[amsat-bb] Friday evening - LilacSat-2, AO-85 (yes!!!), and SO-50...

Sat Oct 10 08:34:44 UTC 2015

Hi!

A lot of satellite work tonight, starting with a LilacSat-2 pass, then a
couple of AO-85 passes, and wrapping up with an SO-50 pass approaching
midnight (0700 UTC). Fun stuff, and a lot to scribble about...

The LilacSat-2 pass around 0130 UTC this evening was a nice and high
(almost 49 degrees maximum elevation) pass. One slight problem - the
repeater was off. Regardless of that issue, I listened to the pass
with my SDRplay receiver and Elk log periodic, copying the transmissions
using the HDSDR software on my 8-inch tablet. This also let me prepare
for the AO-85 pass a few minutes later, the first of two AO-85 passes
tonight.

My first AO-85 pass tonight, starting around 0150 UTC, went up the
center of the continental USA. As I expected, there was a lot of activity
on the new satellite. Glenn AA5PK was my first AO-85 QSO this evening,
and I logged 8 more QSOs over the next 10 minutes I was in the footprint.
I was using my Icom IC-2820H 2m/70cm mobile radio for the uplink, at 15
or 50 watts transmitter power (I could not get through with the 5-watt
low power setting during this pass). My SDRplay receiver along with HDSDR
on an 8-inch Windows 10 tablet for the downlink. I made an RF recording of
the pass using the SDRplay at 200 kHz IF bandwidth, hoping I could sneak it
through the Fox telemetry software and upload some data packets after the
pass. The telemetry program appeared to accept my RF recording, even though
it was at 200 kHz and the software was designed to accept 192 kHz RF
recordings from a FUNcube Dongle Pro+. Although the RF recording played in
the program, no data packets were decoded. The SDRplay did a good job
hearing the satellite; I think a little better than the FUNcube Dongle
Pro+. I had to twist my Elk log periodic almost constantly throughout this
pass. It was a nice pass to work, with a maximum elevation out here at 37
degrees.

The later AO-85 pass around 0330 UTC wasn't as high in the western sky, at
a maximum elevation for me at just over 24 degrees. This turned out to be
the first pass I tried one of my Chinese-made HTs, seeing if I could work
this satellite full-duplex. I actually set up two stations in my driveway
for this pass - Wouxun KG-UV9D and Elk log periodic I used to talk through
the satellite; and the FUNcube Dongle Pro+ and AMSAT-UK (Winkler) VHF
crossed dipole, connected to my 8-inch Windows 10 tablet and HDSDR to write
an RF recording of this pass that I could use with the Fox telemetry
software for a data upload after the pass.

Even though the KG-UV9D can tune in 2.5 kHz steps, I stuck with 5 kHz steps
for the uplink tuning. Being able to tune in 2.5 kHz steps did not appear
to help me work AO-85. With the sharper receive filtering in the KG-UV9D, I
set my downlink frequency at 145.9825 for the first minute or so of the
pass, and then moved it down to 145.980 for the next several minutes. Near
the end of the pass, I had to put the HT on 145.9775 MHz to hear the
downlink without the voices sounding off-frequency.

It seemed like I had to twist my Elk more often this pass. I also saw and
heard the fading on my SDR receive setup during the pass. A few minutes
into the pass, I was able to make my only QSO during this pass, a quick QSO
with Tom KA6SIP in northern California. The best part of this QSO, besides
being the first AO-85 QSO I made using a 5-watt HT... I was able to
complete this QSO full-duplex with the KG-UV9D! I could hear in the
receiver when I pushed the PTT, but unlike using this HT on SO-50, there
was no receiver desense as I transmitted to AO-85 on 70cm! This is a very
good sign, and I hope to repeat this using a couple of my other Chinese-
made dual-band HTs on upcoming AO-85 passes (Wouxun KG-UV8D, AnyTone
TERMN-8R). I was not able to get through AO-85 with the HT early or late
in the pass, but near the midpoint when the satellite was around 20 degrees
elevation or higher. I'll see if this is something that will be an issue
going forward, or if the commissioning process will lead to some tweaks on
the AO-85 uplink receiver, to make it a little more sensitive to lower-
power uplink signals.

After this pass, I took my HDSDR RF recording and played it in the Fox
telemetry software on my 8-inch Windows 10 tablet. I successfully copied,
and uploaded, 4 data packets from the 0330 UTC pass! This is one more than
the number of packets I received during two passes last night. Since I
used the FUNcube Dongle Pro+ as my SDR receiver, I knew HDSDR's RF
recordings - at the dongle's maximum input bandwidth of 192 kHz - would
work fine with the Fox telemetry software. Not a bad way to wrap up the
second of the two AO-85 passes - a full-duplex QSO on that HT, and helping
AMSAT with some data uploaded to the telemetry server.

To wrap up the evening, I worked an SO-50 pass from the back yard around
0625 UTC. A very nice late-evening pass, using the KG-UV9D as my uplink
radio and the SDRplay receiver with my 8-inch Windows 10 tablet and HDSDR
as my receiver. Only a few stations on, including Tom WA0POD, Tom KA6SIP,
and Frank K6FW - all who were on the 0330 UTC AO-85 pass a few hours
earlier.

A few observations, in no particular order...

During the 0330 UTC AO-85 pass, there was a 45-second period where the
downlink simply disappeared. Nothing was heard from the satellite. I could
clearly see this on my RF recording with my FUNcube dongle and HDSDR, and
a local friend of mine (Brad KG7NXH) also observed this at his station
in another part of the Phoenix area. When the downlink transmitter came
back on, it appeared that the downlink frequency ramped up to the nominal
145.980 MHz frequency - just like I saw when the voice announcements were
transmitted on the passes Thursday evening. I tweeted screengrabs from my
RF recording in HDSDR the moments when the downlink shut off and then
restarted:

https://twitter.com/WD9EWK/status/652715204287946752

This is also visible in the RF recording I made from this pass. KG7NXH
posted his screengrabs in a thread on the QRZ.com satellite forum:

https://forums.qrz.com/index.php?threads/ao-85.496019/#post-3621413

It seems like my SDRplay receiver is more sensitive than the FUNcube Dongle
Pro+ on these passes. I wish the Fox telemetry software had a little bit of
a "fudge factor" in the WAV files it can process. Since the SDRplay's
smallest bandwidth is 200 kHz, 8 kHz more than the FUNcube dongle's maximum
192 kHz bandwidth, I wonder if there is a way that the Fox telemetry
software could be tweaked to accept WAV files at either 192 or 200 kHz RF
bandwidth. This wouldn't mean the Fox software could directly work with the
SDRplay receiver, but certainly opens up the SDRplay as an option for
working the passes and having a usable RF recording that can be processed
by the Fox telemetry software. Now if I could use the SDRplay and the Fox
software to copy and upload data packets in real time during passes...

Even though the KG-UV9D and probably a few other Chinese-made dual-band
HTs can't work SO-50 full-duplex, they are probably going to be viable
options for a dual-band HT capable of full-duplex operation on AO-85 and
other Fox-1 U/V satellites. For many who have Icom IC-W32As that would
suffer from receiver desense on V/U satellites including SO-50, it is time
to dust them off - these should also be good for full-duplex operation on
the Fox-1 satellites, free of any receiver desense. The time has come to
prove - or, hopefully, disprove - statements about these HTs and their
ability to work Fox-1 satellites full-duplex. :-)

For all of the passes I worked and monitored this evening, I have uploaded
my audio and RF recordings, along with photos and screengrabs, to my
Dropbox space. You can get to those files at:

http://dropbox.wd9ewk.net/

Press F5 if the Dropbox page doesn't immediately appear in your browser
window. This is easier than pasting the long string of gibberish that
makes up a link to a public Dropbox folder. All of my files from this
evening are in folders with name starting with 20151010.

It is approaching the 48-hour mark since the launch of AO-85. Being able to
actually use this satellite, so soon after the launch, is hopefully a sign
that the satellite is in good working order. I know that AMSAT personnel
are still checking over the telemetry being downloaded from the satellite
and uploaded to the AMSAT telemetry server. I hope the 45 seconds of
silence heard this evening was a one-off incident. Add in the LilacSat-2
pass I heard early this evening, to the SO-50 pass just before midnight,
it has been another fun day to work satellites. :-)

Good night, and 73!

Patrick WD9EWK/VA7EWK
http://www.wd9ewk.net/
Twitter: @WD9EWK