Telecom

Antenna board updates -
Our antenna board prototype has been completed and we have been able to communicate with the ground station with copper wire being used for antenna wire (we have some nitinol wire that we will be using later on). Before APs Kevin Doherty came in to help me trim the antennas to an efficient length. Using his network analyzer, we would cut the antenna down in length in small increments while the network analyzer tested for return loss, which measures how much power sent through the antenna at a certain frequency is being bounced back into the source. We were able to trim our transmit dipole down to a length of about ~35cm from tip to tip with >99% efficiency - less than 1% of the power being sent through the antenna was coming back to the network analyzer. However, when we tried to trim the receive antenna which was supposed to be around ~1m tip to tip, we could not trim the wire down to a length that would make it efficient for our receive frequency of ~435Mhz. We were, however, able to trim it down to an efficient length for our transmit frequency at ~145Mhz. We tried disconnecting extraneous circuitry from the antenna signal traces, thinking there was something in the circuitry that was conflicted with our receive frequency, but that had no effect. It's also possible that the row of vias that the antenna wire runs over was an interference, but the fact that we were able to trim this antenna for our transmit frequency suggests that that's not the problem. Another possibility is that the radio or some component of the basic telecom system of our satellite does not "like" our receive frequency. Mr. Doherty was hypothesizing that the transformer might have been the culprit but consulting its datasheets told us that the transformer should have been able to handle up to 600Mhz.

Subsystem Overview

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Telecom To Do List
Update Link Budget
Power Budget
Uplink/Downlink History
Operating Modes
Be more organized than all the other subsystems
8b on the IARU frequency application form. The form is on the Ground Station page.
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