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<br />,
<br />
<br />p08sibl~ scan rate of 207 PRF, averaging 128
<br />~~les over 0.50 elevation increment. This is
<br />done to insure that, if fewer samples or a
<br />faster PRF are desired, the antenna will not move
<br />too fast to properly sample the areas of concern,
<br />
<br />~e radar has two ide~tical magnetic tape .
<br />recorders. A recorder may be selected by the
<br />operator by depression of either the A or the B
<br />switch. The appropriate switch will light up if
<br />the selected recorder has been properly loaded
<br />with a magnetic tape and the recorder is in the
<br />REMOTE position. That light will stay on until
<br />the operator switches to the other recorder or
<br />until the 2,40o-ft tape is full and a switch
<br />automatically occurs. This automatic switchover
<br />precludes loss of data during recording.
<br />
<br />There are two ways of insuring data are being
<br />recorded. One is the Record Count display which
<br />is incrementally increased as the data are being
<br />recorded. The second way, and the one that per-
<br />mits checks of the quality of the data being
<br />written on tape, uses the "read after write"
<br />capability of the tape recorder. The RECORDER
<br />position of the Display Mode switch on the
<br />operator's console is selected, and the data
<br />displayed on the A-scope, PPI, and RHI will be
<br />those data that were'actually written on the tape
<br />for the previous 40 of azimuth. The scopes must
<br />be in the C-LOG or AVERAGE LOG position to be able
<br />to see these data in the "read after write" mode.
<br />
<br />The data being recorded may be completely inde-
<br />pendent of those data being displayed. Each
<br />scope has a 4-position Display Mode switch which
<br />will allow the operator to have displayed Linear,
<br />Logarithmic, Contoured Logarithmic, or Average
<br />Logarithmic video. The DVIP applies a STC func-
<br />_tion to the Contoured and Averaged Logarithmic
<br />ideo. This STC correction is added in 1/3-dB
<br />steps at the appropriate range between 10 and
<br />256 km. Recorded data are not range-corrected,
<br />but subsequent data processing introduces the
<br />correction.
<br />
<br />The range at which a signal return may be seen on
<br />the displays is controlled by the Range switch on
<br />each display. The three possible range~ are 125,
<br />250, and 500 km. The major difference between
<br />the data being recorded and the presentation on
<br />the scopes is the range. The distance at which
<br />the data are recorded is controlled by the Range
<br />Interval switch, the Range Delay, and the fixed
<br />number of range bins for data storage (250). The
<br />range delay can be preset from 0 to 99 km. The
<br />range interval switch can be 0.25, 0.5, 1 or
<br />2 km. Therefore, it is possible to select a 2S-km
<br />range delay and a O.S-km range interval, and data
<br />would be recorded from 25 km to 150 km. If the
<br />displays were in the l25-km position, not all of
<br />the data being recorded would be ~splayed, but
<br />this could be corrected by switching to the 250-
<br />km range. There is a default mode hardwired into
<br />the system to prevent selecting the 2-km range
<br />interval with a 414 PRF. The system automatically
<br />defaults to the 0.2S-km range interval. .
<br />
<br />The Air Traffic Advisory console is identical to
<br />the master console PPI but also has the controls
<br />for the L-Band IFF radar. Three sets of thumb
<br />wheel ~witches for selecting the transponder
<br />codes of the research aircraft (LearjetOn-Top
<br />Seeder, King Aire-Cloud Physics, and Navajo-
<br />
<br />e
<br />
<br />Cloudbase) to be recorded on tape are also
<br />located on this console. The range-bin loca-
<br />tion of aircraft number 1 is written in
<br />bin 251, number 2 is in bin 252, and number 3
<br />is in bin 253 (e.g., if aircraft number 2 is in
<br />range bin SO, a "50" will be written in
<br />bin 252). These range bins will have a zero
<br />value unless the appropriate aircraft is
<br />detected. It is possible to have a number in
<br />all three bins if the aircraft are in trail
<br />along the same radial.
<br />
<br />The IFF radar controls consist of an ON-OFF
<br />switch and a video intensity gain control for
<br />aircraft video. The IFF receiver uses a SHORT · .
<br />or LONG STC function. The SHORT position
<br />allows the receiver to have full gain at closer
<br />ranges to the radar, while the LONG position
<br />may eliminate aircraft close to the radar. All
<br />transponder-equipped aircraft within interroga-
<br />tion range of the IFF radar will be displayed on
<br />the air traffic advisory console PPI. If Con-
<br />toured Log video is being displayed from the
<br />master radar, two presentations, one of raw IFF
<br />video and one of contoured video, will appear
<br />for the aircraft which are transmitting on the
<br />selected codes. This assures that the aircraft
<br />video is being recorded.
<br />
<br />The radar has a PLAYBACK capability which allows
<br />one to read a recorded tape and display the data
<br />as they were viewed during the recording
<br />process. The cloud echo video, aircraft posi-
<br />tions, A and B PRF, Samples Average, range
<br />interval, ID code, Range Delay, Record count,
<br />azimuth angle, elevation angle, and clock data
<br />will all be displayed. The only noticeable dif-
<br />ference in PLAYBACK is that the sweep on the RHI
<br />scope does not move as the elevation angle
<br />changes.
<br />
<br />The system has a provision to allow coded mes-
<br />sages to be recorded in the header portion of
<br />the data record that is put on tape. This
<br />function is called the "Operator's Notebook"
<br />and has 17 coded messages plus a Time code in
<br />hours, minutes, and seconds. Each of the 17
<br />messages can be followed by a 6-digit number.
<br />This provides an almost unlimited number of
<br />messages that can be entered ,. but the practi-
<br />cability of remembering which message is asso-
<br />ciated with which code does, in fact, limit the
<br />system. Messages may be erased by depressing
<br />a reset button and starting again, This clears
<br />both the coded message and the 6-digit number.
<br />
<br />Sixteen coded messages and their numbers can be
<br />entered before the load storage register
<br />becomes full. Upon loading a 17th message or
<br />depressing the Load switch, the load storage
<br />register is copied to a write storage register
<br />and cleared. The messages will remain in the
<br />write storage until the initiation of the next
<br />3600 azimuth scan. The message will then be
<br />written to tape in succeeding headers of data
<br />recording. When the messages have been trans-
<br />ferred to the write storage register, the load
<br />storage register is available for 16 more
<br />messages. If these 16 entries are made prior
<br />to emptying the write storage register to tape,
<br />the system will not accept the messages.
<br />
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