Sunday, August 11, 2013

Mystery Royal Air Force VOLMET Broadcast on 11159khz

In the last couple days a RAF VOLMET (aviation weather advisory) broadcast has been heard with a very strong signal here in the US on 11159khz. The RAF did not change frequencies because the European signal is still on its usual frequency of 11235khz.

After a good bit of analysing of the signal by myself and others in the shortwave listening community, it appears as the signal is originating from somewhere in the Western part of the US. Another curiosity is that the broadcast is the same as the normal VOLMET broadcast on 11235khz but slightly out of sync with it.

As of this morning, 11 August 2013 @ 1602z, I am not receiving it at my station and there have been no reports from anyone else that it is still on the air. I will update if it is still broadcasting. [EDIT: Just received a report that it is still broadcasting.]

This whole thing is very odd. It's mysteries like this that make shortwave listening so interesting. Here is a clip of the audio I recorded of the mystery VOLMET broadcast.

Sunday, May 26, 2013

Alvira, Pennsylvania and The Bunkers

A while back my friend Jared and I visited Pennsylvania State Game Lands 252 near Allenwood, Pennsylvania which is where the town of Alvira once existed. In the spring of 1942 the federal government seized the town and evicted the residents. They then bulldozed the town and built an explosives factory with many igloo shaped storage bunkers throughout the area. When the government found that the need for explosives wasn't as great as what was initially thought the explosives factory was closed down. The residents were promised to be reimbursed at the market rates of the time for their land and homes and they were told they could return to their homes after the war was over. This turned out to be a falsehood and really is a terrible injustice. If the federal government was capable of this kind of abuse in 1942, just imagine what it is capable of now.

Here is a PA Game Commission map of the area. The small circles represent the location of a bunker. 142 of these bunkers were built.
A Google Earth satellite image of the area.

Jared standing at the door of bunker number one.

Some exposed rebar.

I got curious as to why some of the door vents were severely corroded and others were perfectly intact so I stuck my camera inside and took some pictures with the flash.

This is what we discovered. The Game Commission must be using some of the bunkers to store hazardous materials.

A tick that decided to hitch a ride on my pant leg. Rather it chose there rather than boring into my skin I suppose.
Jared peering down one of the top vents of a bunker. If the explosives contained inside were to accidentally ignite, the bunkers were designed so the blast would vent through the top of the bunker through these roof vents.

A look down through the vent to the center of the bunker.

There is a lot of poor quality graffiti on and in the bunkers near the access road. The access road is also called Alvira Rd.

The entrance door to one of the open bunkers.

Jared standing inside the door.

The inside of a bunker. Lots of graffiti as you can see.

The ceiling vent.

The acoustics inside these bunkers is something that cannot be described with words. Here is Jared whistling "Somewhere Over the Rainbow." The sound is beyond eerie.

I hope you have enjoyed this little photo essay. Here is a Google Maps link to the location of the area. If you visit it, please be respectful. It is a very pretty and very cool place to explore so lets keep it that way.

Tuesday, May 21, 2013

Vostok Watches: The AK47 in the World of Timepieces

I have always had a bit of a passion for wrist watches and really any kind of time keeping devices you can think of. Recently, I purchased my second Vostok dive watch and I feel that these watches are worth a mention here because, in my opinion, they are the best deal on a quality mechanical wrist watch out there.

Vostok watches are all "mechanical" watches. The term "mechanical" means that all the workings of the watch's movement are purely mechanical using nothing more than springs, wheels, tiny gears, etc. There are no electronics in the watch whatsoever. These types are either simply wind up watches which need to be hand wound every day or they are "automatic" meaning that there is a mechanism that uses your body's movements to automatically wind the watch. All Vostoks are of the automatic variety.

Vostok is a Russian watch maker located in Chistopol, Tatarstan, Russia. In 1965 they became the official watchmaker for the defence department of The Soviet Union. Also in this year they created the Komandirskie or "commander's" watch. From experience gained from manufacturing the Komandirskie watch they then developed the Amphibia series of dive watches. During the Cold War these were highly sought after timepieces for military personnel. Which watches you could buy was dependant on what your position was in the Soviet military. Special paperwork was needed to purchase them from stores which catered to the Soviet military.

Vostok watches were even worn into space. 
This is a picture of cosmonaut Yuri Romanenko wearing a Vostok timepiece.

The Cold War has been over since 1991 but the Vostok factory has still been manufacturing these rugged and unique watches to the current day. In fact, many folks and myself included consider these the AK-47 of the watch world. They're inexpensive to manufacture, rugged, and extremely reliable. In the event of nuclear attack, they were designed to be impervious to EMP which stands for Electromagnetic Pulse which is a burst of energy that is released from a nuclear blast that will damage electronics and other hardware.

The key distinction between the Komanderskie and Amphibia lines is the Komanderskie watches are not designed to be submerged in water but can withstand an accidental dunking and the Amphibia watches are designed to be taken into the water. I'm not going to get into the details of the various movements used for the different designs in the Komandirskie and Amphibia lines but most are either 17 jewel or 31 jewel movements. Some have the date on the face and some do not. They all use artificially manufactured rubies which act as highly durable bearings for the moving parts so the watches maintain their accuracy over time.

Both watch lines have organic crystals that, if scratched, can be easily buffed out with metal polish or even tooth paste. In the case of the Amphibia series of watches, the water pressure created by depth actually pushes the crystal tighter into the seal which renders it more water resistant the deeper you go. There is a YouTube video where a gentleman tested his to 17 bar pressure which is equivalent to 170 meters which can be viewed here. Most Amphibias are rated to 200 meters depth.

There is a plethora of different face and case designs out there in both lines of watches so there is sure to be something to suit just about anyone. At the time of this writing, the only place to buy these watches is on eBay, at least that I know of. That is where I purchased both of the Amphibias I own. If anyone knows of an online retailer that sells them, please let me know and I will modify this post.

I hope you enjoyed this post and found it informative. I really love these watches and I feel they are a tremendous bargain. Beware though, they can become addicting!

Friday, February 8, 2013

RTL-SDR a VHF-UHF Software Defined Radio for $17 - A Primer

I have known about these RTL-SDR dongles for a while now and I finally got my hands on one. They were originally designed to be TV receivers but are capable of being used as VHF and UHF software defined radio receivers when used with the proper software. They are also capable of operating on FM, AM, and SSB modes. Any radio enthusiast will tell you that these are very powerful devices for a mere $17.

The model I purchased from eBay is the TerraTec T-Stick with the European PAL style coax connector:

Once you have the hardware, the next step is installing SDR software. I am running the Ubuntu 12.04 operating system so I installed GNU Radio. Instructions can be found here. and then the Gqrx tuner software which can be found here. The README file has instructions on how to install the software.

A good tuner software for Windows is SDR#.

The Gqrx interface is somewhat straightforward. You are greeted with a spectrum analyser display with a waterfall. It has all the basic rig control functions such as squelch, RF gain, mode control (AM/FM/SSB), etc. With 15 minutes or so of experimentation, one can get very familiar with how things work.

The last item to address is the antenna. You might as well throw away the antenna it came with. The only thing it will be useful for is picking up FM broadcast stations and pointing at things. A good antenna to start with is an off-center fed dipole. Here is a link with instructions on how to build one on the cheap.

I would recommend building the wire version. These dongles were designed for TV reception. TV cable and connectors are all 75 Ohm. This design starts with a 300 to 75 Ohm TV matching transformer as the feed point for the antenna so it's no issue using 75 Ohm TV connectors and cable for your needs.

Here are the Radio Shaft parts you'll need:
-- 300 to 75 ohm matching transformer:
-- Female 75 Ohm coax coupler:
-- Male European PAL Adapter:

Also, you will need a length of 75 Ohm coax to fit your needs. If you can find these parts at a hardware store such as Lowe's or Home Depot, you will probably save a few dollars. I don't know for sure if a hardware store would have everything you need, however.

Where you go from here is up to you. There is a never ending list of interesting things to hear out in the æther such as the International Space Station, aircraft, amateur radio operators, and emergency service responders. This will get you started in the adventures of radio receiving with a very powerful set up right off the bat!