Astro Digital Consent

1905-EX-ST-2018 Text Documents

FCL Tech, Inc.

2018-12-06ELS_220767

Bjornson, Christopher

From:                                        Bjornson, Christopher
Sent:                                        Thursday, December 06, 2018 1:46 PM
To:                                          ' Leann.Nguyen@fcc.gov'


Subject:                                     FCL Tech, 1905-EX-ST-2018




Ms. Nguyen:
You had asked FCL Tech to submit a written consent from Astro Digital for its operations in the 25.5-27.5 GHz
Band under the above-referenced STA application. Astro Digital has consented to the proposed operations
through the email below. Please let us know if you have any questions.
Sincerely,
Chris


Christopher Iì. Bjornson
Steptoe &.lohnson LLP
1330 Connecticltt ,¡\venue, N.W
Washington, D.C. 20036
Phone: 202.429.3059
e-mai I : cbj ornson@steptoe.com



From : Ja n King [ma ilto   :ja   n   @astrodigital.com]
Sent: Wednesday, November 28,20IB 1:05 AM
To: Bjornson, Christopher
Cc: peter.ruderman@astrodigital.com; Lin, Tony; Chris Biddy; Kyle Leveque; Gordon Hardman; Brian Cooper
Subject: Re: Request for Consent to Use the25'5-275'5 GHz Band

Christopher,

I   am Jan A. King, CTO at Astro Digital. I'm the direct AD staff person who handles most of the spectrum
regulatory analysis matters for our firm. I understand we are requested by the FCC to respond to you with
regard to coordination of your Ka-band links, being used for a low altitude airborne station demonstration, with
our Landmapper satellite system. We understand you will be using a STA, which has beeu hled by you with the
Commission. Our Landmapper system uses the 25.5 to 27 .0 GHz band for its high speed remote sensing data
downli¡k. We are authorized to do so under a Part 25 license issued to us by FCC.

I have reviewed the STA as requested by Peter Rudermau (which you forwarded to him and to rne) and I am
primarily reacting to the air-to-ground link in the frequency band 25.5 - 27 .5 GHz. From the Form 442 i
undelstand the following (l think it's always a good idea to check to see if I am interpreting what you are
intending, correctly)   :




The air-to-ground link has a TX power outpttt of 2.51W                   :   4.0 dBV/.

The emission bandwidth is 2.0 GHz

The 1X a¡te¡na beamwiclth is 6.5 degrees (HPBW), which yields an antenna with a directivity of 28.0 dBW
and a gain of 27 .0 dBW.

                                                                         1


This produces an airborne platforrn EIRP        :   4.0 + 27 .0 dBW   : 3l dtsW :   1259 Watts.

For this power to be received by a victim station, that station would have to be directing its beam toward the
airbome platforrn and the airborne platforrn beam would have to be directed toward the victirn grourrd station.

i¡ addition, for the victim to receive the emission frorn the airborne platform        above a 5 degree elevation mask,
that victim would have to be within 54 krn (slant range) of the airborne platform ernitter. This is correct for an
airborne platform at 5000 m and under smooth terrain conditions. We assume the LAT/LONG of the airborne
platforrn is nearly stationary and is either tethered or controlled by on-board means.

It is not worth considering                  victiln ground station has an elevation angle lower than 5 degrees
                                 cases where the
due to the excess path losses at26.5 GHz    caused  by meteorological conditions. For the record, the slant range
to the horizon (0 deg. elevation angle) at 5000 m altitude is 253 km.

The potential for interference, in this instance, would be from your airborne platform to our Earlh station, while
receiving a Landmapper satellite.

I'm pleased to inform you that our nearest (and only) Earth station for receiving our satellites at 26.8 GHz, at
this time, is located in Norway at Svalbard Island. That station is at 78.23 deg. N and 15.37 deg. E. It is at 479
m mean altitude. So, there could be no line of sight condition between our Earlh station and your airborne
platform.

So,   I   see no case   for interference between your airborne downlink and our Earth Station, if my interpretation of
your system is correct.




  Similarly, you have a ground-to-air link in the same fi'equency band and with the same emission
bandwidth. The EIRP value is much higher but, the ground station beamwidth is much smaller (and the gain
much higher). I have not analyzed this case but, I don't believe this is necessary. The only potential for'
interference would be from your ground staton to our ground station, which does receive in that frequency
band. However, as our station is at Svalbard, there is no possibility for interference from your ground station
either, so long as it remains in Southern California. I also see no other issues with this link pair insofar as the
Landmapper system is concerned, if my interpretation of you system is correct.

'We
   lrave no applications in process nor any license with any administration for the 38.0 - 39.5 GHz fi'equency
band. So, that band gives us no concern.

If you would  be so kind, while we have your Form 442 submission to the FCC, we would appreciate also
receiving a service copy of youl response to Question 6 of Form 442 (also sometimes referred to as your systenl
narrative). These applications interest us generally and we would like to remain informed regarding activities
in the mmW region of the spectrum. If you could pass this to Petel it would be helpful to us for our records.

Good luck with your trials and we would enjoy learning about any publicly available information regarding
your results. Let us know if we can be of any further assistance or if we have misinterpreted any of your F-orm
442 information.

Best Regards,

JanA. King
Chief Technical Officer
                                                               2


Astro Digital - US
ìanfÐ.astrodi sital.corn




        On   Nov 28,2078, at3:25 AM, Bjornson, Christopher <cbjornso@steptoe.com) wrote:

        <STA Application Form.pdÞ




                                                      J



Document Created: 2018-12-06 12:02:06
Document Modified: 2018-12-06 12:02:06

© 2026 FCC.report
This site is not affiliated with or endorsed by the FCC