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Q & A: How far you can turn the dial when transmitting in SSB voice mode?
· HF, Spectrum · admin

Time and again the question arises as to how far you can turn the tuning knob when transmitting in SSB voice mode. Up to the edge of the band range? Using the 60 m band as an example, we will discuss the question here.

According to WRC-15, the range from 5351.5 to 5366.5 kHz, also called the “5 MHz band”, is allocated to the amateur radio service on a secondary basis. So, for example, are radio amateurs allowed to transmit on 5366.0 kHz within the WRC-15 60 m band in USB? [1]

The so-called “dial frequency” indicates only the frequency of the carrier suppressed in SSB. However, the modulation range for USB extends up to 3.0 kHz higher. That means 5366.0 kHz + 3 kHz = up to 5369.0 kHz. This means that a large part of the signal is outside the range assigned to the amateur radio service (see diagram, right signal, in red)! And: parts of the modulation spectrum cover the section intended for “narrow band weak signal modes”, such as WSPR. And thus leads to interference.

Therefore, the band plan indicates in the “notes”, that in the case of the 60 m band in USB, the highest “dial frequency” to be set is 5363 kHz (diagram, left signal, in green). Here the whole range of the modulation spectrum is below 5366.0 kHz. And thus both within the band and outside the “weak signal narrow band mode” range.

The same applies to the 20 m band: The highest frequency to be set in USB would be 14,347.0 kHz — i.e. 3 kHz below the upper band limit.

[1] Note: Individual countries have allocated a larger frequency range to the amateur radio service due to Radio Regulations Article 4.

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The IARU has agreed the first preliminary IARU positions for WRC-23
· SpectrumTagged , · Barry, G4SJH

The preparatory work for WRC-23 has started across all regions in both the ITU‑R and the Regional Telecommunications Organisations (RTO’s). The IARU has representatives in these RTO’s and the ITU‑R contributing to the studies and helping to develop the regional positions on all the WRC agenda items. It is vital that the amateur community presents its views in a consolidated and consistent manner on each WRC agenda item across all the regions.

To this end the IARU Administrative Council (AC) has agreed the first preliminary positions covering the six most important agenda items for the amateur and amateur satellite services.

The IARU SRLC asks that the regional representatives and the member societies take careful note of these positions and follow them when discussing WRC related matters with their national regulators.

The IARU WRC-23 preliminary positions can be found here.

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Electromagnetic Compatibility — evaluation of the EU Rules
· SpectrumTagged , · Nestor, 5B4AHZ

IARU is acutely aware of the concerns of Member Societies and radio amateurs about the threat of increasing levels of noise and harmful interference.

The EC EMCD evaluation process is currently open for Public Consultation. This Public Consultation is an opportunity for IARU Member Societies and individual radio amateurs to let the European Commission have their opinion on the effectiveness of the EMCD.

IARU has already participated in the process since its beginning and has ongoing involvement through PRC as a member of the Commission’s EMC Working Party.

Furthermore there has been significant constructive input to the process from radio amateurs. 

IARU encourages its Member Societies and individual radio amateurs to respond.

The link to the consultation is at:

https://​ec​.europa​.eu/​i​n​f​o​/​l​a​w​/​b​e​t​t​e​r​-​r​e​g​u​l​a​t​i​o​n​/​h​a​v​e​-​y​o​u​r​-​s​a​y​/​i​n​i​t​i​a​t​i​v​e​s​/​1​1​8​6​8​-​E​l​e​c​t​r​o​m​a​g​n​e​t​i​c​-​c​o​m​p​a​t​i​b​i​l​i​t​y​-​e​v​a​l​u​a​t​i​o​n​-​o​f​-​t​h​e​-​E​U​-​r​u​l​e​s​/​p​u​b​l​i​c​-​c​o​n​s​u​l​t​a​t​ion

Should you require any assistance please contact the PRC Chair Séamus EI8BP (ei8bp@​iaru-​r1.​org)

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IARU is fully engaged in the 23cm band/Galileo radio navigation satellite service coexistence studies in CEPT
· SpectrumTagged , , · Barry, G4SJH

Throughout 2020 the IARU has been busily contributing to and participating in the work of CEPT Project Team SE40 concerning the 23cm band Galileo/GLONASS coexistence topic. Project Team SE40 conducts technical studies relating to space services under the direction of the CEPT/ECC Spectrum Engineering working group WG-SE and was assigned the task at the beginning of 2020. During this year the IARU R1 has provided 7 written contributions and 2 information documents providing the necessary details of amateur applications and activities specific to the 23cm band to enable SE40 to carry out the coexistence studies.

The last SE40 meeting in 2020 was held from 2nd to 7th December and the IARU R1 was represented by Barry Lewis, G4SJH (Region 1 SRLC chair). At that meeting the draft project team working document was further developed with the addition of the Galileo ground-based receiver protection criteria which are needed for the coexistence studies. Without these criteria no meaningful studies have been possible, however now it can be expected that the technical studies will begin in earnest as we move forward into 2021.

This work is also important in the global preparations for the next World Radio Conference where this topic is on the agenda as item 9.1b. To address this the ITU‑R Study Group Working Parties 4C and 5A are working on the issue but with a wider scope covering the global set of radio navigation satellite systems (RNSS) operating in the band 1240 – 1300 MHz.

The IARU supports the action to do this work in CEPT but continues to hold a view that the potential for interference being caused by the amateur and amateur satellite services to the RNSS is being over-stated.

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