G4NSJ – Radio Beacon 70cms Worthing West Sussex U.K.


21/11/22: G4NSJ Worthing 70cm CW Beacon. 432.491MHz. Locator IO 90 TT.

My RS41 Radiosonde has been reprogrammed, by my good friend Roy, to operate as a low power beacon on the 70cms amateur band.

CW frequency: 432.491MHz.
Ident: G4NSJ Worthing IO90TT.
Power: 100mW.
Time interval: 15 seconds.
Antenna: Sirio CX-425 at 30 feet.

Signal reports please to: [email protected]

Beacon status:

What is a Radio Sonde?

If you’re not sure what a Radiosonde is, there’s a load of information here.

The Beacon:

The photos below show the RS41 Radiosonde (not much to see) now operating as a beacon on 432.491MHz. The beacon was running on a 13.8 Volt power supply, via a Buck convertor to give 3 Volts. However, I now have a dedicated 3 Volt supply, shown in the photo on the right, eliminating the need for the convertor.

RSGB band plan 432.400 – 432.500MHz Propagation Beacons:

A small segment for Personal Weak Signal MGM Beacons at the top edge is available in the guard band. The idea of a beacon is to give some indication of propagation. At UHF, the beacon will be a useful bench mark for comparing receiving aerials.

2/12/22: Beacon now running on a Sirio CX-425 antenna at 30 feet:

Thanks to Roy for the antenna installation (see photo below). Scaffolding gone, the antenna is shown on the right, this is now the permanent antenna for the beacon.


Below is a short video of the beacon received two miles away. Thanks to Roy for the video clip. The beacon antenna was a Watson W50 at 40 feet. The CW speed is rather fast so I’ll be slowing it down at some stage.


11/1/23: Beacon heard 13 miles away:

The beacon was received today in Woodingdean, Brighton, at a distance of 13.5 miles. Below is the view from Woodingdean looking across to Worthing. For once, it’s not raining!


Woodingdean to Worthing view
Video of the beacon signal received on a mobile rig whip antenna on the hill at Woodingdean, Brighton. Thanks to Roy for the video clip and above photo.


24/11/22: G4WTV Worthing 70cm Beacon now on the air:

There’s now another beacon on the air. G4WTV cw ident on 432.493MHz. The G4WTV beacon is shown below in the attic along with homebrew J-Pole antenna. This is a temporary set up. An outside antenna will soon be in use for the beacon. Have a listen!CW frequency: 432.493MHz.
Ident: G4WTV IO90SU.
Power: 50mW.
Time interval: 30 seconds.
Antenna: 5/8 vertical.

Beacon status:
Beacon on air


G4WTV radiosonde beacon and antenna

14/12/22: A radiosonde balloon launch:

Thanks to Rusty Rocket for allowing me to use his video clip. Copyright C 2022 Rusty Rocket: You can find Rusty’s YouTube channel here.


Another beacon due on the air soon:

We’re beacon mad here in Worthing. There’s about to be another 70cm beacon on the air. Watch this space…