TOP BAND AERIALS
A QUICK NOTE
I'm usually on top band in the evenings along with some locals here in Worthing, Sussex. We hang around 1980kHz so, if you hear us, give us a shout.
One-sixty metres is a brilliant band. It's usually very quiet, there's plenty of room, and it can be good for DX as well as inter-G. So, why is it underpopulated? Basically, people don't use top band because of the sheer length of the aerial needed to put out a decent signal. It amazes me to hear people saying that an aerial loads up and the SWR is one to one - so it's great. A decent AMU will load up a six inch nail, but it's going to be a pretty naff aerial.
I've now lengthened my top band aerial from 130 feet to almost 200 feet. The reason being that the first 30 odd feet of the wire was in the shack and running through the loft. That's the first 30 feet where the current is high, and maximum radiation takes place. I now have about 70 feet of wire thrown around the loft and 130 feet outside in the open. What this has done is push the current along the wire and out into the garden. Rather than current fed, it's now moving towards voltage fed. This change necessitated a slight mod to the matching unit below. A right bodge, but it worked!
AN EXTRA COIL LASHED ONTO THE AMU - PERFECTION!
THE G4NSJ DUAL LF BAND AERIAL
I then had a thought. A half wave horizontal aerial for eighty metres and a three eighth wave aerial for top band? From one piece of wire? Below, is the diagram of the G4NSJ dual LF band aerial. Take a look at the diagram. An end-fed (Zepp) half wave on 80 and an end-fed three eighth wave on 160... Think about it.
One top band, the feeder is joined together at the shack and and the aerial becomes a three eight wave end-fed on 160 metres.
This is very simple, and very effective.
EXCELLENT REPORTS ON TOP BAND FROM STATIONS 300 MILES AWAY?
You might think that this statement sounds crazy, and you'd be right if we were talking about a horizontal aerial. My inverted L isn't giving me very good signal reports from around the UK. Why? Because the vertical section is fifty feet long.