G4NSJ – Passive repeaters VHF UHF Yagi antenna aerial


I’m in Worthing, West Sussex. Picture this… 10 ele 70cms Yagi on the roof of the house aimed at the Isle of Wight repeater, GB3IW. In the shack, the coax is connected to my TYT handheld, great signals both ways.

Now, unplug the coax and fit the rubber duck aerial to the hand held. Nothing from the Isle of Wight. Fit a half wave dipole to the end of the coax from the roof Yagi and place it near to the hand held. Good signals from and to the Isle of Wight. For my next trick, I’m going to place a 70cms Yagi in the shack aimed at the middle of the room. What’s the point? I should be able to walk around the shack, using the rubber duck on the hand held, and chat through GB3IW.

This set up is called a passive repeater. The idea of a passive repeater is, for example, to fire signals down into a valley where there would otherwise be no signal. A beam atop the hill aimed at the transmitter connected to another beam aimed down into the valley. This works and is used commercially.

OK, how about this… your favourite repeater is too far away for you to use a hand held with its rubber duck. Install a Yagi atop a pole in the garden aimed at the repeater. Install another Yagi on the pole aimed at the house. Connect the two beams with coax. You should be able to use the hand held in the house. Is this going to work? I’ll let you know in the spring when the weather is nicer.

The Yagi aimed at the distant transmitter needs to be high gain so a strong signal is sent to the second Yagi. I’ve read various articles online where this has worked well where there is no or very little signal inside a building, rendering hand helds useless. In one case, a dipole was placed in the basement, fed from an aerial on the roof of the house, giving enough signal for a hand held to be used.

You don’t need a licence, an NOV, or permission… and several people can work through the repeater at the same time as long as they’re on different frequencies within the band. Desensing permitting.

Here’s a great article by Iain Young, G7III

I’m working on this page. More coming soon…