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Ground Measurements The System
The vehicle is equipped with a 42' or a 29' pneumatic mast depending on requirements. The log periodic antenna is mounted on a rotor to obtain the maximum signal level in the transmit direction. The rotation of the antenna also aids in the location of multi-path and other interference issues. The antennas that are employed consist of tuned dipole, log periodic covering from 25MHz to 1GHz, and selected and measured vertical antennas. The overall system is powered by the Z-Technology products that employees GPS tracking with time and date stamps along with the location of each measurement. The logging method permits continuous operation throughout the covered area monitoring thousands of points. Each frequency measurement is "characterized" for gains and attenuation of the system and is contained as part of the logged readings permitting verifiable results and accuracy. On a point to point measurement spectrum analysis is part of the program and can also be part of the logged record. These visual reading are transferred to Power Point or MS Word documents with notations. The system operates on a continuous run or point to point measurement depending on measurement requirements and desired results.
The following are spectral displays.
The active cursor is placed to indicate the measurement of the NTSC signal as noted in the lower right hand corner of the picture while the other markers are set to measure the energy values of the ATSC signal. The digital is the primary measurement in this instance. You can also note the digital "hash" on portions of the NTSC carrier. This is a N+1 assignment. The channels are 50,51, and 52 respectively. The gray cursor is measuring the integrated power of the digital signal. This is only one sample of testing available from the advanced equipment we utilize. These references provide extra proof and visual indications of sample taken at specific locations. When documents are prepared these add further verification to the sample data. The lower photo is from the logging screen and is placed with the spectral graphic to support data.
Once the data collection is complete the map is prepared as a dot plot. The map portion on the right is an expanded view of the the multiple samples taken at one point. Later the map on the left will be tagged with note files indicating average readings and elevation along with any special information about the location.
Each of the dots indicate a signal sample point, reading averages from the compiled "drag test" sample, and elevation. The time and date are included in the report and not needed on the map. During the observation phase of each sample location notes are added to indicate any man made obstruction and possible future problems. The database is independent of the map software. As new map software becomes available the customer can update the samples to new maps if desired. The documents are printed and put in final order for presentation. Along with a finished notebook which includes a CD ROM with all data, current map software used during the test, printed material, and a power point presentation.
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720.220.7875 / jdb@dbkcom.com
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