M0CVO 9:1 UNUN -£35.79 PLUS £2.95 CARRIAGE
This is a 9:1 UNUN. It provides a transformer for the feedpoint of a long wire radiating element and converts the impedance from 450Ω (+/-) to something nearer to the 50Ω expected by your transceiver. There are three connections on the UNUN, a SO239 to which you connect the coaxial feed line and two machine screws with butterfly wing nuts. To one of these you should connect the longest piece of wire you have available and to the other you should connect a length of wire to earth. This is a necessary connection as it will reduce static pick up and provide a direct path to earth for any possible lightning strike or build up of static in the air. The best way to do this is to attach a length of wire to a ground rod and fix it to the UNUN at this terminal. correctly. Fix the feedpoint up as high as you possibly can – it may be attached to a pole or to a wall and then attach the other end of the wire to a point as far away as is possible. This is best done if the wire can be kept in a straight line and horizontal but, if this is not possible due to space restrictions, do not despair. The wire may be dog-legged, sloped or fixed in any number of ways to enable it to fit in the space available.
The other end of your coaxial cable should be attached to your ATU and then from the ATU to your transceiver. Power up, make final adjustments to tune and away you go.
Maximum power is 400W CW or 500W PEP.
A well made unit made in the UK better quality than some other cheaper and inferior quality items available originating fr