Talk:AN/FPS-24 radar

I don't think the frequency band stated in this article is correct. My memory says that the FPS-24 was a UHF radar, with a frequency in the 'gap' that is designated between the upper and lower UHF television bands. LarryB55 (talk) 01:06, 10 November 2011 (UTC)

Avco or General Electric???
Which one manufactured the FPS-24? The title says Avco; the body of the page says General Electric. I was a crew chief on this radar and I cannot remember. I think it was GE; and I think it was Avco that built the FPS-26. LarryB55 (talk) 00:06, 16 November 2011 (UTC)


 * The radomes.org reference, which is an authoritative source, states that the FPS-24 was manufactured by General Electric. I changed this within the body of the page; however I don't know how to correct the title. Can someone else with a bit more talent do that?


 * ✅ Fountains of Bryn Mawr (talk) 14:01, 16 November 2011 (UTC)

FPS-24 Transmitter Output Power
As a former crew chief (and site technical instructor) on the FPS-24 at Cottonwood, I recall the transmitter output power as 10 Megawatts. I am positive I am correct on this. Perhaps the person who changed this to 5 MW has an authoritaive reference for the change?

Incidentally, I also believe that the frequency may have been mis-stated. I believe the operating frequency was in the 'gap' between the upper UHF television band and the lower UHF television band. This I don't have a reference for, and my memory is less sure than it is on the power output number. — Preceding unsigned comment added by LarryB55 (talk • contribs) 00:25, 26 November 2011 (UTC)

Other issues, some to be undone
I like some of the edits made; however let me clarify some points prior to editing the edits. I don't want to undo the most recent edits without further discussion.

1. 'Frequency Diversity' versus 'Frequency Diverse'. "Frequency Diversity" was the term in use at the time this radar was in service. 'Frequency Diversity' was a technology. An advantage when under attack by electronic countermeasures was the ability of the FPS-24 radar operator to readily shift the operating frequency of the radar away from the frequency of incoming jamming. The FPS-24's operating range may have been considered by some as diverse, ie tunable over a diverse (note lower case) range (to stretch a usage), but I assure you, in the technical parlance of the day the ability to shift frequency away from ECM was referred to as Frequency Diversity (note upper case), and thus the FPS-24 was referred to as "a Frequency Diversity" radar.

2. I kind of like the change to 'rigid coaxial cable', because I don't know how else to characterize it, but it was not truly a cable...it was a 9" diameter alumninum 'pipe' with a fairly hefty center conductor. In my mind the use of the word 'cable' implies a flexible conductor of some sort, but there was absolutely *nothing* flexible about the FPS-24's RF conductor. Ah, maybe 'rigid coaxial conductor' might be a more accurate term???

3. Interference reported by nearby neighbors: When Cottonwood's FPS-24 was initially deployed the output pulse of *10 MW* set up standing waves in the transmitter of Grangeville, Idaho's, low power AM radio station KORT, about 20 miles away as the crow flys. Several times the resultant arcing in KORT's transmitter knocked the radio transmitter off the air. The problem was resolved when engineers from the USAF went to KORT and modified the transmitter with filters to shunt the FPS-24 noise to ground. At the time KORT was aboput 75 watts transmitter power, I believe. We had a similar problem at Blaine AFS with Vacouver BC channel 12. A blanking strobe was developed to mitigate interference. As an airman deployed at Blaine 1965-1968 my specialty was transmitter/antenna maint. & repair. To the best of my knowledge this system did operate in the VHF region.

4. Power Output: As stated elsewhere, I believe the FPS-24 transmitter output power to have been 10 MW, at that time the most powerful radar transmitter in inventory except for the BMEWS. Please provide a reference to show otherwise and I will quietly fade from the scene on this issue.

5. 'Dome' versus 'radome'. This was a pretty nitpicky edit, I think, because the use of a protective dome over a radar antenna, whether it be on an FPS-24 or on a Boeing 767, has always been a 'radome'. A radome, obviously, is a protective dome that is *transmissive to the RF frequency of the radar*. In fact, it is this transmissivity that makes any old 'dome' specifically a 'radome'. Radomes are not just random layers of fiberglass, but are tuned to a frequency to achieve maximum transmissivity while still meeting the structural needs in an operating environment (a hurricane force wind with ice and sleet striking a radome with ice, lightning and rain striking the radome of an airliner at 470 knots airspeed, or an F-18 at Mach 2+, are other examples). The defining characteristic of radomes is the transmissivity to their operating frequencies. Thus, I believe 'radome' is the proper word to use in this context.

6. Two FPS-24 radar installations had the benefit of being covered by a fiberglass radome. One such installation was that at Cottonwood Air Force Station, Idaho. The other if I recall correctly was at Blaine AFS, Washington. I pitied the poor guys who had to work on that antenna deck without a radome in the midst of winter.

7. Caption change to 'FPS-6A'. Good catch. Thanks. LarryB55 (talk) 01:24, 26 November 2011 (UTC)

According to radomes.org, Mt Hebo AFS, Oregon (not as I have previously stated, Blaine AFS, WA) was the only site other than Cottonwood AFS to have an FPS-24 radome. LarryB55 (talk) 15:29, 27 November 2011 (UTC) Fortunately, for those of us at Blaine, WA (757th Radar Squardron) most rooftop work as AC&W techs only involved oil changes for the 4 large gear boxes under the sail. That could be bad enough in winter if the scheduled maintenance fell on those months.