In article ,
"Michael A. Terrell" wrote:

Joseph Gwinn wrote:

In article ,
"Michael A. Terrell" wrote:

David Lesher wrote:

writes:

The FAA is planning as decommissioning as much ground equipment as

s/planning as/desperately hoping to/

possible. A primary driver for next-gen is the high cost of operating
and maintaining the ground based primary and secondary radars. A lot
of that stuff is quite old.

As noted by the fact they must buy tubes [yes, those things that glow..]
for some ARSR's [the longer-range radars] from St. Petersburg, and not
the Florida one. (The paperwork for an agency to procure things overseas
is mind-boggling; ISTM this actually has to get Hill approval.)


Which they wouldn't have to do, if our tax laws hadn't put the
domestic OEMs out of business. The cost to tool up for a small
production is high, and the ignorant tax laws killed them on inventory.
They did as much to kill US built electronics, as cheap imports.

Richardson Electronics has picked up most of the residue form domestic
transmitting tube capabilities.


There is indeed a lot of concern over the loss of too much
infrastructure that can track uncooperative targets that can now be
tracked with primary radar, and how many radars are to remain is being
debated.


Output power for modular solid state microwave gear keeps climbing.
If they can build 5 MW UHF TV transmitters, they can build acceptable
solid state modular RADAR gear. The new solid state receivers have a
lot lower noise floor, which reduces the raw RF that has to be
transmitted, as well.

Solid state UHF radar transmitters have been around since the 1980s.

http://www.fas.org/spp/military/program/track/pavepaws.htm

The purchase price is higher than vacuum tube, but the maintenance cost
is lower, especially for systems that must operate 24x7x365 with ~100%
availability.


I was talking about the megawatt variety, like the pair of vacuum
tube Westinghoue 2 MW units tat were at Carin Airfield in the '70s. The
nice thing about a modular transmitter is that some of the outputs can
fail, and the system will still operate.

Early warning radars do operate at near megawatt RF power levels. The
power level is chosen based on what the radar needs to do, and how
quickly it must do it. There is no technological limit to prevent
megawatt power levels.


Cincinnati Electronics was building some solid state replacement
RADAR gear for the military, as drop in replacements in the mid '70s.
They still had a huge WW-II shipboard antenna on the roof of the complex
to test the full RADAR equipment.

There are still some WW2 radars on older surface ships. Those old
radars were built very well. What eventually kills them is
unavailability of repair parts and/or the oldtimers that know what to do
with those parts.

And those ubiquitous spinning-bar marine radars one sees on all manner
of small boats are a WW2 architecture rendered with solid-state
electronics, except for the magnetron. The main improvements compared
to WW2 designs are the spinning-bar antenna, which has much lower
sidelobes than typical in WW2 designs, and better clutter reduction
algorithms in the receiver. And the use of computer displays, not CRTs
with rotating magnetic fields to yield the PPI display.

Joe Gwinn