Retrotechtacular: A Tour Of WLW, A 500,000 Watt Radio Transmitter

July 26, 2013 by Mike Szczys 61 Comments

retrotechtacular-wlw-transmitter-tour

This is an overview of a 500,000 Watt radio transmitter site. It’s one of the slides shared in a guided video tour of the transmitter’s hardware. The radio station — whose call sign was WLW — called itself the Nation’s Station because of its ability to reach so much of the country.

It operated at the 500 kW level starting back in the 1930’s. The technology at the time meant that there were a lot of challenges involved with transmitting at this level of power. It took 750 kW input to achieve the 500 kW output. To reach that the station had a set of AC motors in the basement generating the 4500 Amps at 33 Volts DC ~~needed to power the transmitter~~ to heat each filament. Obviously there was a lot of heat generated at the same time. The system was water-cooled. An elaborate network of Pyrex pipes carried distilled water to and from the tubes to handle the heat dissipation.

The video tour lasts about thirty minutes. It’s just packed with interesting tidbits from the experts leading the tour so add it to your watch list for some geeky entertainment over the weekend.

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Packing A Jeep Wrangler Full Of Hacks

July 5, 2013 by Mike Szczys 66 Comments

Picking just one image to show off all of the hacks done on this Jeep Wrangler is a tough order. We decided to go with this custom ceiling console as it features the most work done in a confined area.

Give the video walk-around a bit of time before you decide it’s not for you. [Eddie Zarick] spends the first moments touting his “Oakley” branding of the vehicle in decals, emblems, embroidered seats, zipper pulls, and more. But after that you’ll get a look at the pressurized water system we previously saw. Pull open the back gate and there’s a nice cargo cover he built that includes a cubby hole which stores the soft sides when he wants to take the top off. There are several other interesting touches, like the police radar spoofer that he uses to scare the crap out of speeders. Ha!

The ceiling console we mentioned earlier was completely custom-built. It includes a CB, scanner, HAM, and seven-inch Android tablet. There is also a set of push buttons which control the various bells and whistles; well, spotlights and inverter actually. Just add a commode and he’s ready to live out of his car.

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Reverse Engineering A Wireless Protocol

July 1, 2013 by Brian Benchoff 31 Comments

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Like all good tinkerers, [Andrew] decided to figure out how his wireless security system worked. Yes, it’s an exercise in reverse engineering, and one of the best we’ve seen to date.

After breaking out the handheld spectrum analyzer and TV tuner SDR, [Andrew] cracked open a few devices and had a gander at the circuit boards. The keypad, PIR sensor, and base station all used a TI radio chip – the CC11xx series – that uses SPI to communicate with a microcontroller.

Attaching a logic analyzer directly to the radio chip and reading the bits directly, [Andrew] started getting some very good, if hard to understand data. From the security system specs, he knew it used a ’20-bit code’, but the packets he was reading off the SPI bus were 48 bits long. The part of this code was probably the system’s address, but how exactly does the system read its sensors?

The easiest way to figure this out was to toggle a few of the sensors and look at the data being transmitted. With a good bit of reasoning, [Andrew] figured out how the alarm system’s code worked. This theory was tested by connecting one of the radios up to an Arduino and having his suspicions confirmed.

While [Andrew]’s adventure in reverse engineering is only a benefit for people with this model of security system, it’s a wonderful insight into how to tear things apart and understand them.

Wireless Microcontroller/PC Interface For $3

May 19, 2013 by Brian Benchoff 48 Comments

Sending data from a microcontroller to a PC usually requires some sort of serial connection, either through fiddly on-chip USB, FTDI chips, or expensive radio ICs. [Scott] didn’t want to deal with this when creating a network of wireless temperature sensors, so he hacked up a few cheap 433 MHz radio transmitters and receivers to transmit data to a PC for about $3.

After sensor data is collected on a microcontroller and sent over radio, there’s still the issue of getting it into a PC. For this, [Scott] piped the data into the microphone port of a cheap USB sound card. We’ve seen this trick before both in the world of microcontrollers and loading programs onto a Commodore 64 via a cassette interface.

Once the data is sent into the sound card, it’s decoded with a a small Python app. Given the range and quality of the RF transmitters and receivers [Scott] says it’s not an extremely reliable way to send data to a PC. It is cheap, though, and if you need to read sensors wirelessly on a budget, it’s hard to do much better.

Check out [Scott]’s demo of his creation below.

[youtube=http://www.youtube.com/watch?v=GJHFldPwZvM&w=580]

AM Tube Radio Restored And Given MP3 Playback Too

May 2, 2013 by Mike Szczys 46 Comments

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This AM radio looks a bit like it did coming out of the factory. But there are a lot of changes under the hood and that faceplate is a completely new addition. The project really is a restoration with some augmentation and [Michael Ross] did a great job of documenting the project.

The Kenyon radio was built in 1946 and uses vacuum tubes for the amplifier. Considering its age this was in relatively good shape and the first thing that [Michael] set out to do was to get the electronics working again. It involved replacing the messy collection of capacitors inside. He then cleaned up the tubes, checking for any problems, and put the electronics back together to find they work great!

He cleaned up the chassis and gave it a new coat of finish. The original dial plate was missing so he built a wood frame to match a dial scale he ordered. The bell-shaped brass cover hides the light that illuminates the dial.

He could have stopped there but how much do people really listen to AM radio these days? To make sure he would actually use the thing he added an Arduino with an MP3 shield. It patches into the antenna port via a relay, injecting modern tunes into the old amplifier circuit. Catch a glimpse of the final project in the video after the break.

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Console Radio Given New Life With A WiFi Router Retrofit

April 23, 2013 by Mike Szczys 21 Comments

tube-radio-wifi-router-retrofit

[Craig] did a great job of restoring the case of his antique console radio. But he wanted to bring the guts up to modern standards. The fix ended up being rather easy when it comes to hardware. He based his internet radio retrofit around a wireless router.

We laughed when we heard that he removed about eighty pounds of original electronics from this beast. He then cut a piece of MDF to serve as a mounting platform for the replacement hardware. The WiFi router takes care of audio playback from several sources and offers him the ability to control the stereo from a smart phone or a computer. It has a USB port to which he connected a hub to make room for the USB sound card and a thumb drive which holds his music library. The black box in the upper right is an amp which feeds the NHT stereo speakers housed in the lower half of the cabinet.

It doesn’t make use of the original knobs like the recent tube-amp conversion we looked at. But [Craig] did add some LEDs which illuminate the dial to help keep that stock look.

Tube Radio Husk Gets A Web Radio Transplant

April 16, 2013 by Mike Szczys 36 Comments

[Dominic Buchstaller] found this German Greatz tube radio at a flea market. It only cost him about €35 and was in a bit more rough condition than the finished product you see above. He also found that a portion of the original circuitry was missing, making it completely non-function. He cleaned up the case to improve the wife-acceptance-factor, and outfitted it with hardware to make it a web radio.

Adding modern speakers was pretty easy as he was already replacing the original cloth bezel which has several holes and tears in it. A set of elements from some Logitech computer speakers served as the organ donors for this step in the process. As he was trying to keep a stock look he came up with a really neat hack to use the original knobs. The station select happens to have a large metal wheel on the inside which is about a centimeter wide. [Dominic] used the optical sensor from a mouse to monitor the turning of the dial by aiming the sensor at this wheel. Internet connectivity was provided by a wireless router he had on hand. This way he can stream music or play from an SD card he also used in the retrofit.