by Greg Whiter, VK
4IG (Ex VK3CA) 

These pages depict Clark Masts original range of mast products.
To see Clark's current mast series go to Portable Mast Australia Pty Ltd's (PMA's) web site.


Page 9 of 18 - Clark Masts, over 67 Years Old in 2023 - Type 63/70 Trailer Mast
In the early 1970's Clark Masts published their first catalogue in 16 years. Alec Clark, the company's founder had been designing and building portable air-operated telescopic masts since 1957. During this time Alec Clark's unique lightweight portable masts had found their way into applications throughout the world with government Departments Of Defence, Police Departments, Fire Departments and Emergency Services. Commercial and industrial applications included for Radio Field Strength Surveying, TV Field Strength Surveying and portable radio communications. 

Alec Clark's company, Clark Masts Limited, performed practically ever manufacturing operation itself in-house. Fabrication, casting, precision machining, canvas sewing, plastic and rubber mouldings, anodising and plating, painting, printing, publishing and even the manufacture of packing cases were all in-house operations. 

Australian users first saw these unique portable masts in the early 1960's courtesy of a antenna manufacturing company called Belling-Lee and the foresight of a gentleman working for them at the time, Frank Welsh. Frank went on, with others, to form his own company, Scalar Industries, in the late 1960's and brought the Clark Masts agency with him. Following Frank Welsh's retirement from Scalar in the mid 1980's
GFS Electronics took on the Australian distributorship and continued to market Clark Masts in the Australia Asia-Pacific region until the company was closed in 2011. In 2012 a new company, started by Greg Whiter, who was previously Managing Director of GFS Electronics took over the Australian distributorship of Clark Masts. That new company is Portable Masts Australia Pty Ltd.

Illustrated in this web page, for historical purposes, is the 21 Metre Type 63/70 Trailer Mounted Mast page from Clark Masts early 1970's catalogue. Today's equivalent to the model 63/70 is the Model


Type 63/70 Trailer Mast - Clark MastsClark Masts 21 metre Type 63/70 Trailer Mast

The Clark Masts Type 63/70 Trailer Mounted mast of the late 1960's - early 1970's was designed to lift heavy duty loads, using a 21 metre, 40Kg headload rated WT6 mast. The 63/70 was particularly designed to work with portable communications centres for emergency services and the like, where the mast's 40Kg headload capability could support quite a number of UHF, VHF and HF antennas simultaneously. Like all other WT Series masts the 63/70 Trailer Mast's mast sections were keyed to prevent inter-section rotation, making it suitable for use with directional headloads. The 63/70's extended height of 21 metres was obtained using 7 sections which also provided a retracted height of 3.91 metres. Being a WT Series mast, the 63/70 Trailer Mast's base tube diameter was 152 mm (6"). A petrol operated Compressor/Mast Controller was incorporated for mast extension/retraction and the mast was lifted into the vertical by a hand cranked screw jack.

Type 63/70 Trailer MastClarkMasts Type 63/70, 21 metre Trailer Mast Specifications

The Clark Masts type 63/70 Trailer Mast was supplied with all the components necessary for it's deployment.  These included Guy Assemblies, Guy Stakes, Guy Stake Hammer, Guy Stake Location Line, Base Plate, Base Plate Spikes, Mast, Weather Cover and screw jack Crank Handle. These deployment accessories were stored in a steel tool box fitted to the trailer frame.   

A deployed 63/70 Trailer Mast had a wind speed rating, with 1000 square cm sail area on top into wind, of 48 km/hr un-guyed and 112 km/hr when guyed. The specified time taken to extend the mast using it's petrol compressor was 5.5 minutes.

- A slight diversion from portable mast manufacturing occurred for Alec Clark in 1967 with the design and manufacture of a small moped called the Clark "Scamp". The Scamp was developed and marketed in the United Kingdom by Alec's company AN Clark (Engineers) Limited from March to November 1968. For more details on the Clark Scamp moped see HERE.

Next Page - Clark Masts History - Page 10 - 63/100 Trailer Mast

Other Web Articles by the same author   EARLY YAESU MUSEN EQUIPMENT IN AUSTRALIA 


Links to other pages in this article
Page 1 Clark Masts History - Early 1970's QT Mast Series
Page 2 Clark Masts History - Early 1970's ST Mast Series
Page 3 Clark Masts History - Early 1970's PT Mast Series
Page 4 Clark Masts History - Early 1970's WT Mast Series
Page 5 Clark Masts History - Early 1970's DAF Mast Series
Page 6 Clark Masts History - Early 1970's SCAM Mast Series
Page 7 Clark Masts History - Early 1970's PB1 Mast
Page 8 Clark Masts History - Early 1970's Surveyor Mast Series
Page 9 Clark Masts History - Early 1970's 63/70 Trailer Mounted Mast
Page 10 Clark Masts History - Early 1970's 63/100 Trailer Mounted Mast
Page 11 Clark Masts History - Early 1970's Mast Fitting and Mountings
Page 12 Clark Masts History - Early 1970's Vehicle Mounting Accessories
Page 13 Clark Masts History - Early 1970's Air Supply Equipment
Page 14 Clark Masts History - Early 1970's Guying Equipment
Page 15 Clark Masts History - Early 1970's Antenna Fittings
Page 16 Clark Masts History - Early 1970's Miscellaneous Equipment
Page 17 Clark Masts History - Early 1970's Antenna Mounting
Page 18 Clark Masts History - Early 1970's Useful Wind Information
Appendix Clark Masts History - The 1968 Clark Scamp Moped

Any comments on this article should be directed to the author, Greg Whiter at: 


Details On Clark Masts Current Range Of Portable Telescopic Pneumatic Mast Products 

This page is sponsored by Portable Masts Australia Pty Ltd
Suppliers of Fast Erecting air operated telescopic portable masts and towers as well as Debeglass Non-Conductive Guy Wire
For product details and a catalogue covering over 200 different mast types of Clark Masts go to
PMA's web site.
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Phone: +61 402130692
Mob: 0402130692
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Copyright © Greg D. Whiter 2023 - All rights Reserved

This page was last updated 05-01-2023

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