TalkBack Losses
Q: When I computed my field strength study I included body and building losses for the mobile receiver. How do I include these losses in the TalkBack study?
A: Including these losses is an important part of evaluating the coverage of your base station or repeater. You can also include the losses in the talkback calculations based on that study.
Note that all values shown in this article are for illustration purposes only. It is important that you use good engineering judgment to determine the values that are appropriate for your equipment and specific application.
As explained in the article about setting values for body or building losses when computing required field, the Mobile Facility database is used:
Then in the Receiver Losses section, enter the losses for the receiver portion of the mobile unit::
Likewise, when you are setting up the transmitter portion of the mobile record (for the TalkBack study) you can include loss values. The transmit losses for the TalkBack study may be specified differently from the receiver losses. For an example, see the TalkOut and TalkBack Comparisons article. Be sure you also include the mobile transmitter information for the TalkBack calculation.
Then enter the desired loss values for the mobile transmitter:
The loss values you enter for the transmit and receive functions of the mobile unit may be the same, but TAP also gives you the flexibility to use different values to represent different configurations. For example, you may want to assume worse conditions for the TalkOut study (higher loss values for the mobile receiver). This would represent the situation where a handheld radio was lying on the seat of a vehicle. However, when the user picks up the unit, holding the antenna vertically, near the window of the vehicle, you may want to represent the TalkBack situation (mobile transmitter) with lower loss values. As always, you need to determine the best way to represent your particular circumstances.
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Copyright 2004 by SoftWright LLC