THE PERIODIC NEWSLETTER OF THE CENTRAL COAST AMATEUR RADIO CLUB
ISSUE No 17-01 3rd February 2017
In this Issue:
- Coming Events
- The WIA Fact Sheets
- An unusual stealth aerial only feet above the ground
- Broke & fixed
1. Coming Events
Saturday 4th February at 1300 hours will be the CCARC Business Meeting.
Following will be the Wyong Field Day Meeting.
2. The WIA Fact Sheets
Some WIA members noting accusations and criticisms on social media and elsewhere, have sought a response from the WIA Board to those claims.
In answer to the WIA membership, the WIA Board has issued a series of Fact Sheets to give all WIA members the relevant facts and explanations.
The downloadable Fact Sheets respond to some of the issues already raised, and more may be added later.
The Fact Sheets are accessed via the right-hand side navigation panel of the WIA website, or via the following Link
Source: Wireless Institute of Australia
3. An unusual stealth aerial only feet above the ground
Ham radio is without doubt a great hobby to get interested in, however I hear many say that aerials and their location is a big problem because of their small gardens or local planning rules. Don’t worry too much about placing your aerial high in the sky, you can still put out a signal on the high frequency bands which allows you to be heard.
Have you ever wondered how well an aerial works when only a few feet off the ground, you may be surprised to learn that it works very well indeed and large portions of your country can be worked with this type of arrangement it’s called a near vertical incident sky wave, you may be surprised to learn that 300 to 400 miles can be successfully covered with an N.V.I.S. aerial, (Near Incident Vertical Sky-wave) when placed only one twentieth above ground level.
A forty metre dipole measuring about 66 foot and fed in the middle like a conventional dipole works very well and is virtually undetectable, the signal from the aerial is transmitted straight up to the ionosphere where it is reflected back to earth where it can cover many hundreds of miles.
Running an additional earth wire slightly longer under the dipole seems to pay dividends and I have noticed an increase in the received signal by as much as a signal point when placing the earth wire just a few inches above ground, the earth helps reflect your signal into the sky and reduces the absorption or radio by the ground.
Connecting dipoles pruned for other ham radio bands and configured like a nest of dipoles or fan aerials will give you additional frequency allocations but my experiments have suggested that bands from 1.8 Megahertz up to about 10 Megahertz work best I have found twenty metres to be disappointing and ten metres was severely attenuated using this method however you may have completely different results if you live in an area where the ground has a high water content.
Using an N.V.I.S. aerial especially on the forty metre band is very affective if your interest is to work all Britain and apply for their awards, the aerial eliminates signal from continental Europe and experiments show that attenuation using the N.V.I.S. aerial is substantial when compared to a simple vertical aerial cut for the same band.
Feeding the aerial with twin 75 ohm cable works best, I have tried 50 ohm coaxial cable which works, however twin gives a much better reduction in noise.
This aerial works very well on the medium and long wave bands, at these frequencies propagation tends to follow the curvature of the earth.
A simple matching unit can be added to the feed point to bring the aerial into resonance.
John Allsopp G4YDM
Source: Southgate AR News
BROKE & FIXED
Nothing to report.
This section lists important announcements and possibly items from previous CCARC NEWS editions that are still current and may need your input:
Anyone reading this on the website who is not yet a member of the CCARC, please consider joining by emailing ccarc at ccarc dot org dot au for full details.
For submissions to this newsletter from CCARC club members please email the editor news-editor at ccarc dot org dot au
For what’s coming up in the next few months at the CCARC, please check the club calendar, accessible from the header on any page on the website.
Dave VK2DLS … News & Publicity Officer …