This is an attempt to unscramble the maze of accounts the page author has encountered concerning the August 13-14, 1956 RADAR-Visual UFO case at Bentwaters and Lakenheath air bases, in England. The following chart attempts to correlate the various accounts. Note that each sighting could have a different cause, and may be unrelated to any of the other sightings. The separate sightings are identified by [number]

The Sightings:

(L) The Evaluation:

Now that was a confusing jumble of accounts! Here is a list of observations the page author made, to try to reduce this down to something sensible:

(L) Notes about RADAR:

Here is a look at what really happens in a RADAR set of 1956 vintage. The sequence of events given is for one single pulse sent out by the transmitter:

  1. The blanking circuit locks off the electron beam in the display tube, and the receiver input is muted to prevent damage during transmitter operation.
  2. The sweep circuits return the electron beam position to the center of the display tube.
  3. The transmitter sends out the pulse. It moves away from the RADAR antenna at the speed of light (186000 mi/s or 300000 km/s).
  4. The sweep circuits start moving the electron beam away from the center of the display in the direction the antenna is pointing.
  5. The receiver is enabled, and the blanking circuits enable the electron beam.
  6. As the sweep moves away from the center, the weak electron beam leaves the visible line that is seen to be slowly rotating around the tube as the antenna rotates.
  7. The transmitted pulse strikes a target (if present), and part of it is reflected back to the antenna. The time it takes for the pulse to make the round trip determines the distance from the RADAR set.
  8. The receiver picks up and amplifies any returning echo (if present).
  9. If the MTI is on, the echo is amplified further and clipped, then fed to a gating circuit that decides whether or not an echo is there.
  10. The resulting signal is fed to the display driver. If the MTI is on, the signal is also fed to the mercury delay line. The delay line is adjusted to delay any signal fed into it for exactly the time between transmitter pulses.
  11. The display driver strengthens the electron beam in the display tube whenever it receives an echo signal. If the MTI is on, a delayed echo from the previous pulse will shut off the electron beam for an instant, canceling out any echoes received at the same location as the delayed echo.
  12. The strengthened electron beam makes a much brighter spot on the display tube. The brighter spot persists much longer on the slow-decay phosphor coating than the weak sweep line does. It will usually persist for several rotations of the antenna before the phosphor loses all of its energy.
  13. Any further echoes received by the antenna are handled in the same way as the electron beam continues to move out toward the edge of the display tube.
  14. During all of this, the antenna and the sweep coil have rotated a very small fraction of a degree.
  15. When the beam reaches the edge of the tube, the whole process repeats. Any echoes from the pulse just transmitted that are received after this point are treated as though they came from the next pulse. These are called second-trip echoes. Those received after several pulses have been sent are called multiple-trip echoes.

Thus, the RADAR set determines the location of an object by using two values: The direction the antenna was pointing when the echo was received, and the time since the last pulse was transmitted. Of course, extraneous signals, such as those abnormally ducted from distant RADARs, second-trip and multiple-trip echoes, multiply reflected echoes, and electronic noise can also be displayed just as though they were valid echoes. The MTI clipping and gating makes these spurious signals seem as strong as real echoes from planes. A misadjusted AGC can amplify these effects.

(L) Conclusions:

Here are the conclusions drawn from the above evaluations:

  1. The initial high-speed sightings were probably Perseid meteors. The date corresponds with the maximum meteor frequency.
  2. Most of the RADAR sightings were anomalous propagation, amplified by the MTI and AGC circuitry.
  3. One important thing to note: The RADAR sightings at Bentwaters were quite different from the ones at Lakenheath.
  4. Most of the visual sightings were single lights. Many of them could be airplane lights, including the planes sent to look for the UFOs.
  5. The RADAR sets were recently retrofitted with MTI and AGC.
  6. The whole case seems to be the result of unfamiliarity with the newly installed MTI and AGC, failing to correlate with other stations, failure to take good data at the time of the sighting, panic caused by the thought of UFOs (or Soviets), and a compounding of unrelated events occurring on the same night into one case.