I've only been in the forum for a few minutes but already I'm hooked.

My question concerns a possible advantage of using SARH(Semi-Active Radar Homing) missiles over active radar guided missiles. I know that SARH missiles use the radar signals from the launching aircraft the guide themselves to the target, so the launching aircraft may be able to see through countermeasures, if you know what I mean. However, an actively guided missile does not require the launching aircraft to maintain a lock until impact. So if the active radar missile can get spoofed by chaff. Then it has no way to re-attain a lock on the correct target. But in using a SARH missile it seems that the launching aircraft's radar could give the missile a "second chance" by directing the missile back to the correct target.

I guess this is more of wondering if I'm right rather that a question, although I probably don't fully understand the behavior of a missile. If you don't understand what I am saying then please tell me and I'll try to explain it again in English ;)

To simplify the issue, compare the late model Sparrows, AIM-9M against their ARH counterparts(AIM-120).
The AIM-120 offers BOTH a "semi" SARH and ARH mode of launch.
The AIM-7 is limited completely to SARH.

It's easy to think the SARH gives you a "second chance." That's not true. Once the first missile has gone wild, you may as well take another missile shot.

That said, there IS an advantage to SARH, mostly against ground clutter where if you're operating a high power radar like that on a 14 or 15, you can really light up your target. Even in semi SARH, you'll let the missile get close enough that power limitations don't matter. Other than that, in typical BVR engagements, SARH is only a liability.