Retrotechtacular: A tour of WLW, a 500,000 Watt radio transmitter


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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Water cooled Raspberry Pi


If your Raspberry Pi is running a bit hot you can add a few hunks of salvaged heat sink, or you can go all out and machine your own water cooling system.

Remember when everyone had a giant desktop computer which was a perfect receptacle for cool lighting effects and somewhat ridiculous cooling systems? Relive that experience with [Phame's] multi-page forum post that serves as the build log. With the exception of the tiny pump itself, this one’s a fully custom job.

The image on the left shows the machined parts being tried on for side. There is a slug which contacts the ICs on the RPi board, conducting the heat to the chambers inside through which the liquid will flow. The upright rectangular enclosure serves as the reservoir which dissipates the collected heat as the water flows through it. The image on the right shows the finished project. It uses the power pins on the GPIO header to drive the pump.

[Thanks PL via Bit-Tech]

Induction furnace

induction furnace

[Tim Williams] made his own induction furnace. A copper tubing coil forms the primary winding, as the material to be heated becomes the short circuited secondary. The load material is subject to high power magnetic fields operating at radio frequency. The rapidly changing field induces current flow within the material, creating a great deal of heat. The brute power required a cooling system to match. In the video below, the induction furnace can be seen melting common table salt.

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