Leaderboard

Time to make friends with the neighbors who own EVs.

I disagree with just about all of Rep. Cheney's policy positions, but to punish her for not promoting a huge lie is about as low as you can go.

All true but this is Speakers Corner. I have, admittedly, achieved a certain degree of financial security through an odd combination conflicting of galling hypocrisies and inadvertent good works. From what I hear, you went to school. Happy though we each are with our respective outcomes I, as humbly as I can, respectfully submit that those among and above us who are somehow able to scrape together another $50 Billion or so while my favorite sushi chef is collecting dinner at the local food bank ought to be paying a crap load more. Especially if it is futile and punitive.

My understanding is that it will probably be the end of the week until the pipeline is restored. Then likely another few days to build stocks back up. The shortages are largely caused by panic buying. this should be a wakeup call to everyone about how vulnerable supply chains are. I'm not really sure why it is turning into another partisan issue here. It could pretty much have happened anywhere. It is a criminal act.

I’d include the names of who you jumped with; someday in the future you’ll read that logbook for reminiscing purposes, and that’ll be key. Also a short comment when it’s particularly fun, exciting, or something else like that happened. Wendy P.

Sweetie, you don't empower women, they own the power. It's not yours to give. Wendy P.

Yep. If he turns out to be a boring chief executive who spends his time in meetings, on the phone and in Congress, it will be a huge improvement.

Interesting hypothesis. Do you have any proof? Why do I not see giant plastic research ballons on my radar scope, then. I've worked dozens of missions with them at Tillamook, OR. Your talk of how radar works is correct, although mine doesn't use the Doppler effect, but to say that something is transparent to radar but also a good reflector sounds illogical. However, I have observed temperature inversions bending radar (think mirages) but that is much different than reflecting radar. What I am saying is that in general terms - air does not effect radio waves (this is actually untrue, particles in the air do but as a level that takes it out of the scope of this conversation). However, if air causes another material that would reflect radio waves (nylon) to take a different physical shape (in this case making it a flat plane) then the originally very weak and scattered reflection becomes more concentrated and it is more likely that a receiver looking for the signal is able to pick it up. Technically speaking, all radar technology needs to consider the Doppler effect. Radio waves are everywhere, from every directions. Even your cell phone emits a signal that travels forever if nothing absorbs it. The further away from the transmitter, the more spread out the electromagnetic radiation becomes, causing the signal to be more difficult to identify. In order to transmit and receive signals with accuracy, radio technology as we know it uses a carrier frequency and different forms of modulation. The most common knowledge modulation types are AM (Amplitude Modulation) and FM (Frequency Modulation). Radar radio doesn't need to carry any more information than is necessary to be able to identify itself when listening to the echo. If you bounce a certain frequency (using unproportional figures for simplicity) off of an object that is not moving at say 10MHz - your echo will be 10MHz. However if that object is moving away from you, the frequency becomes slower - lets say 9.9MHz. If that object is moving closer to you, the frequency becomes faster at 10.1MHz. This is the Doppler effect, and can also be noticed with sound (the textbook example is when a police car drives past you, the siren on his car changes tone slightly from a high pitch, to a lower pitch) Again, these numbers are for the sake of example... the actual change would be much much smaller. A radar can't take a "snapshot" to detect anything. It requires time to work. Radio frequency is quite high, you can receive 100 million wavelengths a second - so from our perspective it seems to work instantly - but it needs to receive the signal for long enough to lock on to the carrier frequency, and then determine small changes in frequency. This is all done with analog electronics because digital computers of today are not powerful enough to make this calculations. Various techniques can be used to assist in making sense of weak signals. One of these is to look for patterns that would represent signals reflecting off of a flat surface that was not at an exact 90 degree angle. These types of analog circuits are commonplace in electronics; but are most commonly implemented in the design of the antenna. The round nature of a balloon is not something most receivers are designed to accomodate (not that it couldn't but it would be a lot of extra unnecessary engineering for most common radar practices). This would explain why an inflated parachute would be more likely to be picked up than a weather balloon. It all comes down to what a particular radar was designed to look for. ATC radar systems may or may not be able to pick up single skydivers. I would be surprised if they did, as they're looking for larger items. They have a larger chance of being able to see a deployed ram-air parachute. The point that I was trying to make is that the air pressure inside of a ram air canopy *would* indirectly make a physical difference in a radar being able to detect that parachute because air is what is giving the parachute a close-to-flat surface, and that most radios are designed to receive signals being sent from (antennas) or reflecting off of (airplanes) relatively flat surfaces. As any radio expert would tell you, what I wrote above isn't 100% accurate from the perspective that I left a lot out about concepts involved in receiving signals... But that was my best job of explaining why the air inside of a ram-air canopy would contribute to the entire parachute becoming easier to see on a radar than if it was not inflated. - without writing a book on radio. While I'm not a professional with radio (I've never made money doing it), about 5 years ago I actually built a radio that I used to measure the distance between the earth and moon by reflecting signals off it. and, It was only a 5 watt transceiver. My original intention was to make a clock that would teach itself what time it was over a few days time based on light changes, and measuring the position and distance of the moon... I only got as far as measuring the distance between the earth and moon before I got bored with the project. Took me about 2 weeks of free time. Matt Christenson [email protected] http://www.RealDropzone.com - A new breed of dropzone manifest software.