Ed Rasimus wrote:

Guy Alcala wrote:

Ed Rasimus wrote:

Guy Alcala wrote:

"The Air Force also conducted a quick look evaluation of a potential APR-26
replacement in April [1966].

Not to disparage Jenkins, who's done great research on the F-105, but
"potential replacement in April (1966)" doesn't track well with my
experience. I arrived at Korat in May of '66 and at that time the
APR-25/26 was just being initially installed in the operational jets.

As noted below, this was the WWIII fit, and they were just starting procurement.

OK, WW III was the F-105F. And the elaboration that it was
pre-deployment of the system helps, but it still doesn't make sense to
be seeking a replacement before you've operationally employed the
already purchased equipment. Things were happening fast in EW at that
time, so maybe that's the excuse.

Yes, they had multiple systems in concurrent development, and were essentially trying everything.

snip

So, Low PRF would indicate general search mode, High PRF would indicate tracking
_somebody_ (at shorter range). That at least would be the case with the APR-25.

About ten minutes after that post above, an aging synapse fired and I
recalled that 25/26 didn't really deal with Azimuth/Sector, but the Lo
PRF was search and the Hi PRF was switching to track mode.

Yeah, I thought you might be conjoining APR-25/-26 with -36/-37.


So, prior to the ALR-31/APR-36, you might be in one or both beams and getting High
PRF, but not be in the center of the Fan Song sweep because it was actually
targeting some other a/c close to the same angle between the radar and you, leading
to unnecessary maneuvers and high pulse rates. You'd also pick up the L-band
guidance signal, again without necessarily being the target.

When missile data upload was taking place, another
frequency was employed (that's where an EW could tell you more) you
got an "Activity" light and when command guidance signals were
received, indicating control signals to the missile airborne, you got
the "Launch" light.

Right, the guidance used the C-band dish on the left of this picture (the E/F or
G-band tracking antennas are the horizontal and vertical troughs):

http://fas.org/nuke/guide/russia/airdef/fan_song2.jpg

Here's what I'm talking about (again from the Air & Space article
Bob pointed out):

"As tactics were developed in the air, field modifications to the Wild Weasel
systems continued on the ground. A key weakness of the equipment was that if
several SAM sites were displayed on the scope and the light that signaled a launch
was illuminated, there was no way to know which site had fired and from which
direction the SAM was coming. "I heard the crews complaining about that," says
Weldon Bauman, who in 1967 was a junior enlisted technician at Takhli. "---details snipped---

No ****! You bet we were complaining. It was a "good news/bad news"
kind of thing. We were glad the RHAW gave us info, but really wanted
more detail. Discrimination between radars in the saturated
environment of Pack VI was important and knowing where to look in a
split-second to acquire the missile visually was critical to survival.

One hopes they gave Bauman a DSM. Rare for enlisted, but not unknown. They gave one to Senior
Chief Radarman Nowell, the senior controller on U.S.S. Chicago in 1972 (aka "The Voice of Red
Crown"), for his controlling of 13 successful interceptions. Admittedly, he was only the second
navy enlisted man to be awarded one, but Bauman's work would seem to be as important. Googling I
see that he's an inductee of the Association of Old Crows Hall of Fame for "Missile
Warning/Launch Circuits."


Thanks. BTW, in the case of say a two-ringer growing to a three, did the strobe
extend in from the periphery, or out from the center? I've always assumed it was
the latter (looking similar to a PPI display), but I've never seen a source I trust
which says which it was.

You are correct. The "origin" of all strobes was the center of the
scope. The strobe extended outward in the direction indicated by the
integration of signal strength from the several antennae on the
aircraft skin. Lot of folks never really broke the code that the
length of strobe (1-ring, 3-ring, etc.) was signal strength not
proximity to the emitter. There was some correlation, but technically
it was strength not range.

Thanks. I knew that that generation of RWRs indicated signal stength rather than range. What was
the problem with crews not being able to grok it? I assume they were told what the strobe length
represented, so was it a cognitive problem in combat, i.e the brain is used to seeing a vector
length represent distance, so they automatically reverted to that under pressure?


In less saturated areas, we could often work a single Fan Song and get
station-passage, just like flying over a VOR. On the nose, on the
nose, then swing to the tail. Good way to find a likely spot to leave
some CBU.

Better you than me, although flying directly overhead is probably fairly safe as you'd be inside
SA-2 minimum range. It's a damned good thing that they didn't have any shorter-ranged SAMs
(co-located with the SA-2s), or I fear you would have only been able to do this once, if that ;-)

Guy