HF Volmet Broadcasts

7/23/2008 – 9:18 pm

While tuning around below the 30m band on my FT-817, I heard a rather loud and clear weather broadcast on 10.051Mhz. It turned out to be a “VOLMET” broadcast from New York. These broadcasts are apparently provided for aviation purposes. Here is a page which lists the various broadcasts:

HF Volmet Broadcasts

I went down to 8.858Mhz to see if I could hear the broadcasts from Honolulu that covered the west coast of the United States. I could!

VOLMET broadcast from Honolulu on 8.858Mhz

Ironically, just before this I was listening to the aviation warnings for Alaska, and heard a volcanic ash warning from the Aleutian volcano, Mount Cleveland. I thought it was cool enough to fire up Google Earth and see where that was. It’s pretty cool actually.

By Mark VandeWettering | Posted in General | Comments (0)

BT878 Audio Capture Trials

7/22/2008 – 11:39 am

I subscribe to a number of different mailing lists related to radio topics. Something that has intrigued me for quite some time is VLF or Very Low Frequency radio, especially so-called Part 15 or “lowfer” operation. There has lately been some overlap with my interest in software defined radio. Some people have recognized that there is a family of fairly inexpensive video capture cards based upon the Brooktree 878 chipset which can be retargeted to do high A/D conversion of raw signals. These cards are quite inexpensive (the last one I got was about $40 or so), so they might make a reasonable platform to create a SDR platform.

Check out BT878 Audio Capture Trials for some information about what is possible.

By Mark VandeWettering | Posted in Amateur Radio | Comments (0)

Happy Birthday, Brainwagon

7/21/2008 – 7:42 am

On this day in 2002, I made my first posting to this blog. If any of you have hung around since then, you will see that it’s gone through a number of twists and turns, just as my own interests have twisted and turned throughout the last six years. I wonder what people have learned about me in the 2,730 posts that I have made here in that time. Sure, you know a bit about what interests me, but my blog isn’t really about my private life so much. Still, I wonder how much of that is revealed from what I type here.

Ever since I added the “on this date” section to the right, each morning I’m reminded of something that I did, or learned, or thought was interesting on the same date in previous years. It’s an oddly comforting and useful thing, to be forced to return to the past for just a few seconds each day, to recall what was going on in one’s head.

Today? I’m worried about my trip to San Antonio to go visit my son who will be finishing up basic training in the Air Force. My car battery seemed to be completely dead yesterday, but after charging seems fine today. Carmen is still looking for a job. Will any of this still be relevent a year from now when this anniversary comes around again?

Probably not.


By Mark VandeWettering | Posted in General | Comments (0)

WWV and WWVH

7/17/2008 – 8:31 am

I have been monitoring 30m to try to detect some of those MEPT (Manned Experimental Propagation Transmitters) that I wrote about a few weeks ago, without any real luck. I’ll be trying again this weekend, but since I was bored, I decided to tune down to 10.000 Mhz and try receiving the time signal. It’s sent with LOTS of power, and so is pretty easy to receive. In fact, I had to enable the attenuator and turn off the preamplifier on my FT-817nd to prevent serious clipping from occurring.

I was confused by something though. I heard both a male and female voice announcing the time: here’s the recording…

Recording of two different time signals on 10Mhz.

And here’s the spectrogram of the resulting signal, just for fun.

Spectrogram of WWV signal…

It turns out that I’m receiving two overlapping signals, one from WWV in Colorado, and one from WWVH which is in Hawaii. Typically, you can only hear one or the other. The WWVH signal is supposedly aimed away from the continental U.S. and you normally can’t hear it, but to keep them from interfering with each other when propagation is enhanced, it announces in a female voice somewhat earlier than the WWV signal does. The two “tones” they use to announce the start of the minute occur at different frequencies too. The WWVH signal also includes marine weather warnings, which you can hear at the beginning.

By tuning down to 5 Mhz, I found that I could no longer pick up the WWVH signal at all, demonstrating that propagation does indeed depend on frequency.

Anyway, super trivial thing, but I thought it was interesting. You can read a lot more about time signals at The NIST Time and Frequency Website.

By Mark VandeWettering | Posted in Amateur Radio | Comments (1)

First Moon Landing 1969

7/16/2008 – 9:09 am

39 years ago today.

YouTube - First Moon Landing 1969

By Mark VandeWettering | Posted in General | Comments (0)

Dear God, Will It Never End?

7/15/2008 – 9:57 pm

The All-Star game is going to the bottom of the 13th in a 3-3 tie. Both teams are 3-27 with runners in scoring position. There have been something like 19 pitchers used. Gadzooks.

Addendum: Uggla just committed his third error, a new player record for the All-Star game.

Addendum: Michael Young gets a sacrifice fly, scoring Morneau from third in the bottom of the 15th. Sweet Zombie Jesus, what a marathon that one was. AL wins 4-3.

By Mark VandeWettering | Posted in Baseball | Comments (0)

Don Mitchell’s Blog

7/13/2008 – 8:38 pm

Today I found out that Don Mitchell has a blog. While I’ve only briefly met Don a couple of times, I’ve been aware of his computer graphics work for quite some time, so it was good to see his writing on other interesting topics. I wish my blogroll had more crazy smart people writing about whatever they are interested and passionate about.

He’s on my daily blogroll now.

Don Mitchell’s Blog

By Mark VandeWettering | Posted in Link of the Day | Comments (0)

Scrappy has the Feline Immunodeficiency Virus

7/11/2008 – 1:23 pm

Well, I suppose I should have seen this as coming. Our adopted feral friend Scrappy has been fighting off a skin infection, and we have had him on antibiotics for the last two weeks, and he went back in for testing, where they test for, among other things, FIV antibodies.

Scrappy tested positive.

It makes me sad. He’s a wonderful cat.

By Mark VandeWettering | Posted in General | Comments (0)

Re: Bandwidth, iTunes, and iPhone activation…

7/11/2008 – 9:02 am

As I’m sitting here with my iPhone, eagerly (and as yet vainly) waiting for it to be reactivated via the iTunes store, I was trying to figure out what the failure mode was that allowed this kind of (by appearances on the iPhone support forum, and news from various bloggers who are in line to buy new 3g iPhone) serious problem to occur.

Here’s the deal: preceding each and every iPhone upgrade, there would appear to be a needed iTunes 7.7 upgrade. This upgrade itself was sizeable (to be honest, didn’t mark down the size). Then, the iPhone 2.0 firmware update had to be downloaded, which was 218Mb additional. These downloads were accomplished without incident. But then you go to activate the phone… and… problems.

Let’s say just consider the firmware update. 218Mbytes let’s say takes… one minute. That’s about what it took for me via comcast. Whatever the rate of new customers getting this update are, they are able to keep up with this load. But they are not able to process the load of (presumably) getting a small amount of information back and forth to your phone to activate it in the same one minute time frame.

In a way, I guess that it isn’t too surprising: after all, web servers which are optimized to serve up static content are very, very fast. Back when I used to run thttpd, it could saturate 10Mb ethernet links running on a 486. But it also suggests that Apple should have realized the assymetry, and throttled downloads to allow their downstream processes to keep pace. It would have avoided a lot of frustration.

Me? My iPhone is still bricked into emergency only mode, and now I’m getting -4 errors from the iTunes store. Patience is a virtue. My phone lives again!

By Mark VandeWettering | Posted in General | Comments (1)

iPhone 2.0 update… in progress! HOLD OFF FOR NOW Well, mine works now.

7/11/2008 – 6:06 am

My cat woke me up before 6:00AM this morning to remind me that today was the Apple 3G iPhone release date. Buying a new phone isn’t in the cards right now, but I suspected that there might be the 2.0 firmware update for my old phone. Sure enough, I powered up the laptop and got a notice that there was a new 7.7 iTunes update. Downloaded it, installed it, plugged in my iphone, check for updates, and…

Nuthin. Still 1.1.4.

Hmmph. Shutdown iTunes, restarted it. Checked for updates.

Eureka! 2.0 currently downloading, 218Mb.

I’ll let you know how it goes.

Addendum: All the cycling of “backup, installing, verifying”, seemed to go reasonably smoothly. Now my phone is in a state where it seems to need to talk to iTunes, and the iTunes needs to talk to the iTunes store, but it’s just not connecting. I’m guessing their servers for unlocking are currently completely swamped because of the 3G release. I’m trying to be patient.

Addendum2: Frown. Now my phone is in the mode where it can apparently make emergency calls, but it is requesting to be connected to iTunes. When I do so, I get this:


Frown!

I suspect this magic error code is just that it’s activation servers are overloaded, but I’m not very happy.

Addendum3: It appears that my surmise was correct. Going to Apple’s support forums:

Forum about bricked iPhones..

Confirms that lots of people are having this magic “-9838″ issue, and that Apple has confirmed that it was for inadequate bandwidth on their end. Sigh. I’m gonna go take a shower.

Addendum4: Word of the day:

iPocalypse

Apparently word is spreading that activations are just horribly slow. My own iPhone has gone from having that -9838 message, to just spinning endlessly, waiting for the iTunes store. As Henry Jones would say, “Our situation has not improved!”

Addendum5: Around noon (after about six hours), my iPhone finally phoned home and I know have a working iPhone again. More later.

By Mark VandeWettering | Posted in General | Comments (1)

Quail!

7/9/2008 – 8:18 pm

My wife noticed a mommy and daddy quail at our fence, with a whole bunch of babies squabbling around in the grass at the bottom. Couldn’t get any good pictures of the babies, but shot this video of the parents:



Not sure the autofocus got the quails as well as they could have, here is the best still picture of them I managed to get, full resolution.

Quail!

By Mark VandeWettering | Posted in My Photos | Comments (0)

Televisor

7/8/2008 – 5:22 pm

Very cool. I want one.



By Mark VandeWettering | Posted in General | Comments (0)

Torpedo Data Computer Mark 3

7/7/2008 – 9:39 am

This came across one of my mailing lists: a complete description of the mechanical computer used to solve torpedo targeting problems during WWII. It’s really very cool, and could serve as a great intoroduction to how mechanical computers work. Very neat.

Torpedo Data Computer Mark 3

By Mark VandeWettering | Posted in General | Comments (0)

Beacon Activity on 30m?

7/5/2008 – 12:58 pm

Well, I decided to try again to record some of the beacons that are on 30m. I recorded 1 hour of what sounds like white noise starting on July 5 around 18:30 UTC, and then ran it through an FFT and mapped out the frequency ranges that represent 10.14000 to 10.140200 Mhz. Here’s a processed version of the spectrogram:

July 5, 2008, 18:30-19:30 UTC

Strictly speaking, only the lower half of the image is within the beacon band, but I haven’t actually calibrated my FT-817, so it might be off a few Hertz. The signals aren’t strong enough for me to identify any of them, but I might actually be getting something.

Here is the naked, unprocessed spectrogram.

Most people who do this kind of listening use Argo, written by I2PHD, and indeed I would except for one thing: no boxes run Microsoft Windows in my house. Well, that and I am kind of interested in the kind of DSP algorithms that enable us to do this kind of stuff. So, I tinker this stuff together for the Mac/Linux.

Addendum: I left the recorder going when I went out today. Around 0:00 UTC, I recorded the following near hour of the band between 10.140 and 10.140100 Hz. Whoohoo! My first real beacon. Not sure who it is yet though.


First real grab of 30m beacon activity!

Addendum2: Hmmm. Figured it out! It’s WB3ANQ I think. His grid in FM19rc is almost 2450 miles away, using a power level of only 200mw!

Hello Knights,

I have joined in on 30 meters 10.140.095 to 10.140.100 Mhz QPS ref.
200 mW with my SNAKE format
/\/\/\/\ 30 second period as of 1900 UTC

--
Larry Putman WB3ANQ
Pasadena, Maryland FM19rc
By Mark VandeWettering | Posted in Amateur Radio | Comments (1)

Backyard Shed Turned Home Office

7/3/2008 – 3:44 pm

Courtesy of Lifehacker, here are some neat pictures of a guy who added an office to his home by using a pre-fab 8×15 shed which was wired, insulated and dry-walled. Very nice. Wonder what the zoning issues surrounding this kind of installation are.

By Mark VandeWettering | Posted in General | Comments (1)