In 2019, a joint document submitted to the CEPT CPG meeting in Ankara by France, Lithuania, Malta, Slovenia and the Netherlands showed a lash against amateur radio stations for continuing to use the 1240-1300 MHz band. There have been several recent cases of interference with Galileo E6 receivers caused by radio frequencies from amateur radio services, sometimes over long distances that can take hours or even days to eliminate. There is therefore serious concern that as Galileo E6 receivers become more widely deployed and used, the interference situation on amateur radio stations will increase rapidly.
Recently, IARU released a test report to use experimental data to intimidate amateur radio stations to interfere with GPS receivers, and today I will look at it with the radio uncle BG5WKP!
IARU simulations confirmed that amateur stations have a low probability of interference to RNSS receivers in the 23cm band
文：Spectrum· Barry, G4SJH
WRC23 - Agenda item 9.1b
IARU insists that there is little chance of widespread and sustained interference from amateur radio activity to 23cm band RNSS (such as Galileo) receivers. The WRC-23 preparatory study conducted by ITU-R Study Group considered only static one-to-one estimates using the minimal coupling loss method. These studies did not consider the effects of amateur radio transmitters on the RNSS receiver population deployed around amateur transmitters.
So IARU volunteers conducted a "Monte Carlo" study, simulating scenarios that assumed a fixed and mobile population of RNSS receivers deployed around amateur radio stations. Suppose there is a 100W amateur "master" and a 25W EIRP "relay station".
The simulation results showed that among fixed and mobile RNSS receivers randomly located around the location of the transmitting amateur radio station, at most only about 1% had a small chance of receiving a signal level above the RNSS protection threshold established in the relevant ITU-R Recommendation. In most cases, the percentage of RNSS receivers affected by interference above the threshold within the "analog region" is well under 1%. Even in areas with the highest concentration of amateur radio activity and the lowest clutter model, the percentage is still below 5%.
The study hypothesized that an amateur radio station would transmit throughout the "Monte Carlo" trial. However, the event data collected by IARU shows that even in the busiest amateur communities, these sporadic transmissions are most likely to occur less than 2% of the time in a year.
Therefore, IARU maintains its position that the likelihood of widespread and persistent interference between amateur radio transmissions and RNSS receivers is minimal.
The threat to the 23cm band of amateur radio is coming? This time is actually Europe's Galileo satellite navigation system, and the recently staged battle for frequency resources has intensified, isn't this a clear robbery? Let's find out with the radio uncle BG5WKP!
Direct microwave band 0.23m band (1260.00~1300.00MHz)
Many radio amateurs will use this frequency band to conduct ultra-long-distance communication experiments such as meteor residual reflection and tropospheric scattering. Because the frequency is high, water vapor and raindrops also cause losses to radio waves. However, because the frequency band is very wide, in addition to conventional communication, amateur digital communication and amateur television communication experiments can also be carried out.
A joint document submitted to the CEPT CPG meeting in Ankara by France, Lithuania, Malta, Slovenia and the Netherlands shows an attack on amateur radio stations for continuing to use the 1240-1300 MHz band.
This is the final CEPT CPG meeting in preparation for the ITU World Radiocommunication Conference (WRC-19) to be held in Sharm el-Sheikh, Egypt, from 28 October to 22 November. The meeting will identify agenda items for WRC-23.
AI10 - The proposal for AS-RNSS says:
The Galileo Galileo satellite system is nearing full operational capability, and its E6 signal in the 1260-1300 MHz band will support new services, such as the free-to-use Galileo high-precision service, as well as strong authentication, which is expected to be used in a variety of applications, including autonomous vehicles and the Internet of Things (IoT).
There have been several recent cases of interference with Galileo E6 receivers caused by radio frequencies from amateur radio services, sometimes over long distances that can take hours or even days to eliminate. There is therefore serious concern that as Galileo E6 receivers become more widely deployed and used, the interference situation on amateur radio stations will increase rapidly.
Item WRC-23 is a sine qua non for addressing this issue because:
1. Unregulated use of the 1240-1300 MHz band by amateur services is a serious source of harmful interference with RNSS receivers. This experience proves this.
2. The number of Galileo receivers at 1260-1300 MHz will increase sharply, and if it is not dealt with in time, the interference situation will multiply.
3. Galileo and other RNSS systems will be deployed globally, and interference situations between amateur radio transmissions and RNSS receivers include cross-border situations. The issue was therefore of an international character and would be addressed within the framework of ITU.
4. Galileo is a major asset for Europe, and the decision of WRC-23 is essential for compatibility with the roadmap for the deployment of Galileo receivers in this frequency band.
Download the proposal: AI10 - Proposal on AS-RNSS
https://cept.org/ecc/groups/ecc/cpg/client/meeting-documents/?flid=10031
See also IARU document: RNSS proposal WRC-19 AI 10 at the same URL
January 2006 - Peter Blair G3LTF operating from the 23cm band potential interference to Galileo
http://www.southgatearc.org/articles/galileo.htm
Tom WA4ILH:
Unfortunately, (for our amateurs) the 1240-1300 band is allocated on a secondary basis for amateurs. There are not only four main other allocations in this band, but at least some of them may be considered "life safety" services. I won't hold my breath. Too bad, 23 cm is an interesting band.
Carl Arne SM0AOM:
Traditionally, the main main user of the 1240-1300 MHz band is the main surveillance radar (PSR) for air traffic control and air defense.
These radars are now obsolete in Europe and have been replaced by C-band and S-band radars in some countries. This relieves radiolocation users of the pressure on the band, and instead, radionavigation and earth exploration take their place.
Galileo waveforms have been tailored to handle possible radar interference from PSR and Earth exploration satellites, but not for interference with less defined and predictable spectral masks. The cases of jamming reported by Amateur Radio came from ATV repeaters in northwest Europe.
The design parameters of the Galileo system also take into account the secondary state of amateur radio, relying on the procedure outlined in the "Radio Regulations" to mitigate the interference of secondary users (= reduce the power or eliminate them altogether).
"5.28 3) Secondary service stations:
5.29 a) shall not cause harmful interference to major service stations that have already been assigned frequencies or can be assigned frequencies at a later date"
...
"15.2§2 The transmitter shall radiate only the power necessary to ensure satisfactory service.
...
15.9§5 Stations shall adopt emission categories that minimize interference and ensure efficient use of the spectrum. In general, this requires that every effort should be made to minimize the bandwidth occupied when selecting emission classes that meet these objectives, taking into account the operational and technical considerations of the services to be performed.
Europe's spectrum regulators largely treat amateur radio as irrelevant, so they will limit or eliminate the allocation of amateur radio spectrum if there are concerns about spectrum use or interference potential.
It should be borne in mind that no national authority may be compelled to allow the use of amateur radio in a particular frequency band, even if it should be displayed only as an amateur radio in the ITU Schedule of Frequency Allocations (Article 5).
A precedent is the measures taken by some countries to protect WiFi and short-range devices from amateur radio emissions in the 13-centimeter band.
The Galileo system represents a multi-billion dollar investment whose social value exceeds that of amateur radio by orders of magnitude.
WY7BG：
This is the current trend: companies are greedy for spectrum, for themselves, and for mobile phones and id-IoT devices used to spy on the public. (Make no mistake: the European Galileo system will be used primarily by commercial entities, not the military.) ）
What's more, the companies want to build devices at low cost, without even decent midway input filtering, which will allow other users to use nearby spectrum. (Witness the latest failure LightSquared recently experienced in the United States, where the presence of GPS devices with poor filtering is cited as the reason for the refusal to use nearby spectrum for broadband.) ）
For this reason, ham, as well as the satellite industry and almost all other spectrum users, are in their crosshairs. You'll hear more and more talk about the "5G race" (even if there is no technology like 5G; It's all 4G LTE plus marketing hype), which will become an excuse to offer more and more spectrum to mobile carriers/IoT vendors. Over the next decade, all other users of the radio spectrum will have to work to keep it to its smallest band.