Antenna upgrade for the GB3NGI 432 MHz beacon


The GB3NGI beacon transmits on 432.482 MHz on the 70cms band and it is located on the summit of Slieve Annora in County Antrim in the north-east of Ireland. The site is 500-metres above sea level and it’s locator square is IO65VB.

It has as far as I know been operational since 2014 and beams to the south-east towards London.

The beacon keeper Gordon, GI6ATZ reports that the antenna system has now been updated…

GB3NGI 70cms Beacon: – The single 70cms yagi was replaced today (22nd Nov 2022) by a pair of Antenna- Amplifiers 9 ele yagis beaming NE and SE

This should improve the coverage quite significantly up to the NE and whilst in theory it should be at least a 3dB reduction in power to the SE my initial test here show a significant increase in signal strength – but then I am relatively close to the beacon!

The old antenna had suffered quite a bit of damage and I suspect the driven element assembly was full of water. 

Would appreciate signal reports with the new antenna system particularly from the NE but also from the SE to see if people notice any improvement/reduction in signal strength. 

The map above shows the location of the beacon and the new beam headings of 45 degrees (north-east) and 135 degrees (south-east). 

In the past, areas like Glasgow and Edinburgh were on the side of the old beam so the new system should result in a much stronger system.

The beacon has an RF output power of 20 watts and transmits JT65b on the even minutes and CW on the odd minutes in the following sequence: –

00:01 – 00:51 GB3NGI IO65VB in JT65b mode
00:52 – 01:00 GB3NGI IO65VB in CW
01:01 – 01:29 Plain Carrier
01:30 – 01:40 GB3NGI IO65VB in CW
01:41 – 02:00 Plain Carrier
The sequence then repeats

To decode the JT65b, tune the carrier to obtain a tone of 1500Hz with the receiver set to USB, and the dial frequency reading 432.4805. The JT65b will then be tuned in correctly.

The antennas used for the 432 MHz beacon are a pair of 9-element Antennas-Amplifiers Yagis designed and built by Goran YU1CF :-

Additional information…

1) GB3NGI website


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