Nu meddelar AMSAT-NA att AO-85 (Fox-1A) är överlämnad från uppstartsfasen till “driftstatus”. I samband med detta presenteras en hel del viktigt information (Källa: ANS 321):
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.
[ANS thanks Jerry NoJY for the above information]