What does the "Range" in VOR mean?

[CaptLeslie]

Got a question that I could not answer, can anyone help?

VOR = VHF Omnidirectional Range

V = Very High Frequency - Ok got it no problem
Omnidirectional = all directions 360 degrees - OK got it no problem
Range = don't get it - where does this come from????

 

[52vincent]

Range = don't get it - where does this come from???? [/B]

Hope this helps:

Range = Range (distance from station) Its reception depends on the receiving aircrafts altitude as the signal is line of sight.Ranges vary from 25 to 200 nautical miles depending on the type of VOR.
Hence your types,
-Terminal
-Low altitude
-High altitude

If I understood what you asked for this should work.

or not

 

[CaptLeslie]

Yes - you did understand the question 52vincent .
Thank you for the answer!

 

[A Squared]

Capt. Leslie,

What 52vincent wrote does not answer your question.

Here's the deal: Range, in this case does not mean distance. Formerly, in navigation a "range" was a line of position. If you knew that you were on a range, you knew that you position was somewhere along a line. If you had 2 intersecting ranges, you could fix (determine) your position.

In nautical mavigation, you will still see reference to range markers, which are two highly visible panels, often lighted. If are in a position that the two panels line up, you know that you are on that range. Anyway, I've probably gotten way too involved here, but the basic concept is that a "range" is some line that you can determine that you are on. The old Adcock 4 course navaids were referred to as "radio ranges" When the VOR's came along, they called them Omniranges, because if you were within reception you could determine a range of position wherever you were around the VOR, as opposed to the Adcock, or A-N range where you could only determine a range of position if you were on one of four courses.

does that help, or have I just confused you?


regards

 

[80/20]

I agree with A Squared, "range" was a carry over term from the VOR's predecessor the "Four-Course Range" beacons, - used on our first Federal Airways. These beacons had a range of 100 miles and were located 200 miles apart. When the pilot reached the limits of one range, he tuned his receiver to the station located 100 miles due ahead on his course. As A Squared suggests, I believe the name range in it's very first context in 1926, probably referred more to the fact the there was a range of stations forming an airway. I also think they initially thought of "range" in the term that it means a series of things along a line (even though they were actually not on straight line). The ability to at least get some distance information besides station passage was achieved by introduction of radio marker beacons a few years later.

 

[A Squared]

From the Glossary of Bowitch's The American Practical Navigator:


range, n. 1. Two or more objects in line. Such objects are said to be in range. An observer having them in range is said to be on the range. Two beacons are frequently located for the specific purpose of forming a range to indicate a safe route or the centerline of a channel. See also BACK RANGE, LEADING LINE, MAGNETIC RANGE, MULTIPLE RANGES.

 

[80/20]

A Squared - are you thinking that they could have meant "range" as in "along a straight line"?

 

[A Squared]

A Squared - are you thinking that they could have meant "range" as in "along a straight line"?

Yeah, I believe that is the origin of the "range" in VOR. When you think about it, whether you're in a boat lining up on two lights on shore, or placing yourself on a leg of a four course radio range by listening to the dashes and dots, or placing yourself on the 037 radial of a VOR, you're really doing the same thing, putting yourself on a line of position, or range. You're just using different methods to accomplish the same thing.

regards

 

[bobbysamd]

VOR

It stands for VHF Omnidirectional Radio Range.

I second the other comments about the derivation of Range.

Long before VORs, in the days of Ernest Gann and his DC-2s, there was a system of airways based on NDBs. The avonics equipment used to navigate these airways wasn't anything like ADF receivers that (some of) you (may) know. These had loop antennas that you had to rotate manually to find your direction (I believe the saying was that to determine the range's position you should imagine the range's beam shooting straight through the loop). NDB airways are mostly extinct in North America, but there may still be a few in Alaska and Canada. Also in the Carribean, where they're identified by colors.

Shall we now have a discussion on compass locators, fan markers, and bone markers?

 

[80/20]

I was thinking a range of stations along an airway, just like several mountain peaks forming a mountain range that is not straight. But I agree with you A Squared. When they talked about ranges they must have meant a station that projected four straight-line courses (which we call radials today).
Omni is Greek and means all, so omnidirectional range can be explained as radials in all directions.
Good information A Squared!!!

 

[skiddriver]

Here's an excerpt from this page

http://www.aerothai.com/education.htm

which explains how the old range beacons worked.

Early 1920 the US Government introduces the first radio navigation, Four-Course Radio Range. This four course radio range transmit letter "A" and "N" in Morse code for the different sector. If the two transmission overlaps, the dot-dash (A) and the dash-dot (N) , of equal strength, would produce a constant tone in the pilot's headset indicating the aircraft is on the right track. If any deviation occurs in the course, a distinct tone of "A" or "N" would be heard depending on which sector it is on.

The disadvantage in the system is the inability to identify which sector of "A" or "N" it is on. This was later abolish and Marker Beacon was install in its place to provide a more precise navigational aid.

So, if you were on the range line, your nav radio gave you a solid tone. If you strayed left or right, you got either a dot-dash or a dash-dot, which cued you as to which way to turn to correct. As stated earlier, the VOR gave you an omnidirectional (360 degree) nav solution, instead of just the 4 range lines on the old system.

 

[A Squared]

More Adcock Range trivia

The last operational 4 course radio range in the US was in Northway, Alaska. It was decommissioned in 1974. They continued in use later in Canada and Mexico. I've heard that there are still some operational ones in Mexico, but it may be just a rumor. The five towers of the Nome Radio Range are all still standing. They are now supporting the antenna for the Fort Davis NDB. There are a number of NDB's around the US which are supported by one or several towers from a former Radio Range.

Bobby, the L/MF "colored" airways are still very much alive in Alaska, Canada, and the Carribian.


regards

 

[414Flyer]

THere are some some of the concrete arrows in the ground in New mexico that predates the radio range, or maybe all the radio navaids.

The were about 10 miles apart, and had a beacon light that flashed a morse code identifier.

The arrow pointed the way to the next arrow/beacon light.

There is one about a half mile from the Albuquerque VOR, and one right along I-40 in Gallup but you have to be in the air to find it

 

[flywithastick]

Four-Course Radio Range.

My uncle has told me about his days of flying around in F-80's, 84's, 89's in the weather or dark trying to hold formation and navigate with those things. Apparently you sometimes had to pass over the station a couple of times to accurately locate yourself WRT the station. Talk about tricky! and some current aviators complain about using NDB's.

 

[52vincent]

Well....you know how big I feel!!Just trying to help..That's why I put the caveat at the end. I had afeeling there was more to it.

Thanks for correcting me

 

[CaptLeslie]

Thanks a lot you all - what knowledgeable group! …I think we have a conclusion on what range describes in this context even though the word could have several meanings. We ended up with a discussion that at least I learned from. It's what's right that matters and not who's right - so don't be too hard on yourself there 52vincent!

Bobbysamd: Shall we now have a discussion on compass locators, fan markers, and bone markers?

Yes please - come on guys pour out some more of that knowledge & wisdom that we can't find in the modern textbooks!!

 

[80/20]

Photo of a Four Course Radio Range

 

[bobbysamd]

Non-VOR navaids

Quite a few of them could be found in the AIM at one time.

Compass Locators: (found at Smart Regs glossary ) - compass locator

A low power, low or medium frequency (L/MF) radio beacon installed
at the site of the outer or middle marker of an instrument landing
system (ILS). It can be used for navigation at distances of
approximately 15 miles or as authorized in the approach procedure.
a. Outer Compass Locator (LOM). A compass locator installed at
the site of the outer marker of an instrument landing system.
b. Middle Compass Locator (LMM). A compass locator installed at the site of the middle marker of an instrument landing system.

Fan Markers: (found at this link )

Fan markers are very similar in function and appearance to the ILS marker beacons. The primary operational difference is that they usually identify with a single morse code letter.
Fan markers can be used in conjunction with a Simplified Directional Facility (SDF) approach, or they may be used to mark some other important point in an approach or departure procedure.

Bone Markers: (found here )

Or Dumb Bell Marker because of its shape gives a more precise check when exactly on course. At 1000’ it is 3 NM wide in the center and 12 NM wide.

I believe that bone markers were used to mark fixes on the old NDB airways were were discussing above.

 

[80/20]

I will try to supplement Bobbysamd with some history the way I remember it. When I say remember I mean information that I have read or heard. So take it for what it's worth, I have not flow the old range, and my experience is limited to hand tuning ADFs manually. My old morse-code instructor told stories about flying the range.

First - why did they not use ADF more in the early days?
Homing devices were developed during World War I but they had many limitations and required "sophisticated" airborne radio-navigation equipment and special antennas. The only airborne equipment needed to use marker beacons and four course range stations was one simple audio radio receiver.

Where did the name "marker" come from?
The first transcontinental route between New York and San Francisco used bone fires along the route. The airway between Dayton and Columbus had 72 miles with rotating light beacons, floodlights and flashing markers. The lights were initially managed by the Light-house Bureau who knew a lot about surface ship travel but little about three dimensional flying. As A Squared points out, many aviation terms have maritime origin. They experimented with rotating beacons and course lights. I am not sure if they had a clear single definition of the word "marker" because they used it in several ways; to mark a position along a course, various colors and rotating light beacon speeds to, identify fixes, emergency fields and so on.

The radio ranges were introduced in the late 1920's and were shortly supplemented with radio marker beacons. The name radio marker beacon was used in this context to illustrate that it marked positions along an airway.

Where did the word "fan" come from?
The non-directional markers were acceptable for airways but of limited value for approaches. Better directional markers with a narrower signal were invented. I believe the word fan was used to describe the vertical beam, which was shaped like a spread out female hand fan.

How were the old fan markers used?
The fan markers were used to indicate which radio range course they were located on by the use of morse code.

What is the difference between "bone" and "fan" markers?
I believe fan refereed to the vertical beam shape. Bone was used to describe one of the two horizontal shapes that various fan marker antennas would produce.
The standard type, often illustrated by a cigar shaped chart symbol, had an elliptical or oval-shaped horizontal beam pattern.
The bone type had a bone or dumbbell horizontal beam shape. At the "handle" it was about 3 miles wide at 1000 ft agl. This was preferred at locations used for timed approaches.
My suggested conclusion: The bone marker is also a fan marker.

What about "Z"-markers?
They transmitted a cone shaped signal used to mark the center of the four course range stations to help flywithastick's uncle(as described above) and my old instructor to fly through the cone of confusion. They were also used in association with the enroute NDBs when they were introduced.

Unlike the low-powered ILS Marker Beacons with less than 3 watts the old beacons could be up to 100 watts.