Globalstar Product Management – Technical Support

Anritsu MT8803G Required to Test Globalstar Duplex Communication Products for Compliance with FCC 47CFR 2.1053 & 25.202(f)

The Anritsu MT8803G is test equipment required for demonstrating compliance with FCC Regulations 47CFR 2.1053 & 25.202(f)


The Anritsu MT8803G is required when testing Globalstar duplex communication products against FCC regulations 47CFR 2.1053 and 25.202(f).

Applies to:

End-user Products which utilize the GSP-1720, GSP-1620, GSP-2900 or any other Globalstar duplex product


For an end-user product (a.k.a. Equipment Under Test, a.k.a. EUT) which includes a Globalstar duplex modem or phone, FCC regulations 47CFR 2.1053 and 25.202(f) require that the Part 25 Spurious Emissions (SE) be measured while the EUT is in its normal operating mode, representative of worst case conditions.  For a Globalstar duplex transmitter (e.g., GSP-1720), the “worst case” conditions will be achieved when the transmitter is engaged in an active satellite-mode call, transmitting data, and operating at maximum power.  The Spurious Emissions measurements must be made at several frequencies within the range of allowable transmit frequencies of the device.

The test requires no modifications to the Globalstar phone/modem.  Minor EUT software modifications are sometimes required in order to set up the satellite phone call or to turn off EUT power-saving modes or to disable any limitations which have been programmed into the EUT to limit call length:

  • Place the EUT in an active call, in either “Voice Loopback” or “Markov” mode (Transmit mode)
  • Configure the MT8803G to command the phone to its maximum transmit power
  • Measure the Spurious Emissions while the EUT is transmitting at maximum power at the following frequencies (at least):
    • Low Channel (e.g, channel 1)
    • Middle Channel (e.g., channel 3 or 6)
    • High Channel (e.g., channel 6 or 9)

The Anritsu MT8803G is required for this test because it is the only commercially available piece of test equipment which is capable of:

  1. engaging Globalstar duplex transmitters in a satellite mode call
  2. commanding the Globalstar phone/modem to transmit at specified a specified frequency
  3. commanding the Globalstar phone/modem to transmit at a specified power level

NOTE regarding Conducted Measurements:

In addition to the radiated measurements, virtually all Class I Permissive Change Spurious Emissions (C1PC SE) reports that we have seen also include measurement results for conducted power, in accordance with CFR47 2.1046 & 25.204.  Regulatory labs have explained that even though the conducted measurements are not required for the FCC C1PC report, they consider it essential to carry out conducted measurements prior to measuring Spurious Emissions, in order to confirm that the Globalstar transmitter in the EUT is transmitting at the nominal power levels expected (and as reported in the original FCC filing for the Globalstar transmitter).  If the measured transmit power is out-of-bounds, the lab halts testing and does not collect Spurious Emissions measurements because the measurements would not be representative of a production EUT.   This is an extremely rare occurrence, but regulatory labs are usually conservative in their expenditure of time, and therefore they virtually always carry out this simple test.

Labs that have carried out the conducted measurements have included these measurements in the C1PC report.  The laboratories believe measurement of the conducted power is a prudent and necessary prerequisite to their SE measurements in order to ensure themselves, the client, and any future auditors that subsequent SE measurements are valid.  Our understanding is that inclusion of these measurement results in the C1PC report adds little or no cost to the SE measurement project since the measurements are being done anyway, so it is just the cost of writing the few paragraphs and including some plots.  The rationale of the laboratories has been that, although measurement of conducted power is not required by the FCC, it provides the client with additional assurance and additional information which could be helpful in the case of a future FCC audit.

The Anritsu MT8803G user manual and a quick-start guide for MT8803G-assisted FCC measurements are available at:

Globalstar may be able to provide assistance if a laboratory has a temporary need for an Anritsu MT8803G.

Please direct any questions or comments to:

Joseph Crowley
Manager, Advanced Products & Services
Globalstar, Inc., 461 S. Milpitas Blvd, Milpitas, CA  95035
Email:             Phone: +1.408.933.4433

Written by Joseph Crowley

August 23, 2017 at 3:13 pm

Posted in Uncategorized

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