25
votes
Accepted
How does the ADF null positions find where the NDB is?
Short answer
Do you find the null position, then assume it's 90 degrees from the
beacon?
That's correct. For the antenna pattern shown in the question, the angle between direction of nulls and peaks ...
- 68.6k
23
votes
Why does a DME ground station wait 50 microseconds?
The delay is not 50 milliseconds, but 50 microseconds.
It takes some time for the ground equipment to decode the incoming signal, decide it needs to reply, and fire up its transmitter. In order for ...
15
votes
What are the differences between a VOR and a VORTAC?
VOR stands for VHF Omnidirectional Range. It is a navigation beacon intended for civil use and provides a user with a radial to/from the station. It works on frequencies between 108.00 and 117.95 MHz....
- 77.1k
13
votes
Accepted
Why would a VOR be decommissioned leaving the DME?
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 ...
11
votes
Accepted
What's the meaning of underlined frequency in sectional chart nav aid box?
Navigation receivers can be used as a fall back for regular VHF/HF radio transceivers
Before data links, there were essentially two types of radio receivers in the flight deck, and this is still the ...
- 68.6k
11
votes
Accepted
Are there two navaids on the same frequency close enough to be confused?
Short answer
ICAO recommendations include a protection for same-frequency navaids, restricting the received power of undesired stations to a level preventing interferences. To meet this restriction ...
- 68.6k
10
votes
Why would an ILS installation need a “reflecting surface” around the glideslope antenna?
You wrote that
intuitively, one would expect that UHF-radio-wave-reflecting surfaces near your glideslope antenna would be a bad thing, due to the potential for multipath interference
However, ...
- 2,815
9
votes
Accepted
Why do IFR charts show TACAN paired frequencies when there is no collocated VOR?
Your supposition is correct. Tuning the paired frequency will allow you to receive DME information from the TACAN.
If your DME tuning is through your VOR/ILS receiver, the VOR output will be flagged ...
- 18.5k
8
votes
How do you know if a VOR is High, Low, or Terminal?
The range of the VOR is included in the Airport/Facility Directory data under the name class
From A/FD legend:
Example:
Service volume for each class:
- 68.6k
8
votes
Accepted
What does the crosshatching mean on this VOR-DME?
You're right. From FAA Aeronautical Chart User’s Guide,
NAVAIDS in a shutdown status have the frequency and channel number crosshatched. Use of the NAVAID status “shutdown” is only used when a ...
- 99.4k
8
votes
Accepted
Where does the Garmin G1000 Nav ID come from?
Garmin doesn't explicitly state the method in the documentation I can find, but I believe the answer is #1. It decodes the Morse code and displays that value. I say that for two reasons:
First; ...
- 18.5k
8
votes
What is the difference between unserviceable, unusable, and not maintained?
UNSERVICEABLE (abbreviated U/S) is the ICAO version of what the FAA used to call OUT OF SERVICE (abbreviated OTS). To my mind this is less clear and a step backwards, but at least it's in line with ...
- 12.2k
7
votes
Accepted
What, effectively, does a navaid being unmonitored mean?
Actually it doesn't have anything to do with voice capabilities:
5-3-5. UNMONITORED NAVAIDs
a. All VOR, VORTAC, and ILS equipment in the NAS have automatic monitoring and shutdown features in the ...
- 35.8k
7
votes
Accepted
What is magnetic variation under RADIO AIDS TO NAVIGATION in FAA Chart Supplement, and How to use it?
Conceptually, VORs (and VORTACs) emit radials which are fixed lines radiating out from the VOR. One of those radials is designated "north" (0º, 360º) and all of the other radials are ...
- 12.2k
6
votes
Accepted
Why does a DME ground station wait 50 microseconds?
the purpose of the 50 microsecond delay is to eliminate the possibility of uncoordinated operation when the aircraft is very close to the ground station
From AVweb - DME Basics
Addendum
I have not ...
- 26k
6
votes
Accepted
What official government document should a pilot check to determine what magnetic north a VOR was set to when it was commissioned?
The chart supplement does list the magnetic variation of the VORs. Looking under the "radio aids to navigation" section for a nearby airport, it's listed at the end of the line, right after the ...
- 70.6k
6
votes
What kind of input is used by NASA's TASAR?
The answer is "All of the above." The left hand side of this slide from a NASA Powerpoint deck pretty much covers your question.
The full slide deck from the presentation can be seen here.
- 12.2k
6
votes
Accepted
Is it true that there are VOR/DME and/or TACAN stations in the oceans?
There are no ship-based VOR's or TACAN's specifically dedicated to transatlantic flights. Transatlantic flights navigate using the inertial navigation system and GPS.
TACAN's are used on board naval ...
- 77.1k
6
votes
Is flying direct to a navaid considered a leg with track guidance?
I see that if a specific course is not required, the aircraft will turn direct to the navaid on any course which is suitable with its performance. But the aircraft always have track guidance regarding ...
- 21.8k
5
votes
What is the minimum separation for navaids to work properly without interfering?
VOR/DME and NDBs can't interfere with each other: they work on completely different wavelengths, so you could have a VOR right next to an NDB and they'll work just fine. Similarly, VORs on different ...
- 52.1k
5
votes
How do you know if a VOR is High, Low, or Terminal?
Typically terminal VOR's do not have compass roses around them if they are strictly terminal VOR's. I can't find an example of one so I don't have an image for it.
Edit I found an example:
Source: ...
- 35.8k
5
votes
Accepted
Why are the VHF and UHF airbands directly adjacent to frequency bands used by vital radionavigation aids?
The most obvious reason is that the ITU allocated the VHF and UHF bands for aviation purposes generally, and then aviation authorities had to split those limited bands into adjacent comm and nav sub-...
- 27.4k
5
votes
Accepted
Why do none of the procedures for EFSA use the SVL VOR-DME?
According to the Finnish AIP, LINNA (SVL) is only a DME, not a VOR/DME.
- 716
4
votes
Accepted
How are Victor airways defined and numbered?
The general rules for this are in FAA Joint Order 7400.2K, Procedures for Handling Airspace Matters. Chapter 20 describes when and how air routes are defined and designated, although it doesn't go ...
- 71k
4
votes
Where to find a waypoints/fixed points, navaids and airports database?
Another good one for airports and navaids: http://opennav.com/ - has VORs, waypoints, etc.
- 141
4
votes
Accepted
What's exact offset degree dividing localizer and LDA?
The maximum angular offset for a LOC is 3° for FAA and 5° for ICAO. Everything else is named either LDA (FAA) or IGS (ICAO).
In ICAO wording, any ILS which doesn't meet all ILS requirements is an ...
- 68.6k
4
votes
What are the units for the bearing to center of an airport from radio aids to navigation in chart supplement?
It's almost certainly magnetic. Page 12 of the Chart Supplement (sample airport information) has this information at the bottom (emphasis mine):
All bearings and radials are magnetic unless otherwise ...
- 71k
3
votes
Reason for the multiple sidelobes in an ILS glideslope signal
All directional antennas have sidelobes (and all real antennas are at least somewhat directional). I won't get into detail of the fundamental physics reasons behind that, as that's beyond the scope of ...
- 4,631
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