E-Mail generated [Aug 28, 2003]

0258-EX-ST-2003 Correspondence

Advanced Navigation & Positioning Corp.

2003-08-28ELS_62715

To: Matt Hederstrom
E-Mail: mhederstrom@anpc.com
From: John Kennedy
Date: August 28, 2003

Subject: FCC File #: 0258-EX-ST-2003
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Message:

Dear Mr. Matt Hederstrom:

The following are comments were made concerning STA file number 0258-EX-ST-2003:

" While the Transportable TLS design specification that was provided by Advanced Navigation
and Positioning Corp. did contain a great deal of information on the Transportable TLS, the
requested detailed technical description of the differences between the Transportable TLS and
the civil TLS system and proposed final configuration for the Transportable TLS were not
included in the specification.

First, the TLS 1030 MHz interrogation rate is specifically capped at 10 Hz and this results in 2.5
times the number of interrogations per aircraft that a conventional 1030 MHz ATCRBS
interrogator produces in the 120 degree mainlobe of the TLS 1030 MHz antenna. The proposed
Transportable TLS increases the number of interrogations over the maximum authorized for a
TLS system resulting in an increase in the number of interrogations to a minimum of 18 Hz with
no cap. Second, the Transportable TLS also includes an unacceptable interrogation from an
omnidirectional antenna. Third, the Transportable TLS adds Mode C interrogation capability
over the Mode A only interrogations of the TLS. It is unclear if the Mode C interrogations will
be in addition to the minimum of 18 Mode A interrogations proposed for the Transportable TLS.
Fourth, the proposed ERP of the Transportable TLS 1030 MHz transmitter (1700 Watts)
exceeds the maximum allowed ERP of the TLS system (1035.5 Watts) by 664.5 Watts. The
Civil TLS system has the same range and altitude volume as the Transportable TLS so use of
the additional powers is not justified. Fifth, the ERP's of the other Transportable TLS
transmitters are also in excess of those used on the Civil TLS system without any justification.
Sixth, the Transportable TLS specification does not clearly define the number of localizer (108-
112 MHz) and glide slope (328.6-335.4 MHz) frequencies the Transportable TLS will use in the
final configuration. FAA can not support the use of multiple localizer and glide slope
frequencies in a TLS system. Finally, the FAA can not support 360 degree surveillance using a
TLS type system as the interrogation rate seen at the aircraft exceeds the rate produced by
rotating 1030 MHz interrogators. Proper performance of all existing 1030 MHz interrogators
relies on maintaining low interrogation rates. The FAA is spending large amounts of money to
reduce the numbers of interrogations transmitted from FAA systems so that the TLS 1030 MHz
interrogation rate of 10 Hz is 8.333 times the number of interrogations per aircraft of that of the
newest FAA monopulse interrogators.

In summary, there are a number of issues that the FAA can not support in the proposed
Transportable TLS system. Therefore, the FAA still objects to the STA request. "

Please indicate in your response to this e-mail if you intend to pursue obtaining this STA or if
you wish to cancel this application.

The items indicated above must be submitted before processing can continue on the above
referenced application. Failure to provide the requested information within 30 days of
August 28, 2003 may result in application dismissal pursuant to Section 5.67 and forfeiture of
the filing fee pursuant to Section 1.1108.

Document Created: 2003-08-28 10:45:04
Document Modified: 2003-08-28 10:45:04

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