The World's Oldest Ham Radio Beacon
OZ7IGY - Next Generation Beacons
The world's oldest beacon · OZ7IGY in JO55WM · 28 MHz to 24 GHz.
OZ7IGY goes all the way back to the International Geophysical Year in 1957. From its start on 144 MHz it has been on air on more and more bands. Today OZ7IGY transmits on 28 MHz, 40 MHz, 50 MHz, 70 MHz, 144 MHz, 432 MHz, 1,3 GHz, 2,3 GHz, 3,4 GHz, 5,7 GHz, 10 GHz and 24 GHz. Most of the HF, VHF and UHF technology used by OZ7IGY was old(er) land mobile equipment modified for the purpose. For the microwave bands most of the technology is dedicated radio amateur beacon designs while power amplifiers are surplus.
Given the latest developments in digital modulation techniques and RF-circuits it was time for OZ7IGY to take advantage of these technologies. On 30 October 2012 the first two Next Generation Beacons were put on air. The Next Generation Beacons platform is open to others and the software can easily be adapted to other modulations and sequences. Furthermore, is the new platform frequency and time locked to GPS. Thus the frequency accuracy is better than 5 mHz. Emanuele, IW9GDC and beacon manager of IW9GDC/B that also uses the Next Generation Beacons platform says: "... I can really say that this hardware is actually the best ever made ... 4 km straight line and cannot detect any issue with the signal."The new beacons on 28 MHz to 432 MHz transmit in a 1 min sequence starting with PI4 (call) then CW (call and locator) and finally a carrier until next cycle begins at the 00 second. Over time all the OZ7IGY beacons will use the Next Generation Beacons platform.
PI4 decoded spots
Here is a number of OZ7IGY YouTube videos.
The OZ7IGY Next Generation Beacons transmit, in a 1 minute cycle starting at the full minute. The colored line below illustrates the mixed mode sequence where P indicate pauses. The CW is sent at 60 LPM/12 WPM.
First it sends PI4 (callsign), that last 25 s including the subsequent pause, then followed by CW identification (callsign and locator) and carrier until end of the cycle. The resulting waterfall and decoding in PI-RX will look like the screen dump below. To decode a PI4 signal you will have to set your receiver to the same frequency as of you would do to receive a beacon with an 800 Hz carrier. The receiver bandwidth should not be less than 1 kHz. On most receivers you will have to set your USB dial 800 Hz lower than the nominal frequency, e.g. OZ7IGY is assigned to transmit on 50,471 MHz thus the receiver must be tuned to 50.470.200 to show a 0 Hz frequency deviation. When you receive the carrier at exactly 800 Hz then you know how accurate your station is.
PI4 decoding of OZ7IGY and carrier measurement using PI-RX by Poul-Erik, OZ1CKG.
The reason for using PI4 for the OZ7IGY beacons is related to the below requirements:
PI4 is specifically designed with beacons and VUSHF propagations in mind. It is far more robust to path irregularities and equipment inaccuracies than e.g. WSPR and JT9 that both also would require a long sequence. JT65, modes are in-between WSPR/JT9 and PI4, and JT4, when it comes to robustness but cannot fulfil an identical sequence every minute without other sacrifices unless using the JT65B2/C2 submodes. The JT4 submode JT4G has better path robustness than PI4 but takes about twice as long to transmit thus it will not fulfil the sequence requirements. PSK2K, FSK441, JT6M and ISCAT are "fast modes" but are not as sensitive as the other modes. Because of this is PI4 the MGM used by the OZ7IGY Next Generation Beacons.
Elevation and horizon maps
The OZ7IGY building is 85 mASL and the antennas are from 5-10 mAGL.
Elevation map 10 x 10 km. OZ7IGY is located at the black dot in the center of the map. Courtesy Radio Mobile and Uffe, PA5DD.
Elevation map 1000 x 1000 km. OZ7IGY is located at the red dot in the center of the map. Courtesy Radio Mobile and Uffe, PA5DD.
Visual horizon map. Courtesy Radio Mobile and Uffe, PA5DD.
We appreciate your feedback so please send it to Ivan, OZ7IS, at his_callsign @ yahoo dk.
For technical questions about the Next Generation Beacons platform please contact Bo, OZ2M, at his_callsign @ rudius net.
User webpages and Youtube videos