The F-5E experienced numerous upgrades in its service life, with the most significant one being adopting a new planar array radar, Emerson AN/APQ-159 with a range of 20 nmi to replace the original AN/APQ-153.
Similar radar upgrades were also proposed for F-5F, with the derivative of AN/APQ-159, the AN/APQ-167, to replace the AN/APQ-157, but that was cancelled.
The latest radar upgrade included the Emerson AN/APG-69, which was the successor of AN/APQ-159, incorporating mapping capability.
However, most nations chose not to upgrade for financial reasons, and the radar saw very little service in USAF aggressor squadrons and Swiss Air Force.

Various F-5 versions remain in service with many nations.
Singapore has approximately 49 modernized and re-designated F-5S (single-seat) and F-5T (two-seat) aircraft.
Upgrades include new FIAR Grifo-F X-band radar from Galileo Avionica (similar in performance to the AN/APG-69), updated cockpits with multi-function displays, and compatibility with the AIM-120 AMRAAM and Rafael Python air-to-air missiles.

One NASA F-5E was given a modified fuselage shape for its employment in the Shaped Sonic Boom Demonstration program carried out by DARPA.
It is preserved in the Valiant Air Command Warbird Museum at Titusville, Florida.

The Royal Thai Air Force (RTAF) had their F-5s undergo an extensive upgrade program, resulting in the aircraft re-designated as F-5T Tigris.
They are armed with Python III and IV missiles; and equipped with the Dash helmet-mounted cueing system.

Similar programs have been carried out in Chile and Brazil with the help of Elbit.
The Chilean upgrade, called the F-5 Tiger III Plus, incorporated a new Elta EL/M-2032 radar and other improvements.
The Brazilian program, re-designated as F-5M, adds a new Grifo-F radar along with several avionics and cockpit refurbishments, including the Dash helmet.
The F-5M has been equipped with new weapon systems such as the Beyond Visual Range Derby missile, Python IV short-range air-to-air missile, SMKBs smart bomb, and several other weapons.
The F-5E experienced numerous upgrades in its service life, with the most significant one being adopting a new planar array radar, Emerson AN/APQ-159 with a range of 20 nmi to replace the original AN/APQ-153. Similar radar upgrades were also proposed for F-5F, with the derivative of AN/APQ-159, the AN/APQ-167, to replace the AN/APQ-157, but that was cancelled. The latest radar upgrade included the Emerson AN/APG-69, which was the successor of AN/APQ-159, incorporating mapping capability. However, most nations chose not to upgrade for financial reasons, and the radar saw very little service in USAF aggressor squadrons and Swiss Air Force.
Various F-5 versions remain in service with many nations. Singapore has approximately 49 modernized and re-designated F-5S (single-seat) and F-5T (two-seat) aircraft. Upgrades include new FIAR Grifo-F X-band radar from Galileo Avionica (similar in performance to the AN/APG-69), updated cockpits with multi-function displays, and compatibility with the AIM-120 AMRAAM and Rafael Python air-to-air missiles.
One NASA F-5E was given a modified fuselage shape for its employment in the Shaped Sonic Boom Demonstration program carried out by DARPA. It is preserved in the Valiant Air Command Warbird Museum at Titusville, Florida.
The Royal Thai Air Force (RTAF) had their F-5s undergo an extensive upgrade program, resulting in the aircraft re-designated as F-5T Tigris. They are armed with Python III and IV missiles; and equipped with the Dash helmet-mounted cueing system.
Similar programs have been carried out in Chile and Brazil with the help of Elbit. The Chilean upgrade, called the F-5 Tiger III Plus, incorporated a new Elta EL/M-2032 radar and other improvements. The Brazilian program, re-designated as F-5M, adds a new Grifo-F radar along with several avionics and cockpit refurbishments, including the Dash helmet. The F-5M has been equipped with new weapon systems such as the Beyond Visual Range Derby missile, Python IV short-range air-to-air missile, SMKBs smart bomb, and several other weapons.
Northrop F-5