Emergency Gadgets Reviewed

Carl Bialik writes "When power lines go down, hand-cranked radios and standalone cellphone chargers could come in handy. Wall Street Journal columnist Walt Mossberg reviews emergency gadgets, including a $50 radio that picks up TV audio and gets 35 minutes of power from a 30-second crank. Of course, Mossberg also offers the caveat that these gadgets could be rendered useless 'should the communications infrastructure itself go down.'"

Comments

Baylis generator = no batteries at all

[jakedata]

I have been using my original Freeplay radio for about 8 years now.

Unlike the more recent models, it operates on a spring driven generator for about 45 minutes, or in sunlight. It has no internal batteries at all.

The lack of batteries is a Very Good Thing. Rechargable batteries die, and sometimes they short out. If so, you got no radio - cranked or solar.

The downside is that the radio is the size of a loaf of bread. The upside is that it has a very large speaker and very nice sound.

I toyed with the idea of adding an external power tap, but there are dire warnings about opening it up and releasing the giant spring. Someday perhaps...

Re:Baylis generator = no batteries at all

[stefanlasiewski]

Freeplay still makes an AM/FM/SW1/SW2 windup & solar powered (no battery) radio, but it's mostly intended for rural African communities. But you can buy one and donate a second radio for the Freeplay Foundation.

It's the size of a loaf of bread, and it's ugly, but it's not really aimed for American gageteers.

cheaper, better hand-cranked radios

[Yrrebnarg]

Take a look at http://www.radios4you.com/ or http://www.kaitousa.com/ and invest in a radio that also does shortwave if you're looking for an emergency radio. For far less than the $50 you'd spend on the yuppie crud in TFA, you can pick up a solar/crank/charger model and a decent antenna reel, which would let you pick up broadcasts from europe, cuba, the USA, the caribbean (BBC news), or just about anywhere else. All you lose is _local_ broadcasts when the communication infrastructure takes a nose-dive.

Re:TV on Radio

[Phreakiture]

As anyone who has lived in the 3rd world can tell you, you can pick up TV on ordinary FM radios it is a matter of tuning it to the right frequency. I have seen these things in Asia for years.

This is 100% dependent on the frequency structure in the country in which you are located. To do this with an "ordinary" FM radio in the US, you can only pick up channel 6, at 87.75MHz (with 87.7 being close enough). If you have one of the Japanese radios that has extended coverage to do both the Japanese 72-93MHz FM and the American/European 88-108MHz FM bands, then you can also get audio from US TV stations on channels 4 (75.75MHz) and 5 (81.75MHz).

There are other radios out there that have got TV audio capability on them. They frequently only cover channels 2-13 because it is easier to build a VHF than a UHF radio.

For reference, the frequencies are as follows:

Channels 2-6: 59.75, 65.75, 75.75, 81.75, 87.75 (note the gap betwen 3 and 4 is 10MHz, not 6MHz as elsewhere)

Channels 7-13: 179.75, 185.75, 191.75, 197.75, 203.75, 209.75, 215.75

Channels 14-69: 475.75, 481.75, 487.75, etc, every six MHz up to 805.75

Note also that frequencies within any vacant TV channels in the channel 14-20 range (470-512MHz) may also be licenced to business or public safety two-way radio users, especially in larger metro areas.

Last note, which I am providing to explain the huge gap between frequencies: the structure of a TV channel is this: It is 6MHz wide. The audio is 5.75MHz from the bottom of the channel, and uses the upper .5MHz of the channel (that is, 5.75MHz +/- .25MHz). The video is at 1.25MHz from the bottom of the channel to 5.5MHz from the bottom of the channel. Below the 1.25MHz point is cruft called a Vestigial Side Band. For example, on channel 2, 54.00-55.25 is cruft, 55.25 is the video carrier, 55.25 to 59.5 is video, 59.5 to 60.0 is audio, 59.75 is the audio carrier.