From: waltbj@oneimage.com
Subject: Re: F-104 Stealthy Lockon
Newsgroups: rec.aviation.military
Date: 13 Aug 98 19:19:35 GMT

Dweezil Dwarftosser <wcsys@usa.net> wrote:
>Quick question:>
>Were the rumors about the unusual F-104 radar dish true ?
>I never saw one with the radome open.
>>- John T., former MSgt, USAF - and member of the  1st, 4th, 15th
>        36th, 50th, 56th, 86th, and 388th ( Korat Dive Toss )
>                  Tactical Fighter Wings.
>

Indeed it was. The first time I saw one running (on the test bench)
I almost broke out laughing. The ASG14 was a very simple set even
compared to the to the E4(F86D). It used a spiral scan about a fixed
axis about 3 degrees (I think) below the aircraft waterline. In search
the entire antenna dish and feedhorn assembly was spinning about 100
rpm and slowly 'opened up' from dead center to 45 degrees off boresight.
That took about 3 seconds. Then it snapped back to center (the test
bench seemed to jump) and the cycle repeated. The max range on the scope
was 20 n.m. If you picked up a target the blip was a small segment of an
arc if it was 45 off axis, the length of the arc increasing as as the angle
off axis decerased until when it ws on axis the blip became a complete circle.
There was no angle track capability at all; the pilot did that by flying the
104 to point at the blip. Once inside 10nm the pilot could lock on in range
only by depressing the radar ranging button on the stick. The antenna stopped
its diverging scan and simply spun about the boresight axis. The pilot could
position a range gate over teh target and once locked on the set fed radar
range to the gunsight's ballistic computer. A needle in a gauge at the bottom
of the scope indicated overtake. The sight reticle would indicate range in nm
if missiles were selected, 1000s of feet if guns were selected. The radar was
tunable to combat ECM and also had a tunable ECM HOME function where it was in
receive-only. (This did work quite well on B52s and EB57s) There was also an IR
sight - that hafmoon window at the base of the armored windshield - that used a
scanning system like a Nipkow disc TV set of the early days. There were 2
spinning discs, one with an arc shaped slit running one way, the other
with a reverse arc.  If there was no target out there, the senstive CdS
(I think) element's output was cut off by an AGC-like circuit. But a spot
IR target would result in a momentary signal and that, amplified, would
flash a neon bulb. The resulting flash would be foucssed through a pair
of similar synchronised spinning discs and that output was reflected off
the gunsight combining glass. The resulting 'arced cross' was visible to
the pilot and he flew the aircraft to put the pipper on the cross. The
range was adequate for guns, around 3-4000 feet. As simple and as crude
as it sounds, it worked!  The AIM9Bs were boresighted along with the
radar and the gunsight. I got to shoot at a Firebee once and I was
tracking the drone strictly on radar. When I got a mile behind it I
called "Flares" and seconds later heard the buzzing growl in the missile.
I looked up through the sight and the pipper was on the flare. The
missile then knocked the flare off its mount. (The warhead was clipped to
save the drone - #2 got the other flare and #3 got the drone itself.

  All in all the ASG14 was a simple reliable and effective weapons system - it's
simplicity was enabled by the 104's ability to catch anything it was after.

  After exepriencing the slavery required to maintain an F86D/E4 and then
the F102's MG10 with its incessant need for WSEM (missile system) testing
the 104/ASG14 was a real treat. Imagine changing the radar package in 20
minutes! And aircraft availability averaged <AVERAGED> over 90%! What a
change from even the F102!

    Walt BJ ftr plt ret