JHUAPL: Satellite Communications Facility

JHUAPL: Satellite Communications Facility JHUAPL logo

60-Foot (18.3-Meter) System

60-Meter System

Downlink S-band X-band
Frequency Range 2200-2400 MHz 8400-8500 MHz
Polarization Simultaneous RHC and LHC Simultaneous RHC and LHC
G/T >28.3 dB/K >38.5 dB/K
Beamwidth 0.5 deg 0.13 deg
Uplink S-band
Frequency Range 2025-2120 MHz
Polarization “On-the-fly” Selectable LHC or RHC
Beamwidth 0.5 deg
EIRP >80 dBW
Transmitter 2000 W Klystron (dual redundant)
Antenna Pointing Control
Program track (TLE, Spice-SPK, Chebychev, RA/DEC), S-band Autotrack, S/X-band Steptrack
CCSDS Compliant
Command, Ranging, Doppler & Telemetry, including Turbo (r1/2, 1/3, 1/4, 1/6), Convolutional (r1/2), Reed-Solomon, and Conv/R-S; Wide variety of modulation formats; Space Link Extension “SLE” (Fwd CLTU, RAF, & RCF services)

5-Meter System

5-Meter System

Downlink L-band S-band X-band
Frequency Range 1650-1750 MHz 2200-2300 MHz 8000-8500 MHz
Polarization RHC RHC RHC
G/T >11.2 dB/K >13.6 dB/K >24.1 dB/K
Beamwidth 2.5 deg 1.8 deg 0.5 deg
Antenna Pointing Control
Program track (TLE, Spice-SPK, Chebychev Polynomials. RA/DEC)


Sources: TWT-1-009 8 April, 1963 E. F. Snyder
Johns Hopkins APL Technical Digest, Jan. – Mar. 1998, V19#1
Photo Archives of the Satellite Communications Facility


As a result of the success of the early work done for the Navy on the concept of satellite based navigation, the Transit Program was about to become a reality. Two ground stations would need to be constructed to support the continuing work as the program headed toward an operational system.

By the 15th of November, 1962 Work on the APL Station had already begun. The first foundation, a donut shape had been determined to be inadequate and subsequently destroyed. A second foundation, approved by APL engineers was now entering the first phases of construction.

This second foundation is a rooted structure with 20 poured, steel reinforced concrete pylons 35 feet deep. Eight of the 20 pylons are drilled holes 48 inches in diameter, loaded with a welded steel reinforcement cages followed by poured concrete. The remaining 12 pylons are 14 inch diameter driven piles filled with poured concrete.

A total of more than 500 cubic yards of concrete are contained in the foundation with an estimated weight in excess of 2 Million pounds.

November 15, 1962

Drilling Hole #1 of the foundation
(notice Building 36 and several pylons in the background

Drilling Hole #8 of the foundation
(Also visible in the background, the helix antennas on Bld. 36)

Lifting a 35 foot long 3 ft. diameter Reinforcment cage into the hole.