Did you know that Fox-1Cliff and Fox-1D will be using different camera image resolutions?
While they both have the same model imager and camera system design, the Virginia Tech students decided that they wanted to try a smaller resolution with their camera because of the need to take two quick successive images in order to get the full 640×480 image. This can cause a “distortion” if the subject of the image is moving, as we saw in Fox-1Cliff EM testing.
Nothing is easy in getting to space and just in case you thought it was, an amateur radio cohort named Murphy will surely remind you that you are in fact working with an AMATEUR RADIO satellite.
Fox-1Cliff, just one day before being taken to Orlando, revealed a problem that would lead to five 16 hour days of hotel room work and a big decision on changes and the course of action needed in order to accomplish delivery and her mission. With environmental testing already proceeding on Fox-1D, Fox-1Cliff had to have the problem diagnosed and investigated and a meeting was then held for a determination of the options for remedy and their risks. The whole process had to be done in record time in order to get Fox-1Cliff into the environmental testing to catch up to Fox-1D for thermal vacuum bakeout to begin on Tuesday, February 9.
If you’ve been here, you know what it’s like. If you haven’t, the picture below gives a little peek into the fun that went on with the three of us seeing very little outside the hotel room other than a few meal breaks.
Burns Fisher W2BFJ and Jerry Buxton N0JY work on Fox-1Cliff late Wednesday night. Photo by Bob Davis, KF4KSS.
Yes, we brought enough checked bags full of equipment to need a minivan for our rental car, but there was still a need for donated equipment from locals Lou McFadin W5DID and Ed Krome K9EK as well as a trip to Walmart!
AO-85 has been formally commissioned and turned over to AMSAT Operations, who are now responsible for the scheduling and modes.
The following guidelines are provided for users:
Uplink power should be on the order of minimum 200 W EIRP for full quieting at lower antenna elevation angles. Your mileage may vary. With an Arrow, 5 W has been used successfully to make contacts.
Polarity is important. The satellite antennas are linear. So, if you are using linearly polarized antennas, you will need to adjust throughout the pass. Full duplex operation facilitates these adjustments while transmitting and is highly recommended.
The downlink is very strong and should be heard well with almost any antenna.
Downlink audio is 5 kHz deviation, as expected. Many will perceive that the audio is “low.” This is an effect of the filtering below 300 Hz, which provides for the DUV telemetry, coupled with any noise on the uplink signal resulting from lack of full quieting or being off frequency. That makes for less fidelity than a typical receiver in terms of audio frequencies passed.
Transmit (downlink) frequency varies with temperature. Due to the wide range of temperatures we are seeing in the eclipse cycle, the transmitter can be anywhere from around 500 Hz low at 10°C to near 2 kHz low at 40°C.
Receive frequency has been generally agreed to be about 435.170 MHz, although the AFC makes that hard to pin down and also helps with the uplinks that are off frequency.
Probably the most notable observations about AO-85 are an apparent lack of sensitivity and difficulty in turning on the repeater with the 67 Hz CTCSS when it is not yet activated, or holding it on by the presence of the CTCSS. We have determined a probable cause for the sensitivity issue and while that can’t be fixed on AO-85 we are taking steps to prevent similar issues on the rest of the Fox-1 CubeSats. The tone detection threshold along with the receive sensitivity issue makes it hard to bring up the repeater. This is being addressed by adjusting the values for a valid tone detection in the other Fox-1 CubeSats now that we have on orbit information about temperatures and power budget. Full details will be in the Nov/Dec AMSAT Journal.
It is important to remember that science is the reason behind the Fox-1 satellites. Not only does science help with the launch cost, it provides a great amount of educational value both from the science payload and in amateur radio itself. The data-under-voice (DUV) telemetry is an excellent way to provide the science without sacrificing the use of the satellite for communications, which would be the case if higher speed downlinks were needed. DUV provides constant science as long as the repeater is in use, which in turn provides more downlink data for the science – a mutually beneficial combination.
Fox-1A is AMSAT-NA’s first CubeSat. Many new techniques are incorporated and lessons will be learned, as with any new “product.” The Fox-1 Project is a series of CubeSats. A total of five will be built and flown. Launches are scheduled for three more, and a new NASA CubeSat Launch Initiative proposal will be submitted for the fifth. We will incorporate changes from what we learn in each launch, to the extent possible, in subsequent Fox-1 CubeSats.
Of the four NASA sponsored CubeSats on the ELaNa XII launch October 8, we are sad to report that ARC1 was never heard from and BisonSat was lost after a few weeks of operation. AMSAT extends our deepest sympathy to the people who worked so hard on these projects. To our members, we want to say that the Fox Team is very proud and pleased that our first CubeSat is very successful and hopefully will be for some time.
A video showing the deployment of Fox-1A from the P-POD aboard the Centaur stage of the NROL-55 launch has been made available.
As each P-POD deployed, the deployment was recorded on video. The video is only about 3 seconds long, so it goes quickly. Jerry Buxton, N0JY, edited the video to add a 1/8 speed “slow motion” of the deployment which immediately follows the original in this YouTube video.
Fox-1A was in the bottom position of the P-POD, with BisonSat in the middle and then ARC1 at the top. You can catch a glimpse of the -Z and -Y faces of the Fox-1A satellite as it quickly disappears into the darkness with BisonSat and ARC1.