tv Station power vs time.

• For each measurement the sum of the 6 Mhz tv band is computed.
• The min, max, mean, and median values for the 74 sums of a day are computed and then plotted.
• Year to date and yearly plots are made.

    Some things to be aware of:

1. Each hilltop monitoring band has a different tsys and gain. The plots include these values. At the bottom of each plot are two dashed lines.
• The black line is the minimum power in the band for the day.
• The red line is the median power in the band for the day.
Use these lines to check whether the power in the band is changing. They are integrated over 100Khz rather than the 6Mhz of each tv station.
2. When the red and black dashed lines go to zero, there is no rfi monitoring data.
3. Leakage between channels. Tv stations are spaced by 6 Mhz. For strong tv stations there is leakage between channels in the spectrum analyzer. If you see adjacent channels moving together then this is probably the reason. The channel with the higher power is the channel that is resposible for the power.
4. The spectrum analyzer on the hill may be off in frequency by up to .6 Mhz. This will also mix stations a little.
   
5. When the 430 Mhz transmitter is on, many of the hilltop monitor bands saturate. When you see many tvStations moving together, this is probably the reason.
6. If a tv station jumps around a lot in the median power plot, look at the mean or max power plot. The station is probably turning on for half a day and the median is alternating between catching the on and off power levels.

Tv channel frequencies.

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