Question about the APG-77

Scott Ferrin wrote in message
...


In the latest AW&ST it mentions the F-22's radar as having a range of
"over 100 miles" and implies that it's greater than the F-15's. I
recall reading MANY times in the 80's of the Eagle's radar being more
like 150 miles and the Tomcat's nearly 200. I've also read that the
ASG-18 in the YF-12 (which was the one the AWG-9 was based on) was
good for over 300. So what gives? Are they purposly underselling
the APG-77? Is the "over 100 miles" figure against fighter-sized
targets while the high figures of the other radars were against
bomber-sized targets? Inquiring minds want to know.

I'd like to know as well. The F-15s in question were supposed to be equipped
with AESA antennas using the same T/R modules used in the F-22's antenna.
The aperatures are about the same size and the back end processing
algorithms are likely the same generation so I'd expect about equal
detection range.

On Sun, 30 May 2004 17:21:01 -0400, "Paul F Austin"
wrote:


Scott Ferrin wrote in message
.. .


In the latest AW&ST it mentions the F-22's radar as having a range of
"over 100 miles" and implies that it's greater than the F-15's. I
recall reading MANY times in the 80's of the Eagle's radar being more
like 150 miles and the Tomcat's nearly 200. I've also read that the
ASG-18 in the YF-12 (which was the one the AWG-9 was based on) was
good for over 300. So what gives? Are they purposly underselling
the APG-77? Is the "over 100 miles" figure against fighter-sized
targets while the high figures of the other radars were against
bomber-sized targets? Inquiring minds want to know.

I'd like to know as well. The F-15s in question were supposed to be equipped
with AESA antennas using the same T/R modules used in the F-22's antenna.
The aperatures are about the same size and the back end processing
algorithms are likely the same generation so I'd expect about equal
detection range.

Are you sure about that? ISTR the nose of the F-22 being quite a bit
shorter top-to-bottom than the Eagle's. I know the bulkhead the
APG-77 is mounted on is tilted back a bit but not that much. Is the
number of modules on the two the same? Also the F-22 went to liquid
cooling of the avionics presumably because they draw a lot more power.
I remember reading that the APG-77 is unusually powerful.

Scott Ferrin wrote in message
...
On Sun, 30 May 2004 17:21:01 -0400, "Paul F Austin"
wrote:


Scott Ferrin wrote in message
.. .


In the latest AW&ST it mentions the F-22's radar as having a range of
"over 100 miles" and implies that it's greater than the F-15's. I
recall reading MANY times in the 80's of the Eagle's radar being more
like 150 miles and the Tomcat's nearly 200. I've also read that the
ASG-18 in the YF-12 (which was the one the AWG-9 was based on) was
good for over 300. So what gives? Are they purposly underselling
the APG-77? Is the "over 100 miles" figure against fighter-sized
targets while the high figures of the other radars were against
bomber-sized targets? Inquiring minds want to know.

I'd like to know as well. The F-15s in question were supposed to be
equipped
with AESA antennas using the same T/R modules used in the F-22's antenna.
The aperatures are about the same size and the back end processing
algorithms are likely the same generation so I'd expect about equal
detection range.

Are you sure about that? ISTR the nose of the F-22 being quite a bit
shorter top-to-bottom than the Eagle's. I know the bulkhead the
APG-77 is mounted on is tilted back a bit but not that much. Is the
number of modules on the two the same? Also the F-22 went to liquid
cooling of the avionics presumably because they draw a lot more power.
I remember reading that the APG-77 is unusually powerful.

That's what I mean. The F-22 nose is certainly not larger than the F-15
radome (42 inches IRRC). The F-15C AESA aperature may be sparsely populated
with T/R modules which would account for the difference in performance. T/R
modules are still on the cost-volume ski slope, still pretty expensive.