G4ALG's QRP Radio Pages

[ Previously GW4ALG (QRT in February 2007) ]

[ Home ] [ Antennas ] [ Introduction ] [ QRP Operating ] [ Station Equipment ] [ Station Summary ] [ Test Equipment ] [ Links ]

[ Up ] [ Doublet ] [ MFJ-974HB AMU ] [ Open Wire Feeder ] [ Portable Mast ] [ Switched Balun ] [ Wall-mounted Mast ] [ 144 MHz Yagi ] [ 144 MHz 6 element Yagi ] [ 144 & 432 MHz Yagi ] [ 432 MHz 12 element Yagi ] [ 1296 MHz 16 element Yagi ]

Portable Mast

Here is a description of the 4 metre portable mast that I use for supporting VHF antennas.  The mast was made for me by my Dad in about 1971 and has been used to support large VHF antennas, including large Yagi antennas for the 2m and 4m bands.  

Here is a photo of my Dad taken in 1976, with the family car in the background.  (Yes, it's an Austin Cambridge A55 having a steering column gear change.)




This portable mast uses a single 4m length of galvanised steel gas pipe for the pole.  It's a very heavy pole that I've used for portable operations when taking the gear to site by car.    Although heavy, the pole will not bend, and no boom-to-mast clamp is going to crush this material!  But it does need a substantial base to support it.

The mast base is made of mild steel, and comprises a steel pin that has been welded in place on the underside of a 1/4 inch (6.4 mm) steel plate measuring  6  x  6 inches (152  x  152 mm).    A partially-threaded bolt having a long grip length has been mounted in one corner of the plate.

The pole drops over the centre pin, and the clamp is tightened so that the pole will turn under the control of a handle (that is clamped to the pole), but not when the wind blows.

 

Each half of the clamp has been faced with 2.5 mm rubber sheet.  I believe that the rubber was fixed in position using Evo-Stik impact adhesive.  After 53 years, the rubber is still in place!  
 

 

The mast base is hammered into the ground, and two very long coach bolts are driven into the ground through the holes in the base plate to prevent the base rotating.


 

This mast uses a 4-point guying system.  The guy plate is made from 1/8 inch mild steel and rests on an exhaust clamp that is fixed to the pole.  Substantial custom-made guy stakes (made in the early 1980s from mild steel) are now used to support the mast.  The guy ropes are made from 8 mm diameter polypropylene rope secured to the guy plate using D-shackles.. 

 

The following photo shows the turning handle that is made of beech wood and fixed to the pole using an exhaust clamp. 

 

I hope this page provides some ideas if you are contemplating making your own mast for portable operation.   There is plenty of scope for selecting different materials if, for example, a much lighter mast is required.