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Re: measuring tape antenna on board satellite




>Stanley,

The 4 original AMSAT Microsats (AO-16, DO-17, WO-18, LO-19) all used 
Stanley brand tape for their antennas because this was quite successful in 
prior OSCAR missions.  For the Microsats Stanley company donated a roll of 
several hundred feet of unpainted material.  To create the antennas the 
material is cleaned, primed and painted with space rated paint (often 
Chemglaze Z306).

This material has the helpful characteristic of being able to fold or roll 
up and release back to its original shape.  When mounting a satellite on a 
launcher it can be bent to fit the available space, held in place with a 
small bracket or cup, and pop loose nicely on separation.

EYESAT (now AO27) used the same material but partially coated with gold.

The UoSats have been using this material for years.

MO-30 and 31 used it as well, including for the 49 Mhz dipole.  That 
antenna was folded up and tied with fishing line.  A nicrome wire was 
wrapped around it and released it when pulsed with a low voltage.  If that 
failed UV would deteriorate the fishing line and release the antennas after 
a few weeks.

Falconsat-1 used piano wire, but I believe three other payloads on that 
launch used tape measure.

Tape measure does produce some shadowing on solar arrays.  If you examine a 
plot of current from the +Z panel of any of the Microsats you can see the 
effect of the change in the width of the shadow as the satellite rotates 
relative to the sun.  Because of this problem, more recently we have used 
piano wire whips.  On a tiny satellite the reduction in shadowing 
translates into a useful increase in power generation.

jw
wd0e@amsat.org
jim@coloradosatellite.com

>G'day,
>
>I am aware that Oscar 3 and ASUSat1 uses measuring tape antenna on board
>the satellite. Are there any other satellites up in the orbit uses
>measuring tape antenna?
>
>cheers,
>Stanley

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