Jamboree On The Air 2024

Online EME relais-station

This fall, the Dwingeloo Radio Telescope will once again function as an online ‘Earth Moon Earth’ (EME) relay station. Scouting groups will also send signals to the moon with their self-built antennas during the international ‘Jamboree On The Air’(JOTA). The Dwingeloo telescope is very suitable for receiving the extremely weak EME signals due to its enormous sensitivity. These signals are offered over the internet by means of the CAMRAS webSDR. You can watch via this link: 70 cm EME, provided you have installed the special decoder software WSJT-X . The signal from the webSDR enters the software mentioned via a virtual cable. You should set the audio level to approximately “30dB” (“green”). The scouts use the mode “JT65” and “sub B” in WSJT-X and at the same time the option “EME delay” must be enabled so that the required 2.5 second delay is used. This delay is necessary to take into account the transit time of the moon echoes.

JOTA

On Friday 18 October and Saturday 19 October 2024 the radio telescope will be online between 17:00 UTC and approximately 22.30 UTC so that the JOTA participants can send messages to each other via the moon. The frequency on which the JOTA groups transmit is 432.050 MHz, as last year. What is new is that this year, in addition to the 70cm band mentioned, we will also stream part of the 23cm band (1296 MHz – 1298 MHz). Of course, non-JOTA stations can also use this opportunity to test their equipment, which is normally not really suitable for EME, for QRP EME. For example, a single Yagi antenna with sufficient elements with approximately 50W transmitting power can be considered. This is often sufficient in this situation because the Dwingeloo telescope is such a sensitive receiver. It would probably be fun to try this too? We kindly ask the non-JOTA EME stations to transmit around 432.100 MHz or higher so that the weak JOTA stations will not be hindered!

More info

The CAMRAS crew that provides the online streaming of the JOTA EME signals consists of Michel Arts (PE1NVK) and Simon Bijlsma (PA7SB). Download a report by Frans De Jong (PE1RXJ) of the test session of September 2, 2023 here . Moon phases see web page JOTA-JOTI downloads. Sixteen years ago, this JOTA-EME project was initiated by Frans de Jong (PE1RXJ) who wrote a construction description for the required ’23 elements Long-Yagi antenna voor de 70cm band’. See also the JOTA-JOTI page and the blog post about it from 2008.