[WAD] ESM detection range

[CoryC]

Hi all,

Went through the Battle of Latakia scenario the other day.

Out of curiousity I set up a test with a Saar class (with radars off) running at an Osa class (radars all on). I noticed they detected eachother around the same time.

Shouldn't active radar emissions be getting picked up long before the active radar gets into it's horizon?

[Jakob Wedman]

Thanks - the request is already reported [:)]
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[CoryC]

I tried another test last night with a Udaloy and a Type 42 steaming at each other, the Udaloy radars on and the 42 radars off. They detected eachother around the same time.

Is this in the pipeline to be looked at, or am I incorrect about the ESM thing perhaps?

[Dimitris]

They are both horizon-limited. So for example if the Udaloy can detect the Type 42 actively at e.g. 20nm, and the Type 42 can passively detect the Udaloy at 15nm, but the effective radar horizon between them is e.g. 10nm (this can vary with weather conditions), then both will detect each other at 10nm.

To remove the horizon as a factor in your radar/ESM tests, you must try a ship against a high-altitude aircraft or satellite.

[CoryC]

Active radars can be detected (via ESM) far beyond the horizon no?

[ChezDaJez]

ORIGINAL: CoryC

Active radars can be detected (via ESM) far beyond the horizon no?

Typically cold war ESM receivers such as the ALQ-78 and ALR-66 could detect emitters at about 1.5 times the theorectical range of the emitter assuming line of sight. However the height of the emitter and the receiver determines what impact the horizon might have on detection range.

Chez

[ExNusquam]

ORIGINAL: CoryC

Active radars can be detected (via ESM) far beyond the horizon no?

Some ESM systems support OTH, but not all. It's modeled on a per-emitter basis in Command.

[scottb613]

Hi Folks,

From my experience - qualified AN/WLR-1H operator - I was always under the impression that we could detect signals beyond the radar horizon - while I know that radar needs direct line of site - I think the emissions scatter a bit at range making it perfect fodder for ESM systems to sniff out... Then again - 90% of my time "on the stack" was at Periscope Depth - where you probably had to be a bit closer than the radar horizon to actually pick us up... Just my nickels worth...

Hah - the only way those P-3 guys could catch us is if we gave them our GPS position - course - speed - surfaced - and - launched flares... Right Chez ?
[:D]

Regards,
Scott

[Flef]

Typically cold war ESM receivers such as the ALQ-78 and ALR-66 could detect emitters at about 1.5 times the theorectical range of the emitter assuming line of sight. However the height of the emitter and the receiver determines what impact the horizon might have on detection range.

I was always under the impression that we could detect signals beyond the radar horizon - while I know that radar needs direct line of site - I think the emissions scatter a bit at range making it perfect fodder for ESM systems to sniff out...

VHF and UHF love the troposphere thermal inversions. You can also catch a lot of scatter and reflexion due to the ionosphere.
After... well... there is a lot of phenomenons that can propagate a signal further than the horizon.

[ChezDaJez]

ORIGINAL: scottb613

Hi Folks,

From my experience - qualified AN/WLR-1H operator - I was always under the impression that we could detect signals beyond the radar horizon - while I know that radar needs direct line of site - I think the emissions scatter a bit at range making it perfect fodder for ESM systems to sniff out... Then again - 90% of my time "on the stack" was at Periscope Depth - where you probably had to be a bit closer than the radar horizon to actually pick us up... Just my nickels worth...

Hah - the only way those P-3 guys could catch us is if we gave them our GPS position - course - speed - surfaced - and - launched flares... Right Chez ?
[:D]

Regards,
Scott

Hi Scott

Search radar waves do scatter a bit and can be detected a little beyond the horizon but not at any significant distance beyond.

Of course, when I was flying, we didn't have the niceties of today... no satnav, no fancy computers. Just good old pencil and chart. The best it got for us was inertial nav. The more yanking and banking you did, the worse the position estimate.

The only time we ever saw flares from you bubbleheads was when the exercise started and when you surrendered!

Chez

[scottb613]

The only time we ever saw flares from you bubbleheads was when the exercise started and when you surrendered!

Not too shabby for a brown shoe... LOL - have a good day Chez...
[:)]

Regards,
Scott

[Dimitris]

We have distinct formulas for radar & visual horizons, and in addition the radar horizon is affected by a few environmental conditions (incl. sea state; the sea surface acts most effective as a conduit for radio waves when it's calmest).