Living with your license


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Your new or latest license has arrived. How you deal with it can have a huge effect on your future. The first and most important thing that you should do is make several copies of the license. I also like to make a note on the back of the license itself showing the date on which I received it. This license will tell an FCC inspector the conditions under which the transmitter and antenna system should be operating. If, in addition to this license, the station also operates under an STA or any other authorizations, be sure that it or a copy of it is attached to the license. The license and other authorizations should then be safely mounted in a frame or placed in a binder and clearly displayed at the control point.

The parameters on the filed Form 302 establish the basis of a station’s operation.

Place a copy of the license in your engineering file (for DA operation, attached to the engineering copy of the final proof report) and another copy in your license file. It's also a good idea to put one in the public file. From now on the station's operating parameters should closely resemble the values in the engineering proof of performance, the figures contained in Form 302 and the Application for Station License. The only safe way to operate at variance from licensed values is to have an authorization, from the Commission, that is associated with the license.

It is probable that some time has passed since you originally filed Form 302 to apply for the station license and submitted engineering information on the station' s operating parameters. Given that human nature being what it is, it is also probable that no one has paid much attention to checking the operating parameters regularly. A station can be inspected soon after a license has been issued and it is not a good idea to start with a violation notice.

Carefully inspect the whole of the transmitter/antenna installation to make sure that the system is operating in accordance with its license and also to gain an idea of its stability. In the case of a non-directional antenna, operating base current (assuming that base operating resistance is stable) will be the critical figure to check. This should, of course, be within the limits based on Form 302. If this is correct and the base operating resistance hasn't changed it is usually safe to assume that the RF power is correct.

I like to compare RF power (I2ant × Rant =P) against the final stage dc power (Ianode × Eanode =P) to check efficiency.

The final stage efficiency is given by PRF/PDC × 100. It should be close to the original efficiency factor of the transmitter. Provided that all the other meter readings are normal it is safe to assume that you are in compliance with your license. If you ever have to operate on indirect power measurement you will need this efficiency figure.

If the efficiency is not close to the original efficiency something has changed. It's probably too close to the date since the original testing for final tube emission to have decreased significantly. Now is the time to double check the whole transmitter/antenna system for significant changes.

Confirming directional antenna operation compliance

In the case of a directional operation, if the antenna monitor readings agree with the licensed values and the common point current and antenna monitor phase and ratio indications are also correct FCC monitor point readings should be taken. Be sure that the field strength intensity meter is still within its calibration period. If the monitor point readings also fall within the license limits and there are no unusual meter readings it is safe to assume that you are operating in accordance with the terms of your license.

Depending on the station frequency and the operating range of your FIM it's a good idea to make a final check on as many main carrier harmonics as possible. We know this should have been checked earlier, but sometimes non-linear rectifier situations do occur as equipment settles and unwelcome harmonics can develop. This is the time to make sure that you really are complying.

When checking the overall transmitter efficiency on a directional system, the common point current and common point impedance are used. Remember that the FCC allows a small percentage loss to the transmitter power depending on the licensed power.

When you are satisfied that the licensed operating parameters have been achieved and the station is operating as licensed, the phasor dial readings should be recorded in a log book together with the date and time. They should also be displayed on the phasor cabinet front in a safe and obvious manner adjacent to the respective controls.

Similarly, antenna monitor phase and ratio parameters should be displayed adjacent to the antenna monitor together with their plus and minus limits. When calculating these limits also calculate the limits, plus and minus, for the common point current and label it on the front of the phasor cabinet close to the common point meter.

If the tower is lighted confirm that the lights work properly and that the flasher is operating correctly. Tower paint color must satisfy FCC/FAA requirements. Confirm that the fences around the bases of the towers satisfy FCC requirements, and the gates are properly locked.

Ensure that the site is properly marked with RF radiation warning signs and the required FCC tower registration number and owner contact information are correctly displayed.

This may sound like a lot of repetitive work. However, your company probably spent a lot of money on the application for the new station or upgrade, as well as new equipment. Every station engineer who is responsible for the operation and maintenance of the transmitter/antenna system is also responsible for ensuring that the station operates in complete accordance with the terms of its license. It is also vitally important for professional considerations that a paper trail to management be maintained so that when problems arise the finger can be pointed at the right person.


E-mail Battison at batcom@bright.net.




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