where does "QNH" come from?
 

Okay, okay who wants to be the first to say 'ATIS'(or whatever your local is).
I know it's probably a stupid question but whats the origin of the word/acronym?

:confused:

Apparently 'Q' codes come from the days of morse code, where the use of standard questions helped to cut down message length. 'Q' therefore stands for question.

Example, 'QDM' would get you a magnetic bearing to a station, QTR would get you the correct time, etc.

QNH stands for what would my altimeter be reading if I were on your airfield above MSL, or the barometric pressure setting at that airfield.

Hope this helps.

Kermie

[ 07 August 2001: Message edited by: Kermit 180 ]

There are probably others on this forum that can answer this question more thoroughly than I can, but still:

The "Q-codes" were originally a whole bunch of three letter codes, starting with Q. This was sort of a "short hand" from the time when morse codes were used to transmit messages. There were LOTS of Q-codes, which all had a different meaning. QNH being one of them, meaning barometric pressure expressed in hPa, corrected for the altitude of the measuring point.

The Q is to destinguish these special three letter codes from other three letter words, since very few (three letter)words start with Q. (Any at all?) (Yes, Quo. ;))

The other two letters? -Don't know if there's any system there at all. And that might even be the point.

Other Q-codes: QDM, QDR, QFE, QTE and QPR. ;)

Nick.

GWTF
Its not an acronym - just an abbreviation to make Morse transmission easier.
Kermie
Nearly right - The 'Q' code is not, in itself interrogative. To make it into a question rather than a statement it is suffixed by IMI, those three letters being sent as one continuous character (in Morse 'speak', IMI barred)
Without the IMI. it is just a statement i.e. 'the Altimeter setting which will indicate airfield height above sea level' much simpler as QNH :D :D

I understood it was “Question Nautical Height” and “Question Field Elevation”.
Is this incorrect?

Yes they are still, or were until very recently, in use with the military. I learnt morse and various Q & Z codes during my Army signals training. I belive they no longer teach it unless it is required for a specific job.

Essentially the Q and Z codes where 3 letters which correspond to specific sentences or meanings. 3 letters are much easier to send than the full sentence. It therefore goes on that QNH/QFE was used by the RAF when the radio operators used morse and not voice. BT (those in the know will know :D )

Q codes are still used by radio hams, although the requirement to know morse code is being downgraded and will probably vanish over the next few years and thus the Q codes will most likely fade away too. (But this brings us into the world of ham radio politics, which is frighteningly unpleasant).

QRZ? de G6HVY

Wags will tell you QNH stands for "Queer Notation of Height".

Questioning Never Hurts...

Talking about QNH, QNE, QFE...

I did my basic training in the States and when I came back to Europe I was really astonished by the fact how our authorities are dealing with simple stuff (in the states it was simple) :confused: :confused: . Standard (QNE) setting only above FL180, so all the G/A-guys don't have to worry about transition alt/level!

Can anyone explain why we don't do it the same way here in Europe? :rolleyes:

Who is using QFE (apart from maybe some aerobatic pilots)? :confused:

QNH "Normal Home"

QNE "Normal Enroute"

QFE "Field Elevation"

Moscow uses QFE. Thanks to the Jepp plates, it's not as difficult as it could be.

A Spam mate doing an exchange tour here told us that they consider 'QFE' stands for 'Queer F*cking English'!!

Akro: I fly Turbo-Prop, in Europe and we often fly pretty long sectors below FL180. (Especially when there's strong headwind.) Wouldn't you have to change QNH "all the time" to make sure you have the same reference as other traffic if the TA is 18 000 ft?

Nick.

I too thought that anything prefixed with Q meant question. I have since been told that the Q is Latin for Quasi, meaning 'about'.
ie QNH = quasi nil height, about nil height.

He was a wise old man, so I kind of believed him...... he could also be wrong.

Quod Erat Demonstrandum??? ;)

Thanks all.

For the bored or interested, officially, they are contained in Appendix 9 to the Radio Regulations Annex to the International Telecommunications Convention (Atlantic City) 1947, for blocks QRA to QUZ inclusive, and in ICAO publications Dec 6100-COM/504/1 for blocks QAA to QNZ inclusive.

Radio hams could probably tell you a lot more about them, but there are a few interesting ones, like "QUQ - Shall I train my searchlight nearly vertical on a cloud, occulting if possible and, if your aircraft is seen, deflect the beam upwind and on the water (or land) to facilitate your landing?" :D

Hi Nick F.,

Of course you would have to change alt setting from time to time (not really all the time, depends on the weather as well)! However, as we were flying under so called "flight following" all the time (another neat service you get from ATC in the states as well -> just another huge topic that works much better over there), they always gave us the alt setting for the area we were flying in! When you enter a new sector the new controler automatically gives you the new alt setting.

Who else is using QFE apart from Moscow?
(I heard also that Alitalia is using QFE for their approaches? It might be just a rumour though.)
Any help is appreciated!

Q codes were my downfall when I trained to be a ship's radio officer. There were over three hundred to learn and I'm afraid I gave up :(

I believe they evolved from the Post Office telegraphy two letter codes, when sending Morse code you abbreviate as much as possible. Experienced WT operators would even abbreviate numbers if sending a lot of them ie 1 (.----) would become .- 2 (..---) would become ..- etc. The codes were prefixed by "Q" to make them more obvious, when you heard the letter "Q" you automatically expected a Q code. There have also been Z codes and X codes. All these letters are rarely used in text so they stand out. For most of the codes there is no logic or rationale although it may not be a coincidence that QRS means send more slowly and QRQ means send more quickly. Assigning a "meaning" to the codes just makes them easier to learn. Q has certainly nothing to do with question, a Q code is made into a question by suffixing it with a question mark eg QRL? - are you busy?; QRL - I am busy.

Don

he answer to QNH.
Plenty of people have talked about the origin of 'Q' so I'll go no further. As to 'NH' you need to think about sea level. As QNH give you your height abouve sea level (we call it altitude)we need a reference datum. Mean sea level is taken from a measurement point in Cornwall - Newlyn harbour infact. Therefore the NH is derived from Newlyn Height.