GMQ-33 Cloud Height Set

© Brooke Clarke 2015



Got this because I already have the TMQ-34 Meteorological Measuring Set and this set is packaged in the same transport case and was also used by the US Air Force.  Part of my general interest in weather.

GMQ-33 Transportable Cloud Height Measuring Set

This is a single box (transportable by one man) solution that used the round trip time of a laser beam to determine cloud height.  The beam needs to be plumb and to accomplish that there's a bubble level on the front panel.  Note that the prior GMQ-13 needed to be installed on concrete pads in surveyed locations and was not at all transportable.

Jan 1989 - AWS began an initiative to acquire an additional 178 AN/TMQ-34 Tactical Meteorological Observation Systems and 218 AN/GMQ-33 Cloud Height Sets in addition to the 401 TMQ-34s and 224 GMQ-33s it already purchased.

10 May 1991 - Operation PRODUCTIVE EFFORT/SEA ANGEL (Wiki). US forces deployed to Bangladesh to provide assistance in the wake of a 30 April cyclone and deadly tornadoes that killed hundreds of thousands of people and leaving thousands more homeless. 1st Wea Wg formed its Crisis Action Team to manage weather support. AFW weather teams deployed with the 1/1 Special Forces Group Disaster Assessment Response Team and 4/25th Aviation Regiment from 25th Infantry Division [Tropic Lightning] to Chittagong. The teams traveled light deploying with 9315TRs [HF fax receiver], TMQ-34 [Meteorological Measuring Set], Belt Weather Kit (USU, Forestry Suppliers), GMQ-33 [Tactical Cloud Height Set], Taylor barometer, and a WRASSE [weather satellite receiver]. GOLDWING [tactical communications set] were not shipped due to cargo constraints. Communication signal reception from High Frequency Broadcast Stations (HFRBS) was very poor and unreliable throughout the entire 30 day deployment period.

IRISNUM= 00874891

Document Detail for IRISNUM= 00874891
IRISNUM    00874891    OLDACC        CLASS    SECRET
END_DATE    02-01-1991    CALL    K178.8912-11    REEL    27748
REL_DATE    04-26-1995    TITLE        TITLE_XT   
ACCNOTES        IRISREF        FRAME    1425
FRAMELST    1578    INDEXID    37    NUMPAGES   
 Includes information on:
TMQ-36 order requirements for Operation Desert Shield (Wiki); TACtical METeorological (TACMET) equipment; expendable supply; supply requirements for desert shield; request for belt kits; additional TMQ-34S equipment; Desert Shield long/term equipment replacement plan; TACMET equipment deployed for Desert Shield; Desert Shield TACMET Fielding plan; Selected TACMETequipment status; Desert Shield TACMET requirements; weather support at Diego Garcia (Wiki); TACMET Scrub; TACMET Doctrine/Concept of operations; GMQ-33 equipment at Diego Garcia; weather support issues and guidance; 3 weather squadron status; new TACMET doctrine; equipment requirements; GMQ-33 requirements; TACMET issues; request for instrumentation ideas; transfer of wind measuring set; policy on TACMET redeployment; air weather service equipment requirements for Desert Shield; TACMET shortfalls; excess TACMET; disk drive demonstration; shipment of D-200 facsimile converter; evaluation of gridcase hard/disk drive requirement; Global Positioning Satellite (PLGR, DAGR) system operations ; equipment shortfalls; TMQ-36 transfer requirement validation; tatical upper air data collection instrument; disposition of GMQ-33 transportable cloud height detector; TACMET attrition assets; TACMET request res[pmse; TACMET maintenance concept; ono/crisis requisition of products for deployed weather operations; and items of interest, such as responses to 5 weather wing/crisis action team action items.

For information on obtaining a copy of the document described above, please click here   
Record provided by: Air Force History

Other Similar Weather Sets


This was the prior model also called a rotating beam ceilometer.  It was a vacuum tube era device that used a light projector that was motorized and a separate detector with a vertical beam.  By knowing the base line distance between the two optical components the right triangle could be solved to get cloud height.

TMQ-34 Meteorological Measuring Set

This is a weather station in a similar type carrying case.  Sensors for wind speed & direction, temperature and barometer with display of these and some derived parameters.

TMQ 36 Tactical Wind Measuring Set

2 March 1989 - Following completion of the AN/TMQ-36 Tactical Wind Measuring Set QOT&E in February, Sacramento ALC granted conditional approval to Vaisala, Inc. for the production of the TMQ-36, subject to the company making a number of design changes.


The FAS web page has some information on the GMQ-33.

Component Parts

A1 System Case

Should Include three adjustable length legs to allow leveling top panel so laser beam goes straight up.  One leg is missing from this set and it's mounting clip is broken off.  The set arrived with the adjusting legs attached upside down on the outside of the transport case instead of mounted inside the lid.

A1A1 Optical Unit

Laser pulse transmitter and receiver.

A1A2 Analog & Remote Card

Includes a DB-37f connector for remote operation.  It's strange they used such a large connector when only a small number of the pins are wired.  There is a dummy automated observing system (AOS) plug to mate with A1A2-J1. Not included with my set.  It's not clear if the AOS plug is needed for manual use.  I expect it's possible to make a single measurement using just the manual trigger button, but with the AOS plug automatic measurements might be made at some predetermined time interval?

A1A3 Signal Processing Unit & Display

Includes Built-In Test Equipment (BITE) function and has system On/Off switch LED display for charging/ready and cloud height in feet, and battery selection switch for Lithium primary battery (BA-5557/U) or Ni-Cad rechargeable battery (BB-557/U).

The display consists of a green LED (charging/ready) and a 4 digit display of feet (0001 to 9999 feet).

There is a modular power supply module that accepts a 24 Volt input, so unlike the TQM-34 that uses 12 volts from it's battery, this unit may wire the batteries for 24 volt operation.

The processor IC is a Z84C00.

A1A4 Battery Assembly

When this panel is pulled out there are two compartments, the top one for the BB-557/U rechargeable Ni-Cad battery and the bottom one for the BA-5557/U primary LI-SO2 battery.
It's not clear how to open the box to install the batteries.  The sliding lid is very stiff, probably because someone left a battery installed that went bad.

There is some type of loose material inside the case, maybe the result of a corroding battery?

For more about the battery see the TMQ-34 battery paragraph.

A1A5 Battery Charger

This is a removable unit that has a standard US AC plug (but can be strapped for either 120 VAC or 220 VAC input and will charge the BB-557/U or may also work for some of the early bb type 5590 family batteries.  It looks like the charger in the TMQ-34 set except it has a plate to allow attaching to the A1A1 transport case.



Heathkit ID-4001 -
IR Cloud Sensor -
Oregon Scientific BAR122HGLA
La Crosse S84107 Wireless Forecast Station
Campbell Stokes Sunshine Recorder - Casella CEL - Wiki -
CCRadio 2E has a weather band
Eppley (Model 2)  Precision Pyranometer, Model PSP covers 285 to 2800 nanometers.
Kestrel 5500FW Fire Weather instrument - very sensitive wind speed and direction, better than any others I have.
SkyScan Severe Thunderstorm Detector
Peet Brothers Ultimeter 2100 Weather Station
Pilot Baloon (Pibal) theodolites - to follow weather balloons.
Radiosonde (Wiki) -
TMQ-34 Meteorological Measuring Set -
Wallace & Tiernan FA 181 Altimeter


2277692 Measuring cloud height and thickness, Francis W Dunmore, Dept of Commerce,  1942-03-31, - radiosonde with photocell lifted by balloon
2390739 System and apparatus for measuring cloud height and thickness, Scherbatskoy Serge Alexander, 1945-12-11, - aircrdaft flying above clouds drops radiosonde throught clouds
3556657 Laser rangefinder, Fred W Quelle Jr, 1971-01-19, - eye safe below 0.3 and above 1.4 micron wavelength. This operates around 1.5 microns.
3741655 Means for determining the existence of an object within a predetermined range interval, B Ling, A Persson, Qualimetrics, 1973-06-26, - pulse reflection
3781552 Self-calibrating multiple field of view telescope for remote atmospheric electromagnetic probing and data acquisition, K Kadrmas, 1973-12-25, - LIDAR (Wiki)
3963347 Erbium laser ceilometer, Joseph Pipo Segre, Norman R. Truscott, American Optical, 1976-06-15, -
4121889 Cloud altitude measuring means, Sven-Erik Soderstrom, Qualimetrics, 1978-10-24, -
4289397 Laser ceilometer signal processing means, Irving Itzkan, Herbert P. Kent, Michael E. Mack, Richard G. Morton, Avco, 1981-09-15, - narrow beam laser transmitter at an angle, wide beam photo receiver pointing straight up.



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