The atmosphere can affect radio signal paths. At lower frequencies, especially below 30 - 50MHz, the ionosphere has a significant effect, reflecting (or more correctly refracting) them back to Earth. At frequencies above 50 MHz and more the troposphere has a major effect, refracting the signals back to earth as a result of changing refractive index. For UHF broadcast this can extend coverage to approximately a third beyond the horizon.

 

  • Phase cancellation occurs when two signals of the same frequency are out of phase with each other resulting in a net reduction in the overall level of the combined signal. If two identical signals are 100% or 180 degrees out of phase they will completely cancel one another if combined.
These reasons represent some of the major elements causing signal path loss for any radio system.
 
The most complaints we get are about the 343
 
AN/PRC-343 (H4855)
The AN/PRC-343 (NSN 5820-99-721-8335) Personal Role Radio (PRR) is a compact and lightweight short-range communication transceiver set.  This radio set utilizes advanced wireless LAN technology, incorporating spread spectrum techniques at 2.4 GHz, ensuring that the system has a low probability of interception and detection and is designed to perform in dense electromagnetic environment.  The radio transmissions utilize a proprietary form of Direct Sequence Spread Spectrum which, to an eavesdropper, will appear like noise.
 
Specifications:
Frequency Coverage: 2,400 - 2483 MHz, 256 Channels available
Modulation: QPSK (Direct Sequence Spread Spectrum)
Voice Coding: CVSD
Data Protocol: Modified IEEE 802.11
RF Power Output: 100 mW
Range: 500 meters (Rural Terrain) transmission through up to three floors (Urban Terrain)
Power Requirements: 2 AA primary cells provide typically 24 hour use (1:7:16 Tx/Rx/S’BY Ratio)
Weighs: 1.5 kg
Microphone: Electret Noise Canceling
Respirator: NBC Compatible
Ear Piece: Custom Molded design
Compatibility: VHF Combat Radio, UHF Combat Radio, HF Combat Radio
Hands-Free Operation: 435 MHz wireless operation
128 Bit Unique Coding
Simple Code Learn Mode
 
 
 
With an operating fq of 2.4 GHz the 343 is much more susceptible to free-space losses along with being less readily diffracted and very unlikely to refract as they will be absorbed by the D layer of the ionosphere. Additionally with an PEP of 100mw from the transmitter and reported antenna having a gain of 3.5 dbi which equates to ~ 2x RF power output giving us an ERP of 200mw 
 
By comparison a Motorola handheld radio will have an ERP of 4w , and "store bought walkies"  will usual y be PMR446 with a ERP of 500mw atop of this they operate on 460Mhz as opposed to 2.4Ghz , so they are less susceptible to free-space loss and are more readily detracted and refracted compared to the 343.
 
Polarisation
Is an important factor for RF antennas and radio communications in general. Both RF antennas and electromagnetic waves are said to have a polarization.
 
For the electromagnetic wave the polarization is effectively the plane in which the electric wave vibrates. This is important when looking at antennas because they are sensitive to polarisation, and generally only receive or transmit a signal with a particular polarization.
 
For most antennas it is very easy to determine the polarization. It is simply in the same plane as the elements of the antenna. So a vertical antenna (i.e. one with vertical elements) will receive vertically polarised signals best and similarly a horizontal antenna will receive horizontally polarised signals.
 
Polarisation of an electromagnetic wave
empolarisation.gif
 
Higher Fq carriers are more reliant on matching polarization , if you were laying on the ground then your antenna would be "Horizontally Polarized" 
 
dipole-radiation-pattern-low.gif
 
 
The above diagram displays a vertical polarization from a vertical antenna, the majority of the radiated RF moves outward in all directions, however when you are laying on the ground the majority of the signal is send down in to the ground which then reflects back up , and the radiated energy exiting from your back is already going up, this creates all kinds of destructive interference as the carries pass over each other out of phase.
 
radiate.gif
 
 
 
The above diagram demonstrates the difference between a vertical (right) and horizontal (left) patterns, you can clearly see that if the recipient of the signal was located in front of you (assuming your body is on the red line) then virtually no RF is radiated forwards.
 
 
This coupled with the 2.4Ghz band and the low power output of 200mw ERP assuming a relatively high gain antenna would render your 343 pretty much as useful as a chocolate paperweight in a zero G furnace. For best effect use 343's in LOS (line of sight) only.
Edited by VPope

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Mission makers can turn this off in their missions individually if they chose to.

This is not a change that we will be changing globally as it would detract from the gameplay that we are trying to cater to.

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Is this in taught in some sort of UOTC Advanced RTO course?

 

Actually yes.  VPope has made a great course that can help with the use of radios.   "UOTC Radio Telephone Operator Theory"

 I attended  and I learned a lot.  Learned  that sometimes when I thought ACRE was broken it was my own fault.  Standing up is a great example.

 

EDIT:  I think the course was run 7 times in 2016

Edited by Jimbo

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Actually yes.  VPope has made a great course that can help with the use of radios.   "UOTC Radio Telephone Operator Theory"

 I attended  and I learned a lot.  Learned  that sometimes when I thought ACRE was broken it was my own fault.  Standing up is a great example.

 

EDIT:  I think the course was run 7 times in 2016

 

Vpope do you have something like a pdf  or overview of the theory of the course. I'd love to read it.

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Im currently refactoring the rto materials , there will in fact be an advanced course , should all be done in the next few weeks.

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I agree with the policy laid forth by Impulse.

As a radio operator in the signal section of a civil defense company I enjoy the realistic radio communication simulation ACRE provides us with

and thus I don't want to miss out on it, but of course when the terrain and distances in a mission do not allow proper communications (especially until any relay functions are implemented) occlusion should be disabled.

 

Mission makers should test the signal requirements of their mission and if necessary turn occlusion off, it is as simple as that.

Edited by zumorc

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90% of the time it is obvious when you're in terrain that it likely to cause signal problems. You should be planning for this like you would plan for any other battlefield obstacle.

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Thanks for the replies!  I am going to summarize this for my own benefit, but basically, because reasons (which I am sure are many and varied):

1. 343's and similar radios work much differently from the 'Walmart' radios that I am use to using.

2. The occlusion does more or less work according to signal polarization and other signal loss factors.

3. Radios fukkin suck mate.

 

Thanks this really helps me understand, and now I know what situations may be affecting comms and how to try to mitigate them.  This whole time I thought it must be just crappy oversimplified coding, but this proves me wrong.

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At this point I'm wondering why the military just don't start telling people to start using their favorite messaging app.

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Thanks for the replies!  I am going to summarize this for my own benefit, but basically, because reasons (which I am sure are many and varied):

1. 343's and similar radios work much differently from the 'Walmart' radios that I am use to using.

2. The occlusion does more or less work according to signal polarization and other signal loss factors.

3. Radios fukkin suck mate.

 

Thanks this really helps me understand, and now I know what situations may be affecting comms and how to try to mitigate them.  This whole time I thought it must be just crappy oversimplified coding, but this proves me wrong.

 

Nope, radios are shit. Trust me. My day job is space radios, which are about 1000x easier to talk to (no mountains in the sky). Terrestrial radios are much more fun for all the problems they have.

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At this point I'm wondering why the military just don't start telling people to start using their favorite messaging app.

 

For the first year or so when the Germans deployed their three PzH 2000s to Northern Afghanistan all Calls for Fire were made via Afghan cell phone, cause they couldn't get a decent radio communications setup/coverage going.

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Nope, radios are shit. Trust me. My day job is space radios, which are about 1000x easier to talk to (no mountains in the sky). Terrestrial radios are much more fun for all the problems they have.

 

IRL wouldn't simply elevating the ratio with your arm suffice in situations where microterrain is blocking the signal? If that's the case then I suppose an animation could be implemented on ACRE to represent this.

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IRL wouldn't simply elevating the ratio with your arm suffice in situations where microterrain is blocking the signal? If that's the case then I suppose an animation could be implemented on ACRE to represent this.

 

For small PRRs used in ditches, most certainly. However, I remember in training some bright spark used this in contact only for him, the section commander, to be told that his right arm and hand had been "shot". We got to see it from the enemy position, an entire section suppressing a ditchline only to see this gloved hand and small radio lifted above cover, it was like a little beacon that every rifle swept onto.

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For small PRRs used in ditches, most certainly. However, I remember in training some bright spark used this in contact only for him, the section commander, to be told that his right arm and hand had been "shot". We got to see it from the enemy position, an entire section suppressing a ditchline only to see this gloved hand and small radio lifted above cover, it was like a little beacon that every rifle swept onto.

It's an interesting compromise, most certainly. It would add some very interesting gameplay elements.

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At this point I'm wondering why the military just don't start telling people to start using their favorite messaging app.

 

You would be surprised how often cell phones are used

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FYI in a real war cellphones are not going to work.

 

Also no GPS, and good luck getting SATCOM links cause you can bet GEO birds are gone too.

 

Then you get to try and hit the emergency capability LEO birds which are probably being blown out of the sky in good order too.

 

FYI we're also all probably dead.

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