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#21
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CFII oral exam guide questions?
too difficult to comprehend for the beginning student who is not an
electronics major BT "John R. Copeland" wrote in message .. . "Jose" wrote in message . com... Well, Jim, it almost COULD work that way, but it doesn't. :-[ VOR azimuth angle is measured by a phase comparison between two sinusoidal signals, not a time-delay measurement. The VOR reference signal is frequency modulated on a subcarrier, while the azimuth signal is from amplitude modulation on the radio-frequency carrier, caused by the VOR's rotating cardioid beam. It's indirect, but isn't a measurement of phase difference of two different waves the same as the measurement of the time difference between crests (once you take into account the frequency and the speed of light)? It's like saying the alimiter measures altitude. It's not technically correct (and yes, the difference is meaningful under some circumstances) but gets the job done. Jose -- The time domain and the frequency domain are related conventionally through a mathematical manipulation called the Fourier Transform. However, the measurement methods used in the two domains are considerably different. The VOR system was designed for measurements in phase space. DME, of course, was designed for the time domain. |
#22
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CFII oral exam guide questions?
Capt. Mike wrote: Who cares how it works ? R u going to build one or fix one ? Know how to operate the equipment and not how the equipment operater - I'm not sure if I'm spending hours with my instructor learning trivia or useful stuff. However, this is a CFII and not an IR checkride so the standard for understanding and being able to explain is different. -Robert |
#23
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CFII oral exam guide questions?
The time domain and the frequency domain are related conventionally
through a mathematical manipulation called the Fourier Transform. That may be true, but is also a ten dollar irrelevancy. The phase difference directly relates to the time difference. Operationally, the circiuitry employs phase relationships rather than a little man with a fast stopwatch, but new pilots attempting to understand the concept of VOR navigation don't need to understand RF electronics to "get" the idea behind the VOR, especially in contrast to the ADF or DME. I find the analogy completely apt. The VOR system was designed for measurements in phase space. DME, of course, was designed for the time domain. This is a useful distinction for ciruit designers, but not for new pilots. Jose -- The price of freedom is... well... freedom. for Email, make the obvious change in the address. |
#24
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CFII oral exam guide questions?
On 13 Jun 2006 08:23:09 -0700, "Robert M. Gary"
wrote: Mitty wrote: You might look at: http://www.dauntless-soft.com/PRODUC...?DMODE=FAATEST I have used their software for written tests and found it to be very good. I tried the "RideReady" Commercial oral package when it was very new, a couple of years ago and at that time I thought it was kind of weak. They don't appear to have anything for the CFII . Ahh...yes they do...it's part of the instrument rating s/w, not the CFI/FOI package. I've used several of their test and oral prep packages and found them to be extremely good value for the $$... The oral exam (Ride Ready) preps still worth the $$, not quite as good as the test preps. --Don Don Byrer Radar Tech & Smilin' Commercial Pilot Guy Amateur Radio KJ5KB kj5kb-at-hotmail.com "I have slipped the surly bonds of earth; now if I can just land without bending the gear..." "Watch out for those doves...smack-smack-smack-smack..." |
#25
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CFII oral exam guide questions?
In article ,
Jose wrote: The time domain and the frequency domain are related conventionally through a mathematical manipulation called the Fourier Transform. That may be true, but is also a ten dollar irrelevancy. The phase difference directly relates to the time difference. Operationally, the circiuitry employs phase relationships rather than a little man with a fast stopwatch, but new pilots attempting to understand the concept of VOR navigation don't need to understand RF electronics to "get" the idea behind the VOR, especially in contrast to the ADF or DME. I find the analogy completely apt. I honestly don't see why a pilot needs to know anything beyond, "A VOR transmits 360 radials, and the NAV receiver can tell which one you're on". Unlike some of the physics half-truths the FAA pushes, I can't see how this little white lie could possibly get you into any operational trouble. It doesn't get in the way of understanding VOR declination, or service volumes, or scalloping due to signal reflections, or reverse sensing, or the zone of confusion, or any of a number of little VOR gotchas that pilots do need to be aware of. |
#26
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CFII oral exam guide questions?
Robert M. Gary wrote:
Know how to operate the equipment and not how the equipment operater - I'm not sure if I'm spending hours with my instructor learning trivia or useful stuff. However, this is a CFII and not an IR checkride so the standard for understanding and being able to explain is different. I've been teaching instruments for a few years, and I think you're learning useful stuff. If you don't understand how the equipment operates, the only way you can learn to operate the equipment is by rote. If you're always flying with everything multiply redundant, always flying with the same stuff, and can simply squawk anything out of the ordinary and make it someone else's problem, you can get by that way if you're willing to memorize a lot. It's an airline pilot sort of attitude. It doesn't work too well in GA. The people we train often have only one of something, and thus an understanding of how it works - and thus of the failure modes - helps detect failures and understand their impact on the operation. They usually pay for their own maintenance, and often participate in the maintenance process, and thus being able to diagnose the failure is valuable. They also upgrade equipment, and understanding how it works means not needing to be retrained on every new item. Michael |
#27
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CFII oral exam guide questions?
"Jose" wrote in message . com...
The time domain and the frequency domain are related conventionally through a mathematical manipulation called the Fourier Transform. That may be true, but is also a ten dollar irrelevancy. The phase difference directly relates to the time difference. Operationally, the circiuitry employs phase relationships rather than a little man with a fast stopwatch, but new pilots attempting to understand the concept of VOR navigation don't need to understand RF electronics to "get" the idea behind the VOR, especially in contrast to the ADF or DME. I find the analogy completely apt. The VOR system was designed for measurements in phase space. DME, of course, was designed for the time domain. This is a useful distinction for ciruit designers, but not for new pilots. Jose -- Jose, you asked and I answered. I didn't disagree with you. The truth is out there for those who are interested. But Jim's DME explanation was egregiously wrong, and shouldn't propagate. |
#28
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CFII oral exam guide questions?
"Roy Smith" wrote in message ...
I honestly don't see why a pilot needs to know anything beyond, "A VOR transmits 360 radials, and the NAV receiver can tell which one you're on". Unlike some of the physics half-truths the FAA pushes, I can't see how this little white lie could possibly get you into any operational trouble. It doesn't get in the way of understanding VOR declination, or service volumes, or scalloping due to signal reflections, or reverse sensing, or the zone of confusion, or any of a number of little VOR gotchas that pilots do need to be aware of. This is usenet so we like to split hairs. :-) VORs are not limited to "360 radials". If you want to claim you navigate to 1/2-degree precision, or finer, VORs do that. Personally, I try not to claim that ability, though. :-/ |
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