Out of this World Antenna Measurements · –Crew phone patches with Family –Special propagation experiments –Ham ATV experiments. 2014 July 9 KE4PT slide 5 STS-80 STS-71 STS-65

Out of this WorldAntenna Measurements

SAREX Behind the Scenes

2014 July 9Kai Siwiak, KE4PT

prepared for the

2014 July 9 KE4PT slide 2

Part – I: Antenna Ranges

pager

30 meters signal source

transmit antenna

Typical OATS antenna range: Typical indoor anechoic range:

… In a river bed in China … in Boca Raton, Florida


Part – I: Antenna Ranges

pager

30 meters signal source

transmit antenna

Typical OATS antenna range: Typical indoor anechoic range:

… In a river bed in China … in Boca Raton, Florida

… the way Hams did it with NASA’s help


Background: SAREX (now ARISS)

• In the Public Eye– Random contacts with Hams World Wide– Contacts and Educational activities with schools and

youth groups– Visibility for NASA

• Behind the Scenes– SAREX support for missions and new capabilities– Crew phone patches with Family– Special propagation experiments– Ham ATV experiments


STS-80STS-71STS-65STS-58

STS-931999STS-94STS-831997

STS-81STS-79STS-78STS-761996STS-74STS-70STS-67STS-631995

STS-64STS-60STS-591994STS-57STS-56STS-551993STS-50STS-47STS-451992

STS-371991STS-351990

STS-61ASTS-51F1985STS-91983

MissionYear

More details : http://ct1eat.no.sapo.pt/sarex/sarexm_e.html

ColumbiaChallengerAtlantis DiscoveryEndeavor


SAREX Started After STS-9

Chuck, W4ROA

Kai, KE4PT Owen,

W5LFL Harold, KT4XK


SAREX Kick–off MeetingKai, KE4PT

Owen, W5LFL

Tom, K4GFG

Harold, KT4XK

George M,Motorola PR


top, left to right … Lou, W5DID, [SAREX P.I.]Kai, KE4PT, [Volunteer]Owen, W5LFL, [Astronaut]

Kai on OV-102 Columbiawith STS-9 antenna


…The cast included hundreds!


STS-71STS-65STS-58

STS-931999STS-94STS-831997

STS-79STS-78STS-761996STS-74STS-70STS-67STS-631995

STS-64STS-60STS-591994STS-57STS-56STS-551993STS-50STS-47STS-451992

STS-371991STS-351990

STS-51F1985STS-91983

MissionYear

More details : http://ct1eat.no.sapo.pt/sarex/sarexm_e.html

COLUMBIAWindow Antenna Gain Test


The Experiment

• NASA asked Hams to measure gain of SAREX window antenna

• Motorola-ARC and IBM-ARC responded with detailed measurements

• Many Hams sent signal reports

2014 July 9 KE4PT slide 12Source: QST Oct 1993 p53-55

Mor

e C

ast

Mem

bers


Space Lab Module on Columbia

Space Lab D2 antenna

[old STS-9 antenna]

SAREX antenna

source: http://en.wikipedia.org/wiki/Spacelab


Space Shuttle Windows

source: framework.latimes.com/2012/09/12/space-shuttle-endeavour/


We Used Two Consecutive Orbits Visible From Plantation, FL

Source: QuikTrack tracking program, AMSAT, Silver Spring, MD


SpectrumAnalyzer

VCR Polarization

switch

Trackingcomputer

Az / Elcontrol

Vertically polarized Yagi

Horizontally polarized Yagi

Source: K. Siwiak & Y. Bahreini, Radiowave Propagation and Antennas for Personal Communications, Third Edition, Norwood, MA: Artech House, 2007

Configuration for TestVertically polarized Yagi









What We Found

• We measured signal strength in two polarizations with:– Astronaut using the Window antenna (rev 61) – Astronaut using D2 Spacelab antenna (rev 62)

• Calculated Antenna Gain• Calculated Faraday Rotation (the rotation of

polarization as a signal passes through the charged ionosphere under influence of Earth’s magnetic field)


200 600 1000 1400 1800 2200-35

-30

-25

-20

-15

-10

-5

05

10

Antenna Range, km

Ant

enna

Gai

n, d

Bi

Window antenna rev 61SpaceLab antenna rev 62

Using the 2nd Longest Antenna Range in the Solar System to Measure Gain

10~11 dB Start of pass

End of passClosest approach


Paths through the Ionosphere

• Electron density known after the flight and tests (so, we can calculate Faraday Rotation)

• Different path lengths result in different amount of Faraday rotation


Ionosphere during rev 61/62 gives us electron density

31022 /10)2(24.1 melectronsfoFNmF


0 100 200 300 400 5000

30

60

90

Time, sec

DegCalculated: about a ¼ turnMeasured: about a ¼ turn

Source: K. Siwiak & Y. Bahreini, Radiowave Propagation and Antennas for Personal Communications, Third Edition, Norwood, MA: Artech House, 2007

0 120 240 360 480 6000

30

60

90

Time, sec

Deg

Bottom Line:

Orbit 61

Orbit 62

CalculatedMeasured

222

)(

20

203

fmc

dzzNBeTurns

e

zmFe


Bottom Line…

• Antenna Range DX was 180 – 1800 miles• The Window VHF antenna was –10 dBi• Faraday rotation is significant!

• Consequence: Today’s ARISS contacts use gain antennas and circular polarization


The Longest Antenna Range?

• SAREX STS-55 was my 2nd Longest Antenna Range Measurement (300 km to 2,200 km)

• My “best DX” antenna gain measurement was on a 720,000 km (447,000 mile) range, and at HF[That’s Part – II: for another day!]


Thanks for your attention!

Kai, KE4PT

[email protected]

Download: www.qsl.net/k4fk/presentations.htm

Documents

Out of this World Antenna Measurements · –Crew phone patches with Family –Special propagation experiments –Ham ATV experiments. 2014 July 9 KE4PT slide 5 STS-80 STS-71 STS-65