Hot answers tagged

27

I think this is an example of a counterpoise: [It] is a network of suspended horizontal wires or cables (or a metal screen), used as a substitute for an earth (ground) connection in a radio antenna system (...) when a normal earth ground cannot be used because of high soil resistance or when an antenna is mounted above ground level. Generally used for LF ...


26

I would imagine the main reason is to make the performance of the antenna system more predictable and consistent. Many antennas systems need a ground reference. All antenna systems are affected by nearby conductors. Using the grounds surface as your ground reference has a few issues. It means your antenna system is at ground level. That means any nearby ...


19

A radial is always pointing (radiating) away from the VOR. But your instrument shows the TO/FROM indicator as TO. So you are crossing a 210 course towards the VOR, which means you are on the 030 radial from the VOR. What does it mean to be crossing a radial? This just refers to the fact that you cannot determine your heading (or track) from the CDI. Based ...


18

In Canadian Airspace, Northern Domestic Airspace (NDA) is the area of compass unreliability within which runways and NAVAIDs are oriented to true or grid north versus magnetic north. You should not need to worry about which NAVAID is to true north; simply keep track of whether you're in Southern or Northern Domestic Airspace.


17

There are no spinning parts in the VOR. It typically uses 60 antennae in a phased antenna array to steer the beam in a rotating sweep. The VOR transmits a constant omnidirectional signal. The phase of the secondary sweeping directional beam is varied in time such that it is out of phase with the constant signal by the same number of degrees from North. ...


17

Modern air transport and bizjet avionics do decode the audio ID and provide it digitally on the data output bus. This data is displayed on the Nav display or RMI (depending on Mode) along with the frequency. It's not as common for general aviation radios to have this capability. VORs that comply with ARINC Characteristic 711, VOR MB Receiver, output the ...


16

Modern VOR are Doppler VOR (which rotate in the direction of the one in your picture). The bearing signals are produced by a circular array of fixed antennas which diameter is 14 m and an additional central antenna. Thales Doppler VOR 432, source In the so-called dual sideband DVOR, antennas are used by pairs of diametrically opposed antennas, one pair at a ...


14

Yes, without a shadow of a doubt. Many airports now publish GNSS (Generic term for all types of satellite navigation) approaches, completly negating the need for those aids even during complex, critical phases such as approach and landing and take off and departure. Modern GNSS systems are capable of utilising synthetic VORs where even when doing something ...


13

VOR stations in areas of magnetic compass unreliability are oriented with respect to True North. I don't think you can tell if it's pointing true north by looking at the charts. However, it doesn't really matter anyway because your own compass would be unreliable as well when flying in the vicinity of such a VOR. After all, when navigating using a VOR, you ...


13

No, it should not be used. Twin antennae, as you have shown, are balanced and fed into a balun (BALanced to UNbalanced) to feed the single transmission line to the receiver. Together, they provide the correct impedance for the aerial system. With an antenna broken, it is likely that the impedance of the circuit is wrong and therefore, the input to the ...


12

It says it right there on the page where the service volumes are described in the AIM: 1-1-8. Navigational Aid (NAVAID) Service Volumes c. Standard Service Volume limitations do not apply to published IFR routes or procedures. So V267 has been flown at the MEA by an FAA plane, and it obviously met the signal accuracy requirements to be usable at ...


12

Nice question. There are several ways how to get these information. http://www.fallingrain.com/: free to use, no registration needed. World database of the airports and waypoints. From these information you could easily make DB for waypoints. EUROCONTROL EAD (https://www.ead.eurocontrol.int/eadcms/eadsite/index.php.html): free to use, registration needed. ...


12

As pointed out in the comments, I think you have things turned around. If you select the frequency of a VOR that has a co-located DME, the system will automatically also select the DME frequency. Thus, I'm guessing that what you perhaps meant to ask is under what conditions do you manually tune the DME frequency. If that is NOT what you are asking, put a ...


12

Yes, it is true. This FAA page has more info. The Very High Frequency Omni-directional Range (VOR) Minimum Operational Network (MON) provides a conventional navigation backup service in the event of a loss of Global Positioning System (GPS) signal. The MON includes the minimum number of geographically situated VORs in the contiguous United States (CONUS) ...


11

Many older Air Transport Airplanes have no GPS. I'm a pilot since 1970. I operated A330 for 5 years until 2000 without GPS. The average IRS position (Inertial Reference Systems) in the FMS was updated by DME/DME. On older airplanes we selected the DME Stations manually preferably with a 90 degree cut-angle to obtain an accurate update. A single VOR/DME ...


11

You are correct that VOR's rarely have a range of more than 200 NM. However, Alta Floresta VOR (ATF) is colocated with an NDB (and DME). In spite of less accuracy, NDB's have a much greater range (partly because their signals can travel as ground waves). This makes it possible to have a very long segment on the G678 airway without other navigation aids. When ...


10

In the US they can (Effective: May 26, 2016). This change allows for the use of a suitable RNAV system as a means to navigate on the final approach segment of an instrument approach procedure (IAP) based on a VOR, TACAN, or NDB signal. The underlying NAVAID must be operational and monitored for the final segment course alignment. Still can’t fly an ILS or ...


10

Your example is a bit confusing because it seems to be a GPS-based route, it may be better to a look at a more 'realistic' one, where you're using only VORs for navigation. The reason to tune a second VOR is to cross-check your position, either by crossing a specific radial or perhaps by using DME (for a VOR/DME or VORTAC). If that's useful to you then you ...


9

In areas of large magnetic declination, approaches and runways are given in true instead of magnetic headings, designated by T after the heading, such as RNAV 13T approach. If you are assigned a VOR radial, just follow that radial whether it is true or magnetic. The important thing is that you don't use magnetic headings on a true approach. Look out for ...


9

JFK ARR ILS 22L/22R DEP 22R If conditions dictate the use of JFK ILS RWY 22L approach, then (1) the JFK Area owns Belmont airspace 3,000' and below, (2) releases Coney airspace to LGA and LIB, (3) JFK cannot depart 31L, (4) ILS 22R unavailable if LGA departs RWY 13. LGA ILS 22, DEP 13 LGA Coney, Maspeth, and Whitestone climbs are available. LGA ILS ...


8

The dot in the center of the star means that there is a rotating beacon available on the airport from sunset to sunrise. See the FAA Aeronautical Chart Users Guide Page 8. The actual center of the VORTAC is the small dot between the runways: Which you can find the description of in the chart users guide on page 8 as well:


8

Do they generate the same navigation signal? The DVOR reverses the useage of the two 30Hz signals. However, by also reversing the direction of it's rotating variable signal it produces exactly the same result in the receiver. The receiver has no "knowledge" that it's a DVOR as opposed to CVOR it's receiving and operates as normal. Can they be used by the ...


8

I use the National Flight Data Center at http://nfdc.faa.gov I had to write them a letter explaining why I wanted the data (http://fplan.sf.net) and they provided me with a login. Now, every 56 days, they send me an email telling me there's an update available. Bad news: they recently switched from a flat file to some unbelievably convoluted xml format ...


7

Your basic understanding of the underlying electronic principles is correct: The VOR receiver detects a phase offset between two signals, which tells the receiver what radial the aircraft is currently on. Wikipedia has a decent explanation, and this article on Digital Flight Instructor has a nice widget you can play with to see the frequency offset. The ...


7

The value +/-40° is correct, but need to be interpreted. The primary reason of the existence of a "silence" cone is a design choice to increase navaid range. Range and "isotropy" are antagonistic. For the D-VOR there is a second reason: The lack of Doppler effect around the VOR zenith. Detailed case: D-VOR A VOR radiates a signal that can be interpreted in ...


7

No, you still have to monitor the underlying NAVAID. You just have to read further in that same section of the AIM. Reference the most recent edition of the AIM, which has Change 3 dated April 27, 2017. In section 1-2-3-c-5 it says: Use of a suitable RNAV system as a means to navigate on the final approach segment of an instrument approach procedure ...


7

Does this clearance allow me to fly a reciprocal of 020 inbound to the station? Or will I just have to fly away from the station on 020 radial? A radial is always pointing away (radiating) from the VOR. The clearance therefore instructs you to fly away from the VOR on the 020 radial. Will a left turn be more appropriate than a right turn to intercept ...


6

There are numerous options, and it depends highly on your route. But there are generally enough VORs scattered across the country such that you should be in range of a couple of them pretty much everywhere. As mentioned in another answer, there are NDBs, but in the continental US, generally, the ones not on an approach are getting fewer, as the FAA has ...


6

Isn't it too much? No, it isn't. VOR's and NDB's are pretty old technology. VOR's were introduced in the 1930's and 40's, but are still commonly used today. If you have a cone of confusion of 45 degrees to all sides, this means that, at 40.000 feet, the signals will be unreliable within about 6 miles from the beacon - which isn't really that much. At lower ...


6

In the US, the FAA has done this alot, as in their long term plan to phase out a lot of the VORs. Doing that, they're preemptively just adding a Fix for procedures on top of the VOR so they don't have to update all the procedures when the VOR is decommissioned.


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