Radio communications and tourism
Apr 30, 2021 at 2:44 pm
📢 SSTV HF experiment "SURA". A very unusual shortwave SSTV experiment.
Transmitter with power over 150 kW
Antenna field of 144 shortwave dipoles
⏰ When: May 7, 2021
Research Radiophysical Institute in Nizhny Novgorod
invites radio amateurs to take part in an interesting experiment on receiving radio signals reflected from the ionosphere.
Participation in the reception of these signals and personal informing about the presence of such a reception of the organizers of the experiment will determine the area of ​​operation of transmission and reception of radio signals and reasonably confirm the correctness of the selected parameters of the experiment.
➤ Technical details and experiment times
▸ Transmission of HF signals through reflection from the ionosphere for their wide-band reception;
▸ Transmission of HF signals is organized by NIRFI (Research Radiophysical Institute in Nizhny Novgorod) using a powerful radio transmitter (at the SURA stand)
✽ Explanations:
▸ On May 7, 2021, we are scheduled to air a set of images dedicated to Radio Day!
▸ Air time: from 11:00 to 12:00 Moscow time (from 8:00 to 9:00 UTC), as well as from 16:00 to 17:00 Moscow time (from 13:00 to 14:00 UTC). The rest of the time will be used for preventive broadcasts.
▸ Transmission format and reception parameters:
- Slow-scan TV (SSTV) Robot36 - similar to that used on the ISS;
- Modulation: FM;
- Bandwidth: 5 kHz (max.frequency deviation - 2.5 kHz);
- Central frequency: one of the permitted for the SURA stand (4300, 5227, 5828 kHz). The specific frequency value will be selected based on the ionospheric conditions (it will be communicated via the website 3 hours before the broadcast);
- Duration of transmission of a message (image) - 36 seconds. The start of the next message will coincide with the beginning of the minute. Message period - 60 seconds (radiation lasts 36 seconds, pause 24 seconds);
- Software required for image registration: MMSSTV for Windows or, for example, Robot36 - SSTV Image Decoder for Android phones;
- The receiver must be able to demodulate the FM signal into sound. The sound can then be decoded into an image by the applications mentioned above. The image is stored in memory.
Please send your registered images to the NIRFI e-mail box. It is advisable to indicate in the letter the location of the collection point, as well as describe the equipment used. We will definitely answer everyone by sending the originals of the emitted images and a document confirming your participation in the experiment.
➤ Preliminary results and plans:
▸ At the moment, one PKV-250 transmitter of the SURA stand is ready to go on the air, which reached a power of 150 kW on April 9. The antenna field consists of 144 dipole antennas. On May 7 we will try to increase the capacity.
▸ We plan to reach the maximum power of 750 kW generated by three PKV-250 transmitters closer to August. At this time, larger-scale events of this kind will be scheduled, timed to coincide with the 800th anniversary of Nizhny Novgorod, which we will definitely announce to the entire radio amateur community of the world!
Directorate of NIRFI with the participation of NRO NTO RES them. A.S. Popov.
Google translation of RUS-DX item:
https://vk.com/dxing?w=wall-3271973_5703
(via WOR io group)