Once again I do not claim to know the abilities of the SAMPSON radar. I haven’t been able to find any reliable specks on it. I know that it is highly though of by people that should know and I assume it meets all the requirements it was designed to preform whatever those unknown specks were it was designed to meet.
Perhaps it would be beneficial to some of the members on the thread to review some of the challenges when comparing the two radar types, so as to clear up confusion. First there is no doubt whatsoever that an active phase array type radar from the system architectural point of view is superior to a phase shifting radar configuration. I will not go into all of the reasons, some of which are very obvious and some of which are not so obvious but they are real and dramatic. This recognition is why they have been in active development for over forty years. Yes that is right they have been working on them for over forty years that I know of. But the reason we have not seen them deployed until recently are the challenges in making the components and not as some have stated, their great cost or lack of need.
They are very expensive to make but on the other hand they are relatively cheaper to maintain and they are much more reliable and rugged in field use. Complete life cycle costs are not that much different. Phase array radars are very computer intensive devices and they can always use more computing power with which to do ever more wonderful things but the real challenges are not found in computer limitations because they can still do many, though fewer, wonderful things with modest computer power, using today’s standards.
I will concentrate on only the two most challenging technical issues and will not even get into the critical mechanical ones though they too are difficult they are within common technology standards. The first is the RF semiconductor components and the second and closely related cooling issues which are again closely related with and also directly related to the operating frequency. The higher the operating frequency the more challenging are the cooling issues. The active gating device in any electronic or optical system mush have physical dimension less than one quarter the wavelength of the highest frequency used. That means that as the frequency goes up the physical size of the active devices must go down. The smaller the active controlling sight of the waveform (be they gates, switches, amplifiers, delay-lines ect.) which physically are the places where most of the heat is generated, the harder they are to cool. That is why it is so hard to get high powered output at high frequencies in RF devices. With too much power in a small spaces they just melt, even if they can handle the high voltages that also come with high power.
The original drive to produce active arrays was not for all of their wonderful beam-forming and scanning capacities (at the time there were no computers that could do it) for which they were theoretically capable but just to produce more power by using multiple transmitting sources.
Now we start getting into the real problems. Even for a flat array that is only meant to produces a fixed non-changing beam, all of the carefully positions point sources must have exactly (and I mean exactly) the very same frequency, the same phase, the same on/off timing, and the same power output. Plus they must maintain these critical features as they heat up and cool down along with changing use demands and the weather.
Have any of you ever tried to match just two output tubes on a high end audio amplifier for all of you stereo buffs out there?
And that is just on the transmitting side. On the receiving side there are even harder to maintain consistencies because they have noise, timeing are detecting issues all of their own. Don’t you just hate drift?
These are not problems found when you have a single RF source and a single RF receiver. The phase shifters are very big, heavy which also makes them very stable and much easier to control, stabilize, and predicable to compensate for with the changes in temperature.
Active phase technology could never be done with tube technology because of the variances found in their manufacturing process of tubes. Semiconductors and their manufacturing process are much more uniform and consistent but the tolerances are still very critical and they produce a lot of heat in a small space. It has required the creation of completely new semiconductor materials, (both for the frequency range and heat tolerance) which are by-in-large not found within commercial products. There is still very much to learn about manufacturing these new specialized semiconductors, while on the other hand the older phase shifting technology has decades of refinement behind it. So it is not unreasonable to conclude that at least at this point in time, a highly refined SPY-1 radar, in its lasted version, would have similar but not exactly the capacities of a SAMPSON radar. And we are not even talking about all the radar controlling software that is always under continuing refinement and has consumed and will continue to consume millions of man-years of development until the end of time.
