amsat oscar 40

8/3/2019 Amsat Oscar 40

1/13

Amsat Oscar 40Amsat Oscar 40World Wide Amateur RadioSatellite Communications

Presented by Stanley Grixti 9H1LOPresented by Stanley Grixti 9H1LO

www.9h1lo.comwww.9h1lo.com


2/13

AOAO--40 was initially known as Phase 3D, or P3D. Its40 was initially known as Phase 3D, or P3D. Its

the fourth amateur Phase 3 satellite, hence the D.the fourth amateur Phase 3 satellite, hence the D.

AOAO--40 is the most complex and feature laden amateur satellite ever flown.40 is the most complex and feature laden amateur satellite ever flown.

Phase 1 amateur satellites were designed to last only a few weeks,Phase 1 amateur satellites were designed to last only a few weeks,having either no or limited means of power replenishment during orbit.having either no or limited means of power replenishment during orbit.

Phase 2 satellites are in a Low Earth Orbit (or LEO), and lendPhase 2 satellites are in a Low Earth Orbit (or LEO), and lend

themselves to communication over distances up to 4,000 miles or so.themselves to communication over distances up to 4,000 miles or so.

Phase 3 satellites are designed to operate over much longer distancesPhase 3 satellites are designed to operate over much longer distancesbecause for most of their highly elliptical orbit they are at a much higherbecause for most of their highly elliptical orbit they are at a much higheraltitude than the LEOs.altitude than the LEOs.


3/13

When launched on November 16 2000, AOWhen launched on November 16 2000, AO--40 seemed to be working correctly, or40 seemed to be working correctly, ornominally, except for the 70cm transmitter.nominally, except for the 70cm transmitter.

Soon after being launched, the satellite started beacon transmission of telemetrySoon after being launched, the satellite started beacon transmission of telemetry

data on the 2m band. And it soundeddata on the 2m band. And it sounded veryvery loud!loud!

AOAO--40 was left in an elliptical orbit, essentially in the same plane as the equator, as40 was left in an elliptical orbit, essentially in the same plane as the equator, as

expected. For optimum use, the preferred orbit needed to be changed somewhat.expected. For optimum use, the preferred orbit needed to be changed somewhat.

On December 13 2000, during some orbital manoeuvres using the 400N motor, AOOn December 13 2000, during some orbital manoeuvres using the 400N motor, AO--40 went silent.40 went silent.

To sighs of relief across the globe, on 25 December 2000 the 2401MHz (S band)To sighs of relief across the globe, on 25 December 2000 the 2401MHz (S band)

beacon was switched on successfully, but a number of systems were now not workingbeacon was switched on successfully, but a number of systems were now not working

correctly, in particular the 2m transmittercorrectly, in particular the 2m transmitter

Despite the setback, on May 5 2000 the transponder (the device allowing twoDespite the setback, on May 5 2000 the transponder (the device allowing two--wayway

communication) was switched on for a trial period until 30 May 2000. With reportscommunication) was switched on for a trial period until 30 May 2000. With reports

from around the globe of worldwide contacts, this proved the satellite to be anfrom around the globe of worldwide contacts, this proved the satellite to be anunmitigated success.unmitigated success.

Some further orbital manoeuvres ensued starting 21 June 2000, this time using theSome further orbital manoeuvres ensued starting 21 June 2000, this time using the

a second motor: the Arcjet (or ATOS). Designed for smaller orbital changes than thea second motor: the Arcjet (or ATOS). Designed for smaller orbital changes than the

400N motor, over a few orbits the Arcjet was programmed to fire for a couple of hours400N motor, over a few orbits the Arcjet was programmed to fire for a couple of hours

at perigee.at perigee.

On 30 June 2000, the Arcjet firings were finished, and AOOn 30 June 2000, the Arcjet firings were finished, and AO--40 was in a slightly better40 was in a slightly betterorbit, but unexpectedly all of the fuel had been consumed.orbit, but unexpectedly all of the fuel had been consumed.


4/13

The equipment is too expensiveThe equipment is too expensive

You need specialist microwave skillsYou need specialist microwave skills

You need expensive specialist tools and test equipmentYou need expensive specialist tools and test equipment


5/13

Receiver setupReceiver setup

Antenna

Downconverter

Receiver


6/13

Receive AntennaReceive Antenna

60cm TVRO Offset Fed Dish

Helix antenna


7/13

Feed does not obscure radiated beamFeed does not obscure radiated beam

Slightly ellipticalSlightly elliptical

Section of a fullSection of a full--size parabolic dishsize parabolic dish


8/13

Convert 2.4GHz to an Intermediate Frequency (IF) Cheap Ex-TV Receive converters can be used

Modifications can be very simple

Simple kits can be built

Ready made converters

9H1LOs Converter G3WDG Kit Converter Drake 2880 Ex-TV Converter


9/13

SSB 435MHz TransmitterSSB 435MHz Transmitter

Between 25wBetween 25w -- 100w RF Output100w RF Output

Linear Amplifier could also be usedLinear Amplifier could also be used

Uplink can also be on 1296MHzUplink can also be on 1296MHz


10/13

435MHz435MHz

>10dBic gain>10dBic gain

8 to 15 Elements8 to 15 Elements

At least 250wAt least 250w ERPERP


11/13

AO-40s Orbit

59,000 65,000 KM at Apogee

1500 850 KM at Perigee


12/13

AO-40s footprint


13/13

Oscar 40 Activity Demo at the MARL

HQ Yard

25th May 2003 starting at 9:30am

amsat oscar 40

Documents