G3VjV Pedestrian Portable
Mini Loop MK III
This is the latest version, covering all HF bands except 60 metres & 30 metres,
this is 35 cm diameter made from 16mm Aluminum tube.
The matching for 1.8 to 52 MHz is just by adjusting the length of the
apex X by sliding a cable tie up or down.
There are four Tuning Modules:
A : 160 metres: This covers all of Top Band in four sections.
B : Lower HF: This covers a small section of 160 m, the Phone section of 80 m and 7.0 to 7.2 MHz.
C : Upper HF: This covers 20 m, 17 m, 15 m, 12 m and 10 m.
D : Six metres.
( more to follow )
Mini Loop MK I
160 m Portable Set-up, FT290 with Top Band Transverter, max power 7 watt.
50 cm diameter loop antenna for Pedestrian Mobile use.
The Transverter is an old Microwave Modules 2m - 10m unit, I have converted it to 160m, the main circuit board fits into
the FT290 Battery compartment, the P.A. is in the "Outrigger" Box.
Loop Diameter : 50 cm, Fixed Capacitors 4700 pf for 1.83 - 1.9 MHz, 4230 pf for 1.9 - 2.01 MHz plus 9 - 750 pf Jackson Dilecon variable capacitor.
The loop is made from 1.6 metres of RG213, this can be unclipped from the horizontal bar for easy transport.
Power-Pack : 13.2 v, 2500 ma h.
Tested range : (at this time) 5 miles SSB, 150 miles CW.
The inset shows the Clip-On Tuning Indicator, this is a basic R.F. Ammeter circuit driving an LED and meter.
Close-up of the Tuning Unit.
Mini Loop MK II
This is a smaller and less efficient Antenna but a little easier to carry.
It is 35cm in diameter and covers 160m and 80m, I have had one contact with this
Antenna so far, I could be heard in South Wales with some difficulty using 5 watts of SSB in daylight
hours, a distance of 158 miles, 254 km.
The Loop is constructed from two 1.1 metre lengths of Aluminum sheathed Co-ax in parallel,
the diameter of each conductor is about 8mm.