All posts by j0n

Ugly or not?

slievenamon.jpg

Which is it? Personally, I think they are fantastic.  The are a lot nicer looking than some of the other structures visible from the same spot, and far more functional.  What really surprised me though was how quiet they are in operation.  The traffic moving along the road from Kilmeaden to Portlaw was easily able to drown out what I think was the noise from them.

Last Monday, Tipperary Amateur Radio Group were on top of Slievanamon (the Mountain pictured behind the wind turbines), participating in the Spring Leg of the Irish Radio Transmitters Society’s 2 Meters Counties Contest.  After some generator trouble, we got going and spend an enjoyable few hours up there (pictures), making approximately 57 unique contacts in 24 counties. It was great to see so much activity on the band.

Last week I was in Innsbruck, Austria, helping Miguel at the Tridentcom conference.  There was lots to take in and lots of folks to meet, too much in fact. I briefly managed to get outside for a look around and take some pictures on Tuesday evening.  The rest of the time was spent either attending technical sessions, or continuing technical discussions afterwards.

Getting set up for the contest was a technical challenge of a different kind (one could consider it therapy almost!).

Geosynchronous Birds.

At the Symposium AMSAT President Rick Hambly, W2GPS, along with Vice President of Engineering Bob McGwier, N4HY, were able to make public the results of their recent work, which will change the face of Amateur Radio going forward. AMSAT has been in consultation with Intelsat regarding an application of Intelsat communications satellites carrying our Amateur Radio satellites into geosynchronous orbit.

Bob described changes in Department of Defense (DoD) policies that will require DoD-subsidized launches to allow secondary payloads to fill in excess launch capacity of the primary mission. During his talk, “Where’s the Launch,” Lee McLamb, KU4OS, explained that factors such as the increased size and efficiency of launch vehicles results in excess lift capacity. Gone are the days where adding a pound to the payload meant removing a pound of fuel from the booster. Lee described how current missions on the schedule have 1000 to 1500 pounds of excess capability. These are slots AMSAT can fit into.

Bob, N4HY, made the following observation about the Phase IV Lite project, “There is enough in place at this time that AMSAT needs to begin planning engineering work and possible construction of a geosynchronous payload so we are ready if Intelsat says they have a ride for us.”

This is a fantastic opportunity for the hobby, read the full article here.

ANDE DEORBIT

Recently Henk PA3GUO and Mike DK3WN sponsored an ANDE award to encourage reception of telemetry during the last few weeks of life of the Amateur Radio satellite ANDE.

ANDE was build by students from the US Naval Academy and deployed from the Space Shuttle (STS-116) on a return mission from the International Space Station (ISS) on 21 December 2006. Due to it’s low orbit it had a short lifetime and re-entered the earth’s atmosphere just over a year later on 25 December 2007.

It operated an APRS AX25 packet digipeater on 145.825 MHz as well as a Voice Synthesizer and other communications experiments.

The ANDE award was awarded to anyone who made QSOs via ANDE or received telemetry during its final 10 days in space.

Along with many others, I had my home station listening for packets from this oversized golfball in order to gather telemetry.  As I was travelling most of the 10 days prior to ANDE’s re-entry, I was unable to make any QSOs through it, but managed to receive enough telemetry to qualify for the award.

PB/PG 2.2.1 Released

From Bent Bagger, OZ6BL:


I’m happy to announce release 2.2.1 of PB/PG for Linux.

PB and PG for Linux are programs used for download from and upload to
digital satellites (Pacsats) supporting the FTL0 protocol. This
software allows you to directly communicate with the Microsat series
of satellites. It provides a Curses (Ncurses) based user interface. It
features automatic directory fill requests and simple, rules based
file download requests.

This release serves two purposes:

1) To show that the project is still alive and kicking

2) To correct a number of small ‘inconveniencec’ and to add a few new
features. These changes/additions are described in the document
‘ReleaseNotes’ q.v. (included in the release)

PB/PG for Linux may be downloaded (in source form only) from one of
these places:

http://www.fern.dk/pgpg/pbpg-2.2.1.tar.gz
http://ibiblio.org/pub/linux/apps/ham/pbpg-2.2.1.tar.gz
ftp://ftp.amsat.org/amsat/software/Linux/pbpg-2.2.1.tar.gz

I may be contacted using this address:  oz6bl (at) amsat (dot) org

Happy hamming

Best 73 de Bent/OZ6BL
 —

I submitted some rather simple patches to the package including IPv6 patches to allow it communicate to a server running predict (which has also been patched for IPv6 support), which were included, then I helped test them with my home station.  Even though I’m only using a vertical antenna, I was able to upload to and download from  the satellite quite successfully on most passes. It’s kinda cool actually, not something one does every day 🙂

DTN and AX.25

Almost 12 months ago Darren, G0HWW sent this post to the linux-hams mailing list. We exchanged some emails discussing how Delay Tolerant Networks (DTNs) could be used for Emergency Communications (being a classic store and forward network). In a DTN network, each sub-net or point-to-point link can operate over whatever stack is available, in this case it is AX25. In August Darren became aware of some work done in Helsinki University of Technology (under Joerg Ott) specifically a paper entitled Opportunistic Email Distribution and Access in Challenged Heterogeneous Environments. Joerg forwarded Darren their DTN Mail Proxy and we started experimenting with it.

Last weekend, we went a step further. Darren sent me on patches to the DTN2 reference implementation that implement an AX25 Convergence Layer. As I had a working 9600 baud AX25 connection we were eager to test it. After some patching, head scratching and recompiling we were able to successfully pass email from my Laptop over AX25 (439.850MHz) to my Linux server, then over the Internet to Darren’s server and on to his mailbox. All using the DTN bundling protocols. Very cool!

TM-D710E and KISS mode.

Happy New Year!

Now Christmas is over, back to business. I spent some time last Saturday testing KISS mode on the TM-D710 to see if Kenwood have improved it. The test scenario was.

Linux Laptop <-> TM-D710E  <-> 439.875MHz <->  SCS-PTCIIex <-> FT-847 <->  Linux Server.

At both sides, the serial ports were running at 57,600bps. I configured both sides to use 9600bps over the RF connection, I used settings of txdelay 100ms, Paclen of 255, maxframe of 7, mtu of 1500, mss of 1460, and tcp window of 2920 as suggested here. Other settings were at their defaults.

I started an FTP download of a (roughly) 1.6MB file from the Linux Laptop to the Linux server, and about 74 minutes later, it completed.  I then downloaded the same file and approximately 70 minutes later it finished.  A quick comparison of the md5 checksums showed the file to be ok.  During the transfers, it seemed to me that the 710 was a bit ‘slow’ in switching from receive to transmit (compared to the PTCIIex which was almost instantaneous).

That said, given my very limited experience with 9600 baud packet, I still think it is respectable, though more testing is needed and I would welcome any suggestions for different parameters to change.

Software Defined Radio

This is very interesting.  Who knows, it may soon be possible to have all the different wireless technologies available on one chipset, all presented as just another ‘ethernet’ device (or maybe many devices.   If  there was an  associated hardware signal to indicate ‘oops.. we’ve had to change networks’ or some other smarts, it would make things very interesting in the whole arena of Terminal/Node Mobility for Internet connected devices

Beavers Eye View.

We departed Whistler this morning after there had been over 2 inches of snow overnight (nuts!).

Whistler Snow

We arrived in Vancouver just in time for lunch. Seeing as it was such a nice day, we wandered down towards the waterfront for a look around, where we came across a Air Charter company. As I had never been in a floatplane, I just could not resist, though I couldn’t persuade Dee to join me. So after some organisation and a quick cup of hot chocolate, Peter (the pilot), another gentlemen and I, headed out to our DHC-2 Beaver (below) for a scenic flight around Vancouver.

The Beaver

The smoothness of the take-off and landing really surprised me (Peter informed me that it had not the smoothest take-off as he had to avoid some debris), though it has been quite a few years since I was in a light aircraft. The landing was the gentlest I think I’ve ever experienced. I guess I have been conditioned by the bumpy landings that are almost normal now in commercial aircraft.

See the obligatory pictures here.

Whistler – Day 2

What a blast! Solely due to the patience and enthusiasm of our instructor Larry, and his ‘shadow’, Alex, our entire group made progress today. I managed to improve my turns to be more HGV like, rather than 747 like, woohoo! Unfortunately our education is now on an indefinite ‘hold’ as we are heading back to Vancouver tomorrow. Just to make it more annoying, it started snowing this evening, so tomorrow will most likely be one of the best skiing days of this week. We’ll just have to come back someday.