Antenna Parameters for AeroSat HR6400 RF Subsystem

0013-EX-ML-2009 Post Grant Documents

HNS License Sub, LLC

2009-03-13ELS_96799

                                                                                                   Page 1 of 1




 Douglas Young

  From:          Steven Doiron [Steven.Doiron@hughes.com]
  Sent:          Thursday, March 12, 2009 11:01 PM
  To:            Douglas Young
  Cc:            Stephen D. Baruch; Scott Kotler; James Burtle; David S. Keir
  Subject:       RE: Antenna Parameters for Experimental Radio Station WE2XEW
  Attachments: OET Response.pdf

Please see the attached file.

Regards

Steven Doiron
Senior Director, Regulatory Affairs
Hughes Network Systems
301-428-5506




From: Douglas Young [mailto:Douglas.Young@fcc.gov]
Sent: Friday, February 06, 2009 3:11 PM
To: David S. Keir
Cc: Stephen D. Baruch; Steven Doiron; Scott Kotler; James Burtle
Subject: Antenna Parameters for Experimental Radio Station WE2XEW

On October 22, 2008, HNS License Sub, LLC ("Hughes") notified the FCC that Hughes had
commenced operation of mobile satellite antennas permitted by the license granted for file no. 0100-EX-ML-2008
using an r.f. carrier not specifically listed in the authorization. Hughes also stated that in accordance with
47CFR5.77(b), the change in emission will not exceed the maximum emissions envelope authorized in the
license. In order to assure compliance with the authorization, we request that Hughes provide the maximum
antenna flange input power in any 4 kHz band (in dBW/4 kHz) and the associated antenna manufacturer and
model that together demonstrates that the maximum EIRP density in any direction (azimuth and elevation
planes) does not exceed at any time the emissions envelope authorized in WE2XEW for each antenna that was
not specifically listed in the application.


Doug Young
Electronics Engineer
Federal Communications Commission
Experimental Licensing Branch
Phone: (202) 418-2440
Fax: (202) 418-1918
Email: Douglas.Young@fcc.gov




3/13/2009


March 12, 2009


Dear Mr. Young,

    In your email dated February 6th, 2009, you requested that HNS License Sub, LLC
(Hughes) provide the maximum antenna flange input power in any 4 kHz band and the
associated antenna manufacturer and model that together demonstrates that the maximum
EIRP density in any direction (azimuth and elevation planes) is always within the
emissions envelope authorized under Call Sign WE2XEW for each antenna not
specifically listed in the application. In this response, Hughes demonstrates that the EIRP
radiated by airborne terminals being developed by our partner, Row 44, Inc. (Row 44),
complies with the authorization granted Hughes by OET.

Authorized Levels:

       In 2005, General Dynamics obtained an experimental STA1 in order to validate
the operation of a satellite terminal mounted on the roof of a HMMVW or other combat
vehicle. A critical part of this terminal is a gyro-stabilized antenna that is necessary for
keeping the antenna pointed towards the satellite while the vehicle is in motion. In 2006,
Hughes requested a similar experimental STA in order to conduct separate tests with its
own test vehicle.2 This vehicle was and remains equipped with a gyro-stabilized General
Dynamics antenna system and a Hughes satellite modem so that it can communicate with
Hughes’ VSAT gateway. With the success of this test program, Hughes decided to
continue its test program and consequentially applied to have its experimental STA
converted into a permanent experimental license.3

        In response to customer requests and market developments, Hughes has made
multiple modifications to its experimental authorization in order to add different antenna
models, to increase the number of testing locations, to allow testing on sea vessels, to
allow testing in Ka band, and most recently to allow testing of airborne platforms. While
the authorization has been expanded multiple times, the technical characteristics
underpinning the application are still based on the original General Dynamics antenna
and these parameters are summarized in Table 1.




1
  OET File Number 0640-EX-ST-2004 (Call Sign WC9XAP).
2
  OET File Number 0207-EX-ST-2005 (Call Sign WC9XET).
3
  OET File Number 0011-EX-PL-2006 (Call Sign WE2XEW).


                                             1


                             TABLE 1 – GD Terminal
                    Antenna Manufacturer        General Dynamics
                   Antenna Model Number            S825-1100
                      Antenna Diameter               60 cm
                       Boresight Gain               36.8 dBi
                 Antenna Off-axis performance Does not meet 25.209
                                                   (by 9 dB)
                    High Power Amplifier            15 Watts
                         Peak EIRP                 48.6 dBW
                      Carrier Bandwidth       1.6 MHz (1M60G7D)


        The current authorization obligates an EIRP density of 13.5 dBW / 4 kHz in order
to ensure that the terminal complies with the off-axis EIRP limits for VSAT terminals.4
As the antenna transmit gain is of 36.8 dBi, this EIRP density value of 13.5 dB
corresponds to a power density at the flange of -23.3 dBW/4kHz. This value is of 9 dB
less than the maximum flange power density that can be routinely authorized by the FCC,
in order to compensate for the non-compliance of the antenna with the off-axis antenna
gain mask.5

         As a consequence, the existing authorization allows an on boresight peak EIRP
of 48.6 dBW, an on boresight EIRP density of 13.5 dBW/4kHz and an off boresight EIRP
density compliant with 25.134(g).

Row 44 Terminals

         In partnership with Row 44, an airborne communication architecture was
developed by Row 44 and Hughes consisting of Hughes gateways, Hughes satellite
modems and an antenna system designed by AeroSat. So as to be able to test this system
as well as other airborne systems that Hughes might develop, Hughes requested authority
to test airborne terminals under its OET authorization.6 Hughes subsequently further
modified its license under Call Sign WE2XEW to enable Row 44 to conduct limited
market studies under Section 5.93 on several commercial airplanes.7 Separately and in
order to bring the developed system to the marketplace, Row 44 applied to the FCC’s
International Bureau for both an STA and a permanent license.8

      In its applications for a Part 25 license and STA, Row 44 identified the technical
parameters included in the following table.




4
  OET File Number 0013-EX-ML-2009 (Call Sign WE2XEW) Condition 11.
5
  CFR Title 47 Part 25.134 (g)
6
  OET File Number 0100-EX-ML-2008 (Call Sign WE2XEW).
7
  OET File Number 0013-EX-ML-2009 (Call Sign WE2XEW).
8
  FCC IB File Numbers SES-LIC-20080508-00570 and SES-STA-20080711-00928.


                                             2


                            Table 2 – Row 44 Terminal
              Antenna Manufacturer                    AeroSat
              Antenna Model Number            HR6400 RF Subsystem
                                        (includes antenna 70-100-0000-01)
                  Boresight Gain                     28.6 dBi
                 Antenna Off-axis             Complies with §25.209
                 gain performance
               High Power Amplifier                  10 Watts
                Peak power density                -14 dBW/4 kHz
               at the antenna flange
                Carrier Bandwidth               1.6 MHz (1M60G7D)


       These parameters show that the Row 44 terminal meets both the off-axis antenna
gain mask as well as the antenna input flange power density specified in the FSS’s rules.
As a result, the antenna complies with the off-axis EIRP mask necessary for routine
processing which is also the case for the General Dynamics terminal.

        Furthermore, with a boresight gain of 38.6 dBi and a peak flange power of 10
Watts, the peak EIRP is of:

                                     EIRP = P + GT

                                  = 10 dBW + 28.6 dBi

                                   = 38.6 dBW/4 kHz

This value is 10 dB less than the peak EIRP authorized for the GD terminal.

       However, for the EIRP density on boresight, the value is of:

                                    EIRPo = Po + GT

                              = -14 dBW/4 kHz + 28.6 dBi

                                   = 14.6 dBW/4 kHz


which is one dB greater than the value indicated in Hughes authorization. In order to
comply with the Hughes experimental authorization, Row 44 has selected a power
density level that is slightly reduced from its requested operational configuration.

As a result of this slight reduction, the Row 44 terminal operates with an on boresight
EIRP of 37.6 dBW, an on boresight EIRP density of 13.5 dBW and an off boresight EIRP
that is 1 dB less than the EIRP mask established for routine licensing.



                                            3


Conclusion

                                       Row 44                WE2XEW
          on-axis EIRP                37.6 dBW                48.6 dBW
          on-axis EIRP density    13.5 dBW/4 kHz         13.5 dBW/4 kHz
          off-axis EIRP density One dB better than          Just meets the
                                 off-axis EIRP mask     off-axis EIRP mask
                                for routine processing for routine processing

The foregoing clearly demonstrates that the on-axis EIRP, on-axis EIRP density as well
as the off-axis EIRP density for the Row 44 terminal is within the levels authorized under
Call Sign WE2XEW.

Yours truly,




Steven Doiron
Senior Director, Regulatory Affairs
Hughes Network Systems
11717 Exploration Lane,
Germantown, MD
20876




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Document Created: 2009-03-13 08:01:51
Document Modified: 2009-03-13 08:01:51

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