Hi,
How feasible is it to fly a mode K (15m uplink, 10m downlink) linear transponder on a cubesat?
I expect that retty much any ham with an HF transceiver would be able to work this bird, and I expect that due to the lower frequency, the footprint might be a bit larger than that of VHF/UHF bird in the same orbit and doppler shift would only be about 7% of that experienced on 70cm.
The biggest problem that I see though is squeezing a somewhat efficient 10m antenna into a cubesat and deploying it by remote control once on orbit. (I think that the cubesat antenna should be optimised for TX performance, as cubesat TX EIRP capability is severely limited compared to the average HF transceiver).
Would two 2.5m lengths of steel tape (the same stuff that tape measures are made out of) - mounted on opposing sides of the cubesat, be able to unroll in microgravity to form a generally straight 1/2 wave dipole with a low risk of tangling, snagging or kinking, etc?
Alternately, what about using some sort of thin plastic tubing (something like dialysis tubing, but suited to the space environment?) with a wire inside it, and rolled up. Then, once on orbit, the tubing is inflated with self-expanding polyurethane foam, which will extend the tube (and the wire inside it). The foam will then harden, so future loss of gas pressure in the plastic tube (micrometeorites?) will not cause failure of the antenna?
73 ZL2WRW Ross Whenmouth
Hi,
ZACUBE is a HF beacon. Something like this may be a foundation for what you're suggesting.
http://amsat-uk.org/2012/08/25/14099-khz-cput-cubesat-to-launch-end-of-novem...
It's riding along with FUNcube in the same POD. Take a look at this page, about half way down you'll see the ZACUBE deployment mechanism.
http://amsat-uk.org/2013/09/04/funcube-1-is-in-its-pod/
73
Dave
On 05/09/13 08:09, Ross Whenmouth wrote:
Hi,
How feasible is it to fly a mode K (15m uplink, 10m downlink) linear transponder on a cubesat?
I expect that retty much any ham with an HF transceiver would be able to work this bird, and I expect that due to the lower frequency, the footprint might be a bit larger than that of VHF/UHF bird in the same orbit and doppler shift would only be about 7% of that experienced on 70cm.
The biggest problem that I see though is squeezing a somewhat efficient 10m antenna into a cubesat and deploying it by remote control once on orbit. (I think that the cubesat antenna should be optimised for TX performance, as cubesat TX EIRP capability is severely limited compared to the average HF transceiver).
Would two 2.5m lengths of steel tape (the same stuff that tape measures are made out of) - mounted on opposing sides of the cubesat, be able to unroll in microgravity to form a generally straight 1/2 wave dipole with a low risk of tangling, snagging or kinking, etc?
Alternately, what about using some sort of thin plastic tubing (something like dialysis tubing, but suited to the space environment?) with a wire inside it, and rolled up. Then, once on orbit, the tubing is inflated with self-expanding polyurethane foam, which will extend the tube (and the wire inside it). The foam will then harden, so future loss of gas pressure in the plastic tube (micrometeorites?) will not cause failure of the antenna?
73 ZL2WRW Ross Whenmouth _______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
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David Johnson -
Ross Whenmouth