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Comment Re:Tips for a pirate radio operator... (Score 2) 157

I actually built and ran a pirate radio station in Tucson 15-20 years ago, Radio Limbo 103.3. I agree with your tip, but I took it a step further. The transmitter was a 1 watt unit that we hiked way up into the mountains north of town, giving it a 3000 foot elevation advantage. We transmitted through a Yagi made from a modified FM receiving antenna. The uplink was on UHF, and the rig was solar powered. It covered most of the city (about a 10 mile radius in the preferred direction) reasonably well.

The other thing we did, which really made the station great, was to get about a hundred DJs to volunteer for 1 or 2 hour slots, to make the programming interesting.

Comment Re:People say "custom-made" like it's a bad thing (Score 2) 474

It's difficult to even define standard interfaces that make sense 50 years in the future. But you have a good point - modular hardware is a lot easier to upgrade than complete systems. I work on a telescope that was originally built in 1965, so I get to replace bits and pieces of it with new stuff now and then. However, sometimes all I have to do is correct a little design mistake from way back when to get it running in tip-top form.

Comment Probably using a CHAMP-WB (Score 1) 122

Curtiss-Wright makes a circuit board that would be perfect for this work. This board is an FPGA next to a DAC that can spit out an RF signal whose modulation is about 6 GHz wide, calculated by the FPGA. Using this technology, ANY type of waveform or modulation can be sent to the radar transmitter.

I just ordered (for my radio astronomy job) its cousin, which is all A/D converter, as our radio telescope doesn't have a transmitter, just a receiver.

Comment Why is wetness even a problem? (Score 1) 74

The USB charging port is only 5V, and the resistance of water, even salt water, is high enough that it shouldn't disturb the charging process. I can see why you wouldn't want to submerge your 120V hair dryer in the bathtub with you, but this is a completely different scenario. Am I missing something?

Comment Re:Draft? None certified? Newegg disagrees (Score 1) 146

There are two logos one uses for UL stuff: The backwards UR which means a recognized component, and the UL which means a listed complete product. A claim that the battery being UL listed (if such a thing is even possible) constitutes the necessary safety testing is a bad move, as the entire hoverboard assembly needs to be tested and UL listed for it to have some hope of being safe enough for your insurance adjuster to buy you a new house when your hoverboard burns it down.

Comment Re:Stop promoting your own articles StartsWithABan (Score 1) 105

The adaptive optics system is quite something, if it's anything like the one at the LBT on Mt. Graham. They have been able to make diffraction-limited images with that one. When they turned it on for the first time, the results were so good that they thought it must have been an error. The downside is that it took about ten years to make the first adaptive secondary mirror and get it installed, as it's about 1m diameter and 1.6mm thick, with 600 magnets glued to its backside. A couple of them broke in transit before they figured out how to pack them properly. (I work in the same building as the GMT and the LBT folks.)

Comment Re:Physics puts enormous limits on using 30-300GHz (Score 4, Interesting) 33

I work in millimeter- and submillimeter-wave radio astronomy, where we receive signals in the 60 to 800 GHz range. There is a lot of water absorption of the signal, leaving only certain frequency bands usable. The semiconductors used at these frequencies are rather exotic - we use superconducting materials in our receivers for lower noise, and we cool them to 4 Kelvin. Making a power amplifier to produce even one Watt of signal at 75 GHz is a million-dollar project. In short, it's not likely to be mainstream for at least ten years.

Comment I was playing in a band (Score 1) 320

I was in a band called Warrren Frank's Current Name. We played in the Cellar, the U of Arizona Student Union hot spot, for the Eat To The Beat concert series that day. I heard the news on the radio of my 1959 Cadillac as I was driving the equipment over to the place at nine AM.
Naturally, our audience was all upstairs, watching events unfold in the big public TV set. It was all right, as the band was doomed anyways.

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