Showing posts with label EI1MMH. Show all posts
Showing posts with label EI1MMH. Show all posts

Thursday, April 10, 2025

Irish VHF beacon cluster is operational again - Apr 2025


Back in February of 2025, I had a post up about how the Irish VHF beacon cluster near Dublin was off air for the foreseeable future. In March, a new site had been found. The good news is that all the beacons are now operational from the new site.

The four beacons have an output power of roughly 20-30 watts and they all share the same directional antenna. The antenna is beaming at about 60 degrees (east-north-east). On any particular band, only 2-3 elements are active so the beamwidth is quite large.

Over a 10-minute period, this is the sequence...

Min    Callsign      Freq (MHz)   
0        EI0SIX        50.004 
1        EI1MMH    40.013   
2        EI0SIX        50.004   
3        EI1MMH    60.013   
4        EI4RF        70.013 
5        EI1MMH    40.013  
6        EI0SIX        50.004    
7        EI1MMH    60.013   
8        EI4RF        70.013  
9        EI1MMH    40.013 

The transmission sequence for each one of the minutes is a short carrier, then THREE x FT8 15 second transmissions and then the callsign and locator of the beacon in CW (morse code).

New beacon location... The new location is about 4kms to the south of the old site and it's a bit lower in altitude. It's certainly not as good as the old site but the challenge for any amateur radio beacon is to find any site where a beacon can operate.

The new site is nestled in the foothills of the Wicklow Mountain just to the south of Dublin and then local mountains and hills will certainly have a major impact in certain directions.

This is the approximate horizon of the new site...


To the north-east and on a heading of about 40 degrees, the Irish Sea is visible and there is a very good path to the Isle of Man and Scotland.

As we move further south, the local terrain starts to become more of an issue. The take off to the north of England is reasonable but once we go below a line say running from Liverpool to Leeds, it gets to be more challenging.

For example, the horizon in the direction of London and the south-east of England is about 6-degrees which will make reception difficult especially on tropo. 

To the south-west of Ireland which is in my direction here in Cork, the horizon is about 14 degrees which effectively kills all signals.

This map shows where tropo signals might be heard and the maximum range for one-hop Sporadic-E.


The range for single hop Sporadic-E to northern Europe is pretty good but the maximum range to Spain and Italy is shorter due to the mountains near the beacon site.

If you live in say England then be sure to check for the beacons during auroral conditions. There are also a lot of planes going in and out of Dublin airport so getting a FT8 decode from aircraft scatter is a distinct possibility if you live in the UK or Ireland.