Checking RF Signal Quality

When and where to use:

This check must be performed with one channel at each site. The objective is to document received signal quality. By keying up a channel at each site with a 1 kHz test tone and checking the SINAD, you determine if the test antenna and optimization receiver are adequate for performing the simulcast subsystem optimization.

Procedure:

  1. Configure the Service Monitor to make SINAD measurements.
    • If using a service monitor as the optimization receiver, set the SINAD meter input to the demodulated signal. Set the service monitor so that external audio is the source for the SINAD meter.
    • If not using the service monitor as the optimization receiver, temporarily connect the optimization receiver audio output to the audio input of the service monitor.
  2. Using either the TenSr channel bank or the MLC 8000 Configuration Tool, key-up a channel at the site nearest the optimization receiver (may be co-located) with a 1 kHz tone. (See Performing Fine Amplitude Adjustment for circuit-based systems or Performing Fine Amplitude Adjustment for IP-based systems for instructions on how to key-up).
  3. If using the service monitor as the optimization receiver, check the Analyzer RF level. If it is greater than 0 dBm, de-key the transmitter (click the Stop button) and insert enough attenuation so the level is less than 0 dBm and then re-key (click the Start button). If the RF Level is below ~-60 dBm, turn on the RF pre-amp if one is available.
  4. Use the SINAD meter on the Service Monitor to evaluate the quality of the received signal. A minimum SINAD of 10 dB is required with a DSA to produce stable tone levels.
  5. De-key the channel under test and key-up the same channel at each of the different sites, one at a time.
  6. Check the Service Monitor for better than 10 dB SINAD.
  7. At the end of this process, you should have an acceptable SINAD for each site.
  8. If you cannot obtain an acceptable SINAD, do not proceed with the optimization. Identify the issues preventing acceptable readings and correct them.

Postrequisites:

Perform either the circuit-based or the IP-based procedure that follows depending upon your system configuration.