Earthquake… again…

Yep. Another earthquake. I had just gotten of the phone with Carmen when I felt the slow, periodic roll of an earthquake. The shaking was relatively slow but fairly large in magnitude, and persisted for nearly ten seconds. The cat was not particularly happy with the shaking either, and he meowed to be let out (but then immediately came back for more food). Apparently the quake was of quite reasonable size: a 5.6 in the South Bay.

Earthquake 10/30/2007

I usually shrug these things off, but this was actually big enough to be noticeable and a little disturbing. Hope all of you out there are fine.

First QSOs via AO-51

Well, I’m not much for operating really, but I have been trying to work up the courage actually talk on the AO-51 amateur satellite.  It was down from October 18th, but today was back up and running the repeater.  I am still using a handheld Arrow crossed Yagi, so my hands are pretty busy, but I’m slowly calming down enough to keep the satellite in the pattern of the antenna, and tonight, I decided to try my luck on the westward pass of AO-51.  The westward passes are a little calmer than the eastern passes.

Of course, all was not perfect.  For some reason, I was picking up a huge amount of interference from the little VN-120 recorder that I used so successfully last time.  Nevertheless, I set it up, and aimed the antenna to the south where I expected the satellite to show up.   Soon, there was some traffic, and I heard NH7WN, who is in Honolulu.    I haven’t double checked this, but I am pretty sure that Honolulu is just at the limits of what we can hit from the San Francisco Bay area.  (A quick calculation shows that the distance is about 2400 miles).  Pretty damned good.

Here is the MP3 early in the pass: NH7WN via AO-51

I then was getting some horrible screeching interference from the little recorder.  Not sure what was going on there, but I didn’t like it, so I switched the recorder off.  Sadly, that means I have no record of my first QSO via AO-51.  I’ll get that worked out soon.  My adrenaline was pumping, and I called out a callsign.   For the life of me, I don’t remember which one it was.   K7WJS?  Not sure.  How pathetic is that?  I’m afflicted by an inability to remember people’s names unless I write them down, and when your hands are full of an HT and an antenna, it’s impossible to write them down.    The second call was K6YK, John in Stockton, which is much closer than Honolulu, but still fun.

Just after that, I started to lose the satellite.  There are hills to the north behind me, and the tree cover isn’t ideal either, so I called it a night.    I’m gonna have to work on getting a better setup for this.  The things I think would help are:

  1. a tripod for the antenna and HT ala K7AGE
  2. a light, for these outdoor passes
  3. a clock that reads in both local time and UTC
  4. a recording solution that doesn’t put hash on the line
  5. less caffeine, to calm me down during the pass.

Anyway, I’m gonna send off some emails and call it a night.

Technorati Tags: , ,

AO-51 appears to live!

I was going to present a link the cool OSCAR Satellite Status page by KD5QGR because it can be useful for beginners to see which satellites other amateurs are hearing. If you’ll notice, for a long time only telemetry was being heard on AO-51 (the easiest of the LEO satellites), but in the last few hours it appears that people are making real contacts on it. Woohoo! I’ll have to try this out when I get home tonight. I probably won’t try to make a qso, but if I get some audio, I’ll post it here.

Technorati Tags:

How I track satellites…

I was chatting with my brother about my recent attempts at satellite tracking, and he expressed the opinion that it would be nice to present some of the details about how I actually figure out where satellites are. I’m not sure that my methodology is particularly noteworthy, but here’s what I use:

There are lots of great programs for Windows to do satellite tracking (I’ll try to dig up some links for some and post them later), but I am sworn never to use Microsoft operating systems again, so I needed a different solution. I use a fairly low tech solution, namely the predict software by John A. Magliacane, KD2BD. It’s a open source program that was developed under Linux and released under the GPL. It’s pretty straightforward, so it shouldn’t be hard to port it to any unix-like operating system. There are even fancy front ends which create fancy X11 displays. Me, I mostly use the classic curses version. It’s quick, and I can run it on any of the machines I’m likely to have handy, or can ssh to in a pinch.

All these programs require a set of orbital elements, which are basically a set of numbers that define the orbits of satellites. These numbers are available from a number of sources: I fetch them automatically using a simple cron job on my unix box so they are always up to date. For instance www.celestrak.com/NORAD/elements/amateur.txt always contains the most recent orbital elements for amateur satellites. Similarly, there are links for visually observable satellites, weather satellites, and the Space Shuttle (if up) and the ISS. The format of these files is pretty simple: each satellite is defined by three lines, the first containting the name, and the second and third containing a bunch of numbers that define the orbit. To make predict use these, create a file called predict.tle in your ~/.predict directory that contains up to 24 of these satellites. That’s pretty much it. When you run predict for the first time, it will ask you where on the earth you are (lat, long, and altititude), and then present you with a menu that allows you to do a bunch of interesting stuff, like predict passes for a particular satellite, show details of a single satellite, or the current position of all the satellites. It’s pretty simple really.

For instance: here is the multi satellite tracking display that I get. Most of the satellites are amateur satellites that are worth tracking.

Predict Multi Satellite

If you look carefully, you’ll see that AO-58 is currently up (it has a positive elevation). If you shift to the single satellite display, you can get more detailed information, that looks like this:

Predict AO-58

Of particular use to the radio amateur are things like the RX frequency, youll see it is a bit above the nominal downlink frequency. Because it is approaching, the beacon is Doppler shifted up in frequency, and you have to tune high to hear it. You can also see that the distance to the satellite is about 676 miles, and that the path loss to the satellite is about 146db.

This is all useful for interactive use, but you can also get some details about a pass of a satellite using the “P” or predict command. For instance, today’s tracking of the packet satellite NO-44 gives the following:
Prediction of NO-44

The next pass begins at 18:UTC, and begins at azimuth 239 (south west). It reaches a maximum elevation of 25 degreees about 7 minutes later, at around azimuth 300, and then we get loss of signal at 18:53, almost due north at azimuth zero.

This program has a number of additional capabilities, such as being able to predict the position of the sun, the moon, and visible passes of satellites. If you are looking for something more glorious, you can try installing the gpredict package on your Linux box:

gpredict

If you are using Windows, there are some great options, the one that seems the nicest that I’ve seen recommended is Orbitron, which has the added advantage of being free (the author just wants you to send him a postcard). Try it out.

Technorati Tags: ,

Buried in an AO-27 Pileup

Olympus VN-120Well, I’m trying, but I’m finding that I need a third hand to work satellite handheld. Maybe some kind of tripod ala K7AGE would free up my hands enough to be able to be a little more calm. I managed to get my call out, but I failed to copy the responder’s call properly, so this doesn’t count as my first satellite QSO. I’ll probably try again in 90 minutes on the last pass of the day.

The calls I think I copied were KI6IUJ, Laguna Beach, WD8PFS, DM12, KE5GFS and KC9ELU, EM79. There were other calls, and maybe I got these wrong, but that’s what I heard.
Maybe I’ll try to record the next pass.

Addendum: In retrospect, I’m pretty sure it had to be KI6IUJ who responded to me. He responded with only his gridsquare, which I copied as DM13, and he’s the only one in that gridsquare that I’ve got on my list. I’ll send him an email.

Addendum2: Second pass was no better. Got flustered again, and really only tried when the bird was already past me. I recorded the pass using a little voice recorder, here is the mp3 and the much bigger wav file. The dead air in the middle is when I first tried to key down, but of course I was actually set in the DOWNLINK frequency, so it was worse than useless. The second time toward the end it’s far from clear anyone is hearing me, but the sound you hear is me coming back from the satellite. Oh well. I’ll have to rig a tripod up to make this a little more reasonable.

Addendum3: The hams that are in the recording are KG6WHO (DM04) and the aforementioned KI6IUJ. I’m recording these because I suspect I’ll hear these hams again and again, and if I have some idea who is calling, I should be able to dive in with less mental effort.

Addendum4: The recording above was done with a little $25 voice recorder that I had lying around. It’s actually not bad, considering. It will record about 45 minutes, and runs on a pair of AAA batteries. To record, I put a mono 2.5mm to 3.5mm headphone adapter into the speaker outlet, then used a headphone splitter, sending half to a pair of ear buds, and the other half to this recorder. I then played this back into my laptop, edited it with Audacity, cutting out the large amount of static crap at the beginning, and then saved it out as a new .wav file, and compressed that to an mp3 using “lame”.

Programming the Kenwood TH-D7A

Modern ham transceivers are complex. Really complex. They have dozens and dozens of settings, hundreds of memories, and they are kind of a pain to program. That’s why most radio manufacturers now include an ability to “clone” a radio from another one, and perhaps even a way to actually use software to design a configuration and load it into the radio.

Of course, the protocol they use is hard to find, and is likely something the manufacturer doesn’t want to talk about. But if you dig around, you can probably find it.

Here’s the command list for the TH-D7a.

I’ll probably set up a cable for this thing this weekend, and then write up a simple Python program using this information. I’d like to convert my local list of repeaters into a good configuration, as well as include reasonable setups for the major satellites.

Technorati Tags: , ,

First Successful Satellite Communication!

TH-D7AHey, a milestone for me. During my morning commute, I managed to actually send a position report to the amateur radio satellite GO-32, which got picked up by W7KKE in Lincoln City, Oregon, a distance of 810 miles, not bad! I wasn’t sure it had worked, but I noticed that I had received some packets from W7KKE, so I thought I’d do a web search and potentially send him a message and ask him some questions about APRS, but I found this website in finland which archives APRS gateway information by callsign. Sure enough, as I glance down the page, I noticed that he actually reported that he had heard me! Indeed, the gateway created a record for me as a bonus. Nifty!

All of this is probably jibberish to a lot of you. If you don’t already know what APRS is or what GO-32 is, you probably are completely lost. Never fear: I’m having so much fun with this stuff, I am going to try to make a couple of introductory pages on how this stuff all works and what it’s all about over the next few days. Stay tuned.

Addendum: The record I sent indicated that I was using a TH-D7A and an Arrow antenna. While I was using the TH-D7A (pictured at the right), I was just using a little magmount omnidirectional antenna on the roof of my car. The radio puts out about 5 watts. It’s pretty impressive that this works at all.


Addendum2: Map showing my APRS positionIf you click the tiny map on the right, you can see a screen dump of my position on a Google Map.


Technorati Tags: , , , ,

More Satellite Stuff…

Well, I haven’t had a lot of time to do anything good this weekend. I spent some time mowing my lawn, pulling weeds, fertilizing, and examining my fence for needed repairs. But I did spend some time to actually figure out what my problem was with receiving signals from the AO-27 amateur satellite. It wasn’t really clear to me, but the AO-27 satellite is only activated for south to north passes beginning at 30 degrees north latitude. What this means is that there are passes where AO-27 isn’t activated as it passes over head, as well as times when it might be activated late or deactivated relatively early in a pass. Today, I tracked one pass very well through acquisition all the way to LOS, and had another pass where I was a bit behind, so missed the early part of the pass. Interesting. I’ve also been practicing the juggling that I need to do to control the HT while doing all the rest of the stuff. I’ll get there eventually.

I didn’t hear the AO-51 satellite on its pass either: I guess it is still down. Stations are beginning to report that the telemetry on the downlink is hearable, but when I tuned to 435.150, I didn’t hear anything. It was only later that I realized that the downlink is via 9600 baud packet, which can sound astoundingly like static. I’ll have to set up the squelch control next time to see if there is actually a signal strong eough to break the squelch, then I’ll know if it is actually up.

I didn’t have a chance to hear SO-50 today either.

Oh well, for some fun reading, try N1ASA’s excellent PDF on working the FM satellites with portable equipment and he even has a recording of himself working 7 stations on AO-51. Good stuff.

Addendum: From the AMSAT news page:

Drew, KO4MA AMSAT-NA Vice President of Operations reported that at 1848Z on OCtober 11 the software on AO-51 crashed and shut down both transmitters. The repeater and BBS have been down for several days while the command stations reload and restart the software.

On October 17, Drew reported on progress by the AO-51 Operations Team, “We are making good progress in reloading the software necessary to run AO-51, although it was a bit of a rocky start. The control stations hope to have AO-51 reloaded by the weekend of October 20-21. As we reload and restart operations on the satellite we will be able to better predict its return to service.”

Interested stations can use their TlmEcho software to watch progress on the 435.150 MHz downlink. This downlink may only be on over the Southeastern US depending on how far along the reloading has proceeded.

Pacificon

I spent yesterday wandering around Pacificon. Nothing too exciting to report: I picked up a book or two, no major purchases. The QRP related activities were a lot of fun, and I managed to win a bid for a BLT tuner kit from qrpkits.com . Oh, and I decided to try to upgrade my Technicians license. A month ago, I had read most of the General class license pool, and was taking online tests, and scoring in the 80s or so. Last night, I reread about 60% of the question pool. I ended up missing only a single question. It was free to try to take the Extra exam too, so I gave that a try. Sadly, I didn’t do as well (missed a passing grade by three questions). Still, upgraded to a General, hooray for me!

I’m gonna head out to the swap today (for which I am certainly too late to get any bargains) and hang out for a little bit.

Technorati Tags:

The photon/XOR system

It’s 8:22AM, and I’m just waking up, checking my email and surveying my usual blogs with Google Reader. I don’t have time to explain why this link seems interesting, but if you are interested in random walks, computability or cellular automata, check out the following link. I haven’t had time to absorb it yet (and probably won’t until tonight, given that I should be on the road shortly) but it seems very interesting.

To me, anyway.

The photon/XOR system

Hey, I can hear AO-51 from my car…

I noticed that a 56 degree elevation pass of the amateur satellite AO-51 was going to occur just after 9:00am this morning, while I was commuting. I normally carry my little VX-3R with tiny mag-mounted dual band antenna on the roof. This is the same gadget that I used to receive the AO-51 broadcast of the Sputnik anniversary message a couple of days ago. During that pass, they claimed that they had boosted the power output, so I had no problem getting full quieting using my longer J-Pole antenna, but I was unsure how good this little gadget would do at the normal FM repeater power levels and the smaller antenna.

Well, it seems like I can still receive it pretty well. I didn’t have the doppler shift programmed in (I had just set it to the middle frequency of 435.3 MHz) so I was just listening with the squelch off. Sure enough, lots of white noise, which began to shift in frequency, then quiet, then voices! I couldn’t take notes for the callsigns, but there were people operating from gridsquares DM03 and DM33 which correspond to someplace in southern California and Arizona respectively. Pretty neat! Sometime soon, I’ll have to get my laptop set up to record the audio, and I’ll place it here.

Just a bit of Monday morning fun.

Technorati Tags: ,

Addendum: The first of two evening passes sounds like this. Okay, the mp3 is pretty bad, you could try the wav file if you want to wait a lot longer. At the beginning, N5ZNL identifies his position as grid square EL19, which is in Texas. I’m in DM87, just outside of San Francisco. I need a calculator to figure out what the distance is.

Addendum2: The second of today’s passes as an mp3 or alternatively as a much larger WAV file. The audio starts a couple of minutes in. I did a bit better job tracking the Doppler on this one.

FCC-1 Assembled

FCC-1 Frequency CounterLast week I got my FCC-1 kit from the Norcal QRP club. It’s a nifty little PIC based frequency counter, and is quite inexpensive. It’s not very hard to assemble, but I still managed to have a couple of minor problems. Hint to anyone assembling the kit: REMEMBER! The switches are soldered on the wrong (component) side of the board. I thoughtlessly soldered the first one on the wrong side, and had to dig out my desoldering tool and resolder it. When I first powered it up, I didn’t get a proper display. But a quick inspection of some of the soldered joints for the digital display revealed a couple of pins that looked a bit spotty. A quick touch up with the iron, and voila:

I haven’t gotten it hooked to a radio yet, but I will eventually get it hooked to my TenTec 1056 receiver that I’ve been ranting on about for the last week or so. I also need to find a good case to mount it in (I don’t think there is a good place to mount it in the TenTec case, and besides, I might want to move this counter around as I complete other projects.

Technorati Tags: ,

FCC-1 Hooked to the TenTec 1056Addendum: I couldn’t resist actually wiring it into my TenTec 1056 receiver, even though I didn’t have the proper coax or connectors. The good news, it appears to work! Woohoo!