There are a lot of details getting settled today before Thanksgiving and then there will be a flurry of activity on Friday in anticipation of Saturday’s launch. I think the theme for today is a series of 3-4 short updates broken up by subject so please bear with us. Some of these updates may be boring to backers who just want to see video and get access to the data; but for us, one of the main ‘deliverables’ of this project is transparency while building and launching the payload for some of our backer friends and family to follow along.
So with that… here’s a diagram of the cross-band repeater payload that will be flown.
The ‘flow’ through the repeater starts in the top left corner with the uplink antenna (RX). Radio signals are received by the antenna on a certain frequency by the uplink radio and instead of being heard through the speaker, are sent to the headphone jack that a user would wear (there are actually two paths out of the radio but I’m keeping it simple). The audio passes through a purchased device that I’m calling the Flux Capacitor because I am the non-HAM of the group yet I’m writing this update; basically it detects that there is an audio signal from the left radio and keys open the radio on the right and says ‘transmit this’ because there isn’t a person up there to hit the push-to-talk button. The radio on the right transmits the voice down a completely different frequency on a different frequency band.
One of the genius things about this setup (to me) is the device that you see at the top on the image. It is an Arduino that is programmed to inject Morse code tones into the downlink radio at <10 minute increments. Amateur radio rules require an unmanned repeater to identify itself at least every 10 minutes but because this isn’t a ground-based station we had to get creative. We had a few choices and one was to record a .wav file of the station ID tones and broadcast the .wav file audio OR program the arduino to send a certain frequency tone at Morse-code dot/dash intervals. We settled on this Morse-injector and set the rate to some value less than 10 minutes.
Also, due to weight restrictions, we opted to take this equipment out of it’s own separate payload container and we have shifted these radios into ‘my’ camera payload. I had plenty of volume, the radios generate heat which will help my batteries, and we save weight because we don’t have another container/structure to loft underneath.