The photos are rather large and may take some time to load.
The mast consists of 4 painted steel sections, from the first rotatable mast we installed in 1977. The mast has a width of 480 mm (1.57 ft) center to center of the frame legs. The mast has been re-painted before re-erected.
The use of the mast is to chase multipliers and for this we have 6 x 4-el yagis - 2 each on on 14, 21 and 28 MHz. They are fixed, pointing to Europe (170o) and the USA and West Indies (290o). At the top are three rotating antennas installed, a Fritzel FB 505 yagi as well as a15-el VHF and a 23-el UHF yagi.
From the top are one slooping dipole for 7 MHz and one inverted dipole for 3.5 MHz installed.
Two SixPaks are fitted to the mast where one fits all monoband yagis and the other fits the FB 505, 9-band vertical and the wire antennas. Refer to the antenna switching page.
The link antenna for the Local Radio Access Net (WLAN) is also fitted at the top of the mast.
The height of the mast is 24 m (79 ft) above ground including the foundation. The guying radii is 10 m (33 ft). The mast is guyed in one level using 2 tons Parafil synthetic rope from the top to about 5 m above ground. The reason for synthetic rope is to prevent the guys from distorting the pattern of the yagis.
The steel wire from about 5 m height to the guy anchors serves two purposes. One is to ease the tightening of the guys. The second purpose is that the synthetic wire is subject to being damaged by fire. To safe guard the guys from grass fire it is evident that steel wire should be used at the lower part of the guy wires.
As with the other masts we have installed a fall guard wire system used when climbing the mast. The same clip can be used on all the masts. This is a precaution need on all masts but seldom used on ham masts!
Below are some more photos:
Installation of the 15-el for 144 MHz.
Installation of the top 4-el for 28 MHz.
The antennas above the guy wires are ready for use.
The SixPak for 14, 21 and 28 MHz is fed with 7/8" feeders. The other one uses RG 213 and connects the dipoles, the FB 505 and the HF9V 9-band vertical.
Mast 4 as seen from the 36m level of Mast 1
The HF9V 9-band vertical is fitted on the ground about 15 m from Mast 4.