VOR confusion preparing for test

If ATC asks you for a radial off a VOR, you need to know to give FROM radial. Likewise, ATC instructions always are based off FROM radials.

A TO radial is the 180 degree reciprical of a FROM radial. The TO radial idea is useful to pilots, because pilots wanted to be able to have the same number in the VOR head as in the DG. So they invented TO radials.

The reason FROM radials are the default, is the way we learned angles. Angles always eminate from a point and go out in space as in a triangle. Unfortunately the adoption of TO radials puts some ambiguity in the discussion, because now we have a radial that has two different names, one 180 degrees off the other. Its not too bad once you understand it, but its not trivial either.

Learn radials based on where the plane icon is in relation to the QUADRANTS. Then you will really understand it. And remember, the direction the plane is facing doesnt change the VOR head. You can take and turn the plane 180 degrees in space and the VOR wont change. Keep that one in mind. Work all the VOR problems in the instrument test questions.
 
Funnily enough, when I started IR flying is when I found out the LOC didn't care about tuning. It will show you your relation to the signal, no matter what heading you have in. So, you actually never need to put the Final Approach Course in. Most of us do anyway, just as a reminder.

Prior to that I thought a LOC was just a fancy VOR radial, but it's not. :loco:
 
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coloradobluesky said:
If ATC asks you for a radial off a VOR, you need to know to give FROM radial. Likewise, ATC instructions always are based off FROM radials.

A TO radial is the 180 degree reciprical of a FROM radial. The TO radial idea is useful to pilots, because pilots wanted to be able to have the same number in the VOR head as in the DG. So they invented TO radials.
Click to expand...

You should have quit while you were ahead. :mad2:
 
coloradobluesky said:
If ATC asks you for a radial off a VOR, you need to know to give FROM radial. Likewise, ATC instructions always are based off FROM radials.

A TO radial is the 180 degree reciprical of a FROM radial. The TO radial idea is useful to pilots, because pilots wanted to be able to have the same number in the VOR head as in the DG. So they invented TO radials.
Click to expand...

Never heard of a "TO radial"*.

Since a radial is a line of magnetic bearing FROM a VOR, "FROM radial" is redundant. And "TO radial" seems unnecessarily confusing.

Maybe I just missed "TO radial" over my career. Can you point me to an official source that uses that terminology?


*Certainly with ADF, one refers to bearings to and from a station, but those are not typically referred to as radials.
 
Rather than deny they exist, I simply understand what they are. The reason they exist is as I stated. I admit they cause confusion.

I took a course in statics. The course should have been named vectors. You can draw the vector pointing EITHER direction, so long as all the other vectors agree with your initial convention. Solve the problem. Now draw all the vectors in reverse directon, you get the same answer. Its like arguing which way is UP. If you choose the wrong way, but all the others are wrong to, youll get the right answer. There is a theorem explaining this in excruciating detail in a type of math called Topology. But it is so basic to Geometry that Im not even going to get into it. Its something we all had in junior high, high school etc when we learned about triangles. If you dont understand it by now, you never will.... I suspect you understand it, you just choose to DENY it. You do know how to subtract 180 degrees from an angle, correct? Thats all it is.

TO angle = FROM angle - 180 degrees. It is a definition. Now deny it. Puff yourself up a bit. Impress us. Get hung up about it. Tell your airline interviewer you dont believe in them. Jeppesen uses them, the FAA uses them. All pilots learn about them. Dont blame it on me, I didnt invent them, I just choose to understand them.
 
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I think you're confused colorado.

Radials are FROM only. There is no TO. Not only would that confuse the heck out of a pilot to figure out on the fly, how would the VOR device in the plane itself know what to read?

If I'm southwest of a VOR, the only radials that actually come from the VOR are southwest radials. Period, that's it, no more complex then that. Try as I might I will never receive a northeast radial because it doesn't exist from where I am. Sure I can turn the OBS knob, I can turn the plane around, but it doesn't change what is coming from the VOR.

This has nothing to do with angles, vectors or headers. Yes, angles, vectors or headers can change, but the mechanics of a VOR are pretty simple.

A VOR ground station sends out an omnidirectional master signal, and a highly directional second signal is propagated by a phased antenna array and rotates clockwise in space 30 times a second. This signal is timed so that its phase (compared to the master) varies as the secondary signal rotates, and this phase difference is the same as the angular direction of the 'spinning' signal, (so that when the signal is being sent 90 degrees clockwise from north, the signal is 90 degrees out of phase with the master). By comparing the phase of the secondary signal with the master, the angle (bearing) to the aircraft from the station can be determined. This line of position is called the "radial" from the VOR.
 
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Not sure I understand where Colorado's vitriol came from.

Here's how the FAA defines a radial in the PHAK:

"The course or radials projected from the station are referenced to magnetic north. Therefore, a radial is defined as a line of magnetic bearing extending outward from the VOR station."

(Bolded mine)

That's what I learned. That's what I taught. "TO radial" still sounds self-contradictory to me, and I would not allow a student use that terminology.

But Colorado seems to like it, so by all means he can keep using "TO radials" and confusing students and fellow pilots.

In any case, pretty sure I'm done debating it.
 
Caramon13 said:
I think you're confused colorado.

Radials are FROM only. There is no TO. Not only would that confuse the heck out of a pilot to figure out on the fly, how would the VOR device in the plane itself know what to read?

If I'm southwest of a VOR, the only radials that actually come from the VOR are southwest radials. Period, that's it, no more complex then that. Try as I might I will never receive a northeast radial because it doesn't exist from where I am. Sure I can turn the OBS knob, I can turn the plane around, but it doesn't change what is coming from the VOR.

This has nothing to do with angles, vectors or headers. Yes, angles, vectors or headers can change, but the mechanics of a VOR are pretty simple.

A VOR ground station sends out an omnidirectional master signal, and a highly directional second signal is propagated by a phased antenna array and rotates clockwise in space 30 times a second. This signal is timed so that its phase (compared to the master) varies as the secondary signal rotates, and this phase difference is the same as the angular direction of the 'spinning' signal, (so that when the signal is being sent 90 degrees clockwise from north, the signal is 90 degrees out of phase with the master). By comparing the phase of the secondary signal with the master, the angle (bearing) to the aircraft from the station can be determined. This line of position is called the "radial" from the VOR.
Click to expand...


If what you're saying is true, then why can you tune 210 from the NE and fly 'to' the station and pick up that radial(which we all agree is on the other side)after you pass. How can we argue about how the instrument behaves? It does what it does right?

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FYI student pilot here, I haven't had to use these yet. I like tangowhiskeys posts. Its confusing to me why people are arguing whether the radial exists on the other side or not when it doesn't really matter, if you can tune to it and realize that it is on the other side based on the TO indication. Doesn't it depend on the problem you're trying to solve?, do I want to know where I am in relation to the VOR(use FROM), or do I want to track a certain direction relative to the VOR(use either TO or FROM).
 
jimbilly said:
If what you're saying is true, then why can you tune 210 from the NE and fly 'to' the station and pick up that radial(which we all agree is on the other side)after you pass. How can we argue about how the instrument behaves? It does what it does right?

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FYI student pilot here, I haven't had to use these yet. I like tangowhiskeys posts. Its confusing to me why people are arguing whether the radial exists on the other side or not when it doesn't really matter, if you can tune to it and realize that it is on the other side based on the TO indication. Doesn't it depend on the problem you're trying to solve?, do I want to know where I am in relation to the VOR(use FROM), or do I want to track a certain direction relative to the VOR(use either TO or FROM).
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The answer to your first question is that you can tune whatever you want, you will never be on the 210 radial if you are NE of the station. It just doesn't exist there.

I'm not arguing if the radial exists on the other side, it does, you just can't use it because radials by their very nature are FROM the VOR, they radiate outwards clockwise. But that's the point, it exists ON the other side, not on the side you're on.

If you are NE of the station on the 030 radial inbound to the station flying a heading of 210 after station passage you will be on the 210 radial outbound from the station. Don't confuse TO/FROM on the VOR with inbound/outbound, they aren't the same thing. The TO/FROM just help you identify your position, not where you're going.

You can fly a radial inbound or outbound, but the radial doesn't change in either case.

TangoWhiskey's last post of the cone I described with the deflection is perfect for understanding how you can identify where you are without ever even touching the OBS knob just by using the TO/FROM indicator and the needle deflection.

Think of it another way, I'm flying a heading of 210 I'm southwest of the station on the 210 radial. The needle is centered and 210 is at the top of the VOR.

If I turn the OBS knob so 030 is at the top of the VOR instead of 210, that doesn't mean I'm now on the 030 radial. I'm still flying on a 210 heading outbound on the 210 radial. And..even if I turned around 180 degrees, I'm STILL on the 210 radial, though I'm inbound, again until I pass the station then I'm back outbound on the 030 radial.

I had a really hard time with VOR's but seriously if none of this is making sense just PM me, happy to talk about this offline or on the phone w/e.
 
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Nope, there are no "To" radials. Radials are the names assigned to outbound bearings from the station. The reciprocal radial on the other side has a different name.
 
Thanks Caramon, I'm pretty sure I get it though. The TO/FROM only really makes sense (to me) IF you are flying the heading of the radial in question.

What radial am I on/crossing? Find the radial FROM the station that centers the needle.

Fly that heading to track FROM the station, away.

Fly the reciprocal to fly TO the station. FROM would still be indicated unless you change the OBS to track the outbound radial(reciprocal) TO the station, then FROM as you pass over and away. Clear as mud.:D
 
The problem with defining "to" radials gets real obvious when you start instrument training.

Cessna 123XY hold southwest of PXN VOR on the 200 radial left turns

There is no TO radial, and if you used one in that instance, you would leave protected airspace and risk banging into something.
 
Tell me if I have this right.

I read somewhere that "radials" going to the station are called bearings. And "radials" coming from the station are called radials.

Lets say that I'm flying a heading of 090. The VOR is directly east of my position.

So I'm flying the 090 bearing to the station. At the same time, I'm flying 270 radial to the station?


Once I pass the VOR, I'm now flying 90 radial from the station. And at the same time the 270 bearing from the station?

Thanks.
 
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orange said:
Tell me if I have this right.

I read somewhere that "radials" going to the station are called bearings. And "radials" coming from the station are called radials.

Lets say that I'm flying a heading of 090. The VOR is directly east of my position.

So I'm flying the 090 bearing to the station. At the same time, I'm flying 270 radial to the station?


Once I pass the VOR, I'm now flying 270 radial from the station. And at the same time the 090 bearing from the station?

Thanks.
Click to expand...

Close. After you pass the station going eastbound, you're on the 090 radial and the bearing the station is 270.
 
coloradobluesky said:
If ATC asks you for a radial off a VOR, you need to know to give FROM radial. Likewise, ATC instructions always are based off FROM radials.

A TO radial is the 180 degree reciprical of a FROM radial. The TO radial idea is useful to pilots, because pilots wanted to be able to have the same number in the VOR head as in the DG. So they invented TO radials.

The reason FROM radials are the default, is the way we learned angles. Angles always eminate from a point and go out in space as in a triangle. Unfortunately the adoption of TO radials puts some ambiguity in the discussion, because now we have a radial that has two different names, one 180 degrees off the other. Its not too bad once you understand it, but its not trivial either.

Learn radials based on where the plane icon is in relation to the QUADRANTS. Then you will really understand it. And remember, the direction the plane is facing doesnt change the VOR head. You can take and turn the plane 180 degrees in space and the VOR wont change. Keep that one in mind. Work all the VOR problems in the instrument test questions.
Click to expand...

IMHO there is no such thing as a TO radial, because radial means FROM. Check the Pilot/Controller Glossary. If you are roughly northeast of the facility you can be outbound on the 030 radial or inbound on the 030 radial (or crossing, or intercepting....you are still northeast). It is a statement of position, nothing more.

Let's say that you are on I-70, driving east from Denver. You suddenly remember that you forgot to put the cat out and do a 180 at the next exit. Now what freeway are you on?

Bob Gardner
 
orange said:
Tell me if I have this right.

I read somewhere that "radials" going to the station are called bearings.
Click to expand...

I'd say not necessarily.

From what I recall teaching about NDB's, a bearing can either be TO or FROM a station, and for clarity that should always be specified.

For instance...

plan_view_miv_520.gif


Outbound to the NW, it would be proper to say you were tracking outbound on the 327° bearing FROM the station. Turn around, and you'd be inbound on the 147° bearing TO the station.

With VOR's, radials are always FROM. If that was a VOR in the above diagram, you would say you were on the 327° radial whether inbound or outbound NW of the station, until you got to the VOR. If you continued straight after station passage, you'd then be outbound on the 147° radial.

Does that help?
 
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In summary, a bearing relative to a station can be either to it or from it, but a radial is always a bearing from a station by definition.
 
Palmpilot said:
In summary, a bearing relative to a station can be either to it or from it, but a radial is always a bearing from a station by definition.
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More to the point, a bearing is just a direction of one object from another. It's a generic term. For instance, I report smoke plumes with bearing and range (and a landmark if I can). ELTs with a bearing. The usual traffic calls are rough relative bearings (e.g. 10 o'clock).

A radial is a phase difference between two radio signals, and is quite specific. The reference is always the station, because that's where the two radio signals are generated.
 
Radials radiate...

I always thought that they're called "radials" because they RADIATE outward from the VOR source, like rays of light.
 
Pre-solo student pilot here. Thank you all for this discussion. I learned a lot reading this thread and feel I have a much better understanding of VORs.
 
And probably a better understanding of the nit-picky nature of pilots, too! :)
 
bobmrg said:
IMHO there is no such thing as a TO radial, because radial means FROM. Check the Pilot/Controller Glossary. If you are roughly northeast of the facility you can be outbound on the 030 radial or inbound on the 030 radial (or crossing, or intercepting....you are still northeast). It is a statement of position, nothing more.

Let's say that you are on I-70, driving east from Denver. You suddenly remember that you forgot to put the cat out and do a 180 at the next exit. Now what freeway are you on?

Bob Gardner
Click to expand...

The biggest question here, is why you turned around for a cat... :)

But that is actually a great example for students, and I may just use that in the future..
 
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