FSK, 3Hz separation, squarewave with 25 second cycle
Junkbox beacon construction:
This simple 30m QRSS beacon is built entirely out of junkbox parts, the only component purchased specifically for this project was the 10,140kHz crystal. The oscillator is in a polysytrene box made using pieces of packaging material and rubber bands, for protection from short-term temperature fluctuations such as drafts.
I use a full size half-wave dipole (14.2m) in my attic, taped to the roof at about 4 feet (1.3m) above the attic floor. At its centre is an 18-turn balun wound on a T130-2 toroid. The balun connects directly to the transmitter output using 5m of coaxial cable.
David VK6DI reported seeing a plain carrier that drifted around slowly. I thought it could be me, perhaps with a broken FSK pattern generator. I checked the beacon and found the fault. David VK6DI saw me make the change, on the other side of the world! Subsequently reports came from Larry WB3ANQ and Chris DL6JAN the following morning.
On 02-Mar-05, 1800 UTC I added 2,200uF capacitances in parallel with each of the two 470uF period determining capacitors in the astable multivibrator pattern generator. This caused the cycle time to increase to about 25 seconds. The slower pattern is more suitable for DX listening.
This map shows the worldwide reception of the G0UPL junk box beacon. Not all stations are shown on the map since some are geographically close to each other so overlap on the map. A full list of receiving stations is listed below. CLICK THUMBNAIL (left) to see larger photo
List of receiving stations
Currently reports have been received from 45 stations as follows:
Peter DL6NL has a QRSS frequency HC49 crystals for sale. He has the following frequencies: 7.000, 7.020, 10.137 and 10.140. Price is 5 Euros for three crystals, including shipping. Email him at his AOL address: