F-14 data link performance

Having flown basically all the modern fighters online I couldn't help but notice that the F-14's data link doesn't seem to recieve signals from the AWACS when down in the mountains like the other aircraft do.

Shouldn't the F-14 be just as capable of recieving the AWACS DL signals as the other aircraft?

Are you in the AWACS' LOS?

Maybe the other aircraft shouldn't be as capable instead.

Something to keep in mind regarding GG's remark- there's a caper known in EW circles from ODS where Navy had to run a hundred miles worth of cable across the desert to maintain repeaters for Link signals off of Air Force E-3s to the fleet, because the USAF refused to adjust the southeastern AEW track slightly to keep them in signal strength range.

The magic behind these things is far closer to your kid's $10 magician's kit than David Copperfield.

I have absolutely minimal knowledge about this, but I was under the impression that the DL signals were sent via radio and that these signals were readily reflected inside the mountain valleys depending on the angles.

In other words whilst the AWACS radar can't see you or anyone else hiding in the mountain valleys, it can still send you data signals regarding the position of those it can see flying around in the open.

Am I right about this?

Either way it would be very nice if all the aircraft ingame were treated equally when it comes to DL signals.

They should be treated with regards to the information available concerning their function, signal power, calculated propogation and falloff, honoring LOS in accordance with transmitter capability.

Problem is, some modules are far better modeled in these (and other EW) respects than others.

I have absolutely minimal knowledge about this, but I was under the impression that the DL signals were sent via radio and that these signals were readily reflected inside the mountain valleys depending on the angles.

 

In other words whilst the AWACS radar can't see you or anyone else hiding in the mountain valleys, it can still send you data signals regarding the position of those it can see flying around in the open.

 

Am I right about this?

 

Either way it would be very nice if all the aircraft ingame were treated equally when it comes to DL signals.

yea thats largely true, especially when pertaining to Older datalinks.

But Link 16's like the one on the Hornet for EG don't have to be sent by radio emissions. Various open sources that says that link 16 can be alternatively transmit data over a sort of Wide area Networks utilizing TCP/IP network protocols as we do for our personal computers when connected to a network, and thus not requiring direct LOS .

I have absolutely minimal knowledge about this, but I was under the impression that the DL signals were sent via radio and that these signals were readily reflected inside the mountain valleys depending on the angles.

 

In other words whilst the AWACS radar can't see you or anyone else hiding in the mountain valleys, it can still send you data signals regarding the position of those it can see flying around in the open.

 

Am I right about this?

 

Either way it would be very nice if all the aircraft ingame were treated equally when it comes to DL signals.

Actually, both Link 4 and Link 16 are very much line of sight only, the Link 16 even more so as it has a higher frequency. If you don't have a direct line of sight to the AWACS you'd have a real hard time getting a link. With the AWACS usually being at high altitudes it can sometimes work as you'd be looking up from a valley towards it but still hard.

Maybe the other aircraft shouldn't be as capable instead.

This!

yea thats largely true, especially when pertaining to Older datalinks.

 

But Link 16's like the one on the Hornet for EG don't have to be sent by radio emissions. Various open sources that says that link 16 can be alternatively transmit data over a sort of Wide area Networks utilizing TCP/IP network protocols as we do for our personal computers, and thus not requiring direct LOS .

Uhm and how do you think the AWACS does access the network? They still have to transmit radio signals to access these networks. At least I've never seen an E-3 dragging an ethernet cable behind it :D

What are the data link frequencies overall? Are they high or low? As if they are high, it might be line of sight by requirement. And lower you go, more diffraction you get and you can even get signals behind the mountains. But higher you go, you can bounce it from the ionosphere, but you have skip distances.

You really want to have a datalink to be such that you can cover as much the terrain / volume you have, not restricted to line of sight. Because you have troops on the ground, going through the mountains etc, and they need to be able transmit their data regardless which side of the hill they are.

It is better to example wait a 10 seconds to get the data transmitted and even few tries, than require to move the mountain hill side that can take a day or two.

So if the Link-16 is 960–1,215 MHz, then it is line of sight.

Lower you go, you are limiting the amount of data you can transmit, period of the transmission and for how many you can transmit at once, but you get extremely great coverage across the whole globe, but you need larger antennas as well, so it becomes impossible for some point for fighters to go lower frequency as they can't do like what submarines can do by dragging a couple kilometer long antenna behind them.

You really want to have a datalink to be such that you can cover as much the terrain / volume you have, not restricted to line of sight. Because you have troops on the ground, going through the mountains etc, and they need to be able transmit their data regardless which side of the hill they are.

This is what repeaters are for. They can be ground-based or airborne, or in some cases space-borne. You aren't always guaranteed coverage either way.

This!

 

 

Uhm and how do you think the AWACS does access the network? They still have to transmit radio signals to access these networks. At least I've never seen an E-3 dragging an ethernet cable behind it :D

Satellites?

This is what repeaters are for. They can be ground-based or airborne, or in some cases space-borne. You aren't always guaranteed coverage either way.

or what he said?

I'm not sure how this is handled in DCS, but the F-14A/B did not have LINK 16, but rather LINK 4A and 4C. LINK 4 operates in the clear, and in the UHF band, rather than the EHF frequencies used by LINK 16. LINK 4 and 16 are not interoperable.

Heatblur modeled the LINK 4A and 4C system in the DCS Tomcat. http://www.heatblur.se/F-14Manual/general.html#link-4a-c-data-link

There is also a good discussion here: https://forums.eagle.ru/showthread.php?t=169817

TeamMaximus

I'm not sure how this is handled in DCS, but the F-14A/B did not have LINK 16, but rather LINK 4A and 4C. LINK 4 operates in the clear, and in the UHF band, rather than the EHF frequencies used by LINK 16. LINK 4 and 16 are not interoperable.

 

Heatblur modeled the LINK 4A and 4C system in the DCS Tomcat. http://www.heatblur.se/F-14Manual/general.html#link-4a-c-data-link

 

There is also a good discussion here: https://forums.eagle.ru/showthread.php?t=169817

 

TeamMaximus

we know that but the mention of Link 16 came about because some people were implying other datalinks on other aircraft work better than they should in comparisong to Link4 on the tomcat

yea thats largely true, especially when pertaining to Older datalinks.

 

But Link 16's like the one on the Hornet for EG don't have to be sent by radio emissions. Various open sources that says that link 16 can be alternatively transmit data over a sort of Wide area Networks utilizing TCP/IP network protocols as we do for our personal computers, and thus not requiring direct LOS .

Uhm and how do you think the AWACS does access the network? They still have to transmit radio signals to access these networks. At least I've never seen an E-3 dragging an ethernet cable behind it

Satellites?

And how do they communicate with Satellites? Right, radio emissions!

And how do they communicate with Satellites? Right, radio emissions!

And so does a search radar emit radio waves.... doesn't mean you can broadcast music or use it as a computer network. or vice versa just because UHF/VHF emits radio waves to transmit voice signals doesn't mean it can be turned into a search radar.

It's really not the exact same thing.

In any case That was irrelevant, you are missing the point which is being satellites are from above you, there is no terrain disrupting signals unless you are going tell me you are to be flying in an underground tunnel. Link 4 radio signals on the other hand entirely LOS from other aircraft.

Lots of great info here, thanks guys.

What I can say is that in DCS the F/A-18 and Su27/J-11 both recieve data link signals a lot deeper into the mountains than the F-14, and seemingly also at much greater distances. Wether this difference is correct or not is the primary question.

As people noted earlier, it is likely due to less flexible modelling of the Heatblur F14 Data Link propagation (so, it cuts out sooner as LOS degrades or is cut completely). I couldn't comment on 'correctness' as I'm not privvy to the maths ED or Heatblur use for propogation of these signals.

It is possible that the Link 16 ability to 'daisy chain' through other, closer aircraft (and higher) aircraft is getting you a signal. I believe LINK 4 is Point-to-point only.

As people noted earlier, it is likely due to less flexible modelling of the Heatblur F14 Data Link propagation

Less flexible than EDs Link-16 propagation? Well, correct me if I'm wrong, but I think EDs Link-16 simulation doesn't take geography into account at all besides range maybe.

But higher you go, you can bounce it from the ionosphere, but you have skip distances.

Younger brother was a Radio Officer on an oil rig, one of the modes of communication he used was what is called Tropo-scatter, he described it as warming up a bit of sky hoping to bounce the signal over the horizon :)

This is what repeaters are for. They can be ground-based or airborne, or in some cases space-borne. You aren't always guaranteed coverage either way.

Even in Ham Radio we use satellites to re-broadcast or repeat signals, tho most of them use a widely separated frequency input to output to prevent desensitising the receiver on the satellite.