[amsat-bb] Monday evening AO-85 passes at WD9EWK...

Patrick STODDARD (WD9EWK/VA7EWK) amsat-bb at wd9ewk.net
Tue Oct 13 06:15:11 UTC 2015


Hi!

No QSOs went in the log on either AO-85 pass I worked this evening, but I
was able to collect 32 data frames on these passes, and unsuccessfully
tried a different HT on these passes (Anytone TERMN-8R). I'll come back
to this radio after I return from Dayton. I used the same two setups on
both passes:

Station 1: AnyTone TERMN-8R 2m/70cm HT, Elk handheld 2m/70cm log periodic

Station 2: SDRplay RSP receiver, 8-inch Windows 10 tablet, HDSDR,
           connected to AMSAT-UK (Winkler) VHF crossed dipole on 8-foot
           mast and tripod

The first pass came by around 0130 UTC. This was a very high pass, up to
almost 72 degrees elevation. Lots of stations on from coast to coast. I
tried to get through with the TERMN-8R/Elk combination. I think I heard
myself early in this pass, but was covered up by a stronger station.
Other than that one instance, I never heard myself through the satellite
on this pass, and didn't hear myself on the HDSDR recording from my other
station. Even though I made no QSOs, I was able to upload 30 data frames
from this pass. Not bad for a portable station with an omnidirectional
antenna on an 8-foot mast and tripod (probably closer to 10 feet/3m high,
including the height of both mast and tripod).

For the later pass around 0311 UTC, I moved my station to my driveway, so
I had a better view to the west and northwest. It was a lower pass, with
maximum elevation of 15 degrees. I didn't hear myself get through on this
pass, but not from a lack of trying. A nice bit of voice activity from
stations along the west coast, and up to VE6WK in Calgary before my LOS.
The SDR receive setup was able to upload 2 data frames from this pass. If
I had my Elk connected to the SDRplay, I am sure I could have pulled a few
more frames from this pass.

The HT I used on this pass is the AnyTone TERMN-8R 2m/70cm FM HT. It was
briefly sold in the US earlier this year, but was pulled from the market.
I bought it earlier this year, used it with SO-50 previously (half-duplex -
lots of desense, like with other Chinese-made dual-band HTs), and have been
waiting for AO-85 to arrive. Its receiver is similar in performance to the
Wouxun KG-UV8D when working this satellite, and not as good as the KG-UV9D.
It is very important to have the best possible signal in the receiver with
this radio, as its performance drops off quickly as the signals weaken. The
TERMN-8R is not as sensitive as most Icom/Kenwood/Yaesu dual-band HTs, and
not as sensitive as the KG-UV9D. I was able to copy the downlink OK, but
due to a variety of issues I only heard part of one transmission early in
the first pass I worked. I will come back to this radio after the AMSAT
Symposium, and hopefully have a better chance to get through on AO-85 at
that time.

I have been asked why I am doing this - using different radios or
combinations of radios to work this satellite. Since we have not had a U/V
FM satellite since SO-35's demise in 2001 (a satellite I worked one time,
in 2000, using two HTs with long duckies), and not counting the ISS U/V
crossband repeater that was on in the mid- to late-2000s (its downlink was
much easier to hear than even AO-85), this is the first time we have been
able to actually test radios against an actual U/V FM satellite.

I attend lots of events around the southwestern USA representing AMSAT,
where I field questions from hams who are either thinking about satellite
operating, and others who may be coming back to this part of our hobby. I
also get e-mails from all over, with questions that I have enjoyed trying
to answer. If I'm able to disprove some incorrect statements that have been
floating around in relation to some of these radios, all the better! It is
better to have more options available for hams to work this satellite, not
fewer. Some of the traditional options for radios that work with SO-50 and
previous V/U FM satellites are not good options for AO-85 and future U/V FM
satellites. Not working SO-50 and other V/U FM satellites full-duplex may
be a viable option for those satellites, but it is a very poor option. Find
a second HT, or even an SDR receiver, if you are trying to set up a station
capable of working satellites - including AO-85 - full-duplex.

I could just use my IC-2820H mobile radio at 50W to log lots of stations on
every possible AO-85 pass I can work. I know this is a great radio for FM
satellites, whether working V/U or U/V. Where's the challenge in doing
that? And there's the SDR stuff that has been fun to use. Having the RF
recordings from HDSDR, which I can use to upload telemetry to AMSAT and
update my logbook, is a powerful tool to help improve my station and my
operating. An SDR receiver with a small tablet is a capable - and less
expensive - way to help build an all-mode satellite station that is capable
of full-duplex operation.

The two RF recordings I made from the AO-85 passes I worked, and other
photos and screengrabs, are now up in my Dropbox space at:

http://dropbox.wd9ewk.net/

(hit F5 until the folder/file listing appears in your browser window, if
it doesn't appear immediately)

My @WD9EWK Twitter feed usually has photos either before or after the AO-85
passes I work, along with other comments and observations I can put into
140-character chunks. This is readable in a browser window without having
to join Twitter, at https://twitter.com/WD9EWK

73!




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


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