MICROWAVES IN THE UK

The Microwave region of the spectrum strictly begins at 3GHz but amateurs traditionally refer to all the bands above 1GHz as microwave bands.  It is perhaps the most challenging and technically progressive area of amateur radio. With the exception of kits and modified ex-professional gear, there is very little commercially built amateur equipment for any of the microwave bands - apart from 1.3 and possibly 2.3GHz.  It is also an area of the spectrum that is under sustained pressure, where many different (and often conflicting) demands are made for frequency allocations by commercial, government, military, domestic and amateur users. Never has there been a more appropriate time to remind all amateurs of the need to "use it or lose it"!

IARU Region 1 Microwave Band Plan

The present band plans and allocations can be downloaded by clicking here

Amateur band microwave band usage

Due to the technically challenging nature of the microwave spectrum,  the levels of activity look low when compared to the more widely known HF bands such as 80m, where it is much easier to build up a station of ready made equipment. Almost all microwave operators build their own transmitting and receiving equipment and often have sophisticated test gear not usually found in the average amateur enthusiast's "shack".

Operating modes on the UK microwave bands are mainly narrowband types (SSB/CW and, occasionally, NBFM/FSK) and wideband modes such as ATV. There is also some interest being shown in data modes.  Much operation is at terrestrial level but there is also a great (and growing) interest in communication via satellites and E.M.E (Earth-Moon-Earth, or "moonbounce")

All these specialised areas within amateur microwaves create their own special conflicts of interests and require spectrum management of a higher degree than is perhaps required at lower frequencies.

The most active microwave bands in the UK are the 23cm (1296MHz) and the 3cm (10GHz) bands, the former having several hundred UK operators with working equipment and the latter with around 100 if not more.  There are also many enthusiasts who spend much of their time building and testing equipment rather than operating.

In recent years there has been an upsurge in amateur operations on the millimetre bands, i.e. 24GHz, 47GHz, 76GHz and higher.

The so called "middle microwave bands" of 2.3GHz, 3.4GHz and 5.7GHz have also seen a rapid increase in activity in the past few years, largely due to the availability of excellent kit sets from both the UK and overseas.

There are high levels of activity on the Continent on nearly all the amateur microwave bands The European stations are often workable at distances up to about 1000km or more by UK microwave operators, using  with modest equipment, but with good knowledge of propagation, the European microwave beacons providing excellent indicators of such favourable conditions.

A casual tune across any of the microwave bands will usually fail to find any amateur signals other than beacons. This is because of the highly directional nature of the antennas being used. Beam widths of 5 degrees or less are common. A casual listener may therefore be forgiven for thinking the bands are not being used. This is far from the case. Every month of the year sees organised activity in the form of contests (often two a month) and activity days. There is also a strong contingent of home stations who operate on a regular basis (Monday evening being the traditional "microwave activity night"). Due to the directional nature of antennas, some form of liaison is necessary, often on the 144MHz and 432MHz band as well as via the Internet where a dedicated microwave chat room has been set up.

Microwave Beacons

There is a well developed network of microwave beacons in the UK, on all bands from 1296MHz to 47GHz.  A list can be found at www.g3pho.org.uk.

Applications for unattended beacons are coordinated through RSGB. Beacons are very much welcomed as they provide not only the amateur fraternity with most useful propagation and frequency indicators but are also used by government, university and commercial organisations.

Representation

In matters of spectrum allocation and licensing matters, UK microwave enthusiasts are presently represented by the RSGB and its Spectrum Forum. The RSGB Microwave Manager is Murray Niman G6JYB. He in turn is supported by the UK Microwave Group (UKuG), which is an RSGB Affiliated Society. UKuG is an independent organisation with some 250 members and issues a monthly newsletter (Scatterpoint) as well as organising almost all the microwave contests and activity days for the country.

In addition, UKuG runs its own website at http://www.microwavers.org together with a microwave email reflector (open to all, regardless of membership status of UKuG). Details of the latter, as well as membership information, can be found on the Group’s website.

All matters of concern with respect to microwavers should be sent, in the first instance, to the UKuG Chairman (chairman@microwavers.org) who will then forward the item to the RSGB Microwave Manager.

24 and 77GHz Operation

24-Feb-2005: Ofcoms reply to UKuG and similar submissions by Amateurs has resulted in the following response being included in the Ofcom decision on 79GHz automotive short-range radar: 'Ofcom is aware of Footnote EU35 of the European Frequency Tables and will take all necessary steps to permit Amateur and Amateur Satellite Services to use 75.5-76GHz after 2006'. When implemented this will permit many UK operators to remain on their current frequencies.

On 17-Jan-2005 the EU endorsed the use of 24GHz (actually 21.65-26.65GHz) as an interim band for SRR.  Noting Amateur and other concerns, Ofcom 'will consult with interested parties' in due course.

The original UKuG submission and full Ofcom response can be found at the UK Microwave Group's  Operating Section

Further information can be obtained on the Ofcom 79GHz website

Joint RSGB/UK Microwave Group/AMSAT-UK response on Ultra Wide-Band (UWB)

The Radio Society of Great Britain, the UK Microwave Group and Amsat-UK have published a joint response to European plans to allocate spectrum space to Ultra Wide Band (UWB), a wireless version of the popular USB technology that is used to connect devices such as mice and keyboards to computers, but can also be used for the higher data rates needed for PC monitors, wireless DVD players and HDTV.

UWB is unlike other radio technologies in that it generates short pulses made up of lots of frequencies, rather than modulating a signal on a particular carrier frequency. This approach, known as carrier-free radio, allows massive amounts of information to be transferred quickly.

However, there are serious concerns that the technology could threaten the amateur microwave bands, especially if it were used outdoors as an alternative to wireless network technologies like Wi-Fi.

In the response, the RSGB and its partners wrote: "We recognise that UWB short-range links will have a useful role and observe that UWB vendors are exerting considerable pressure for UWB's adoption. We stress that UWB must fully comply with the International Radio Regulations and that all such devices must operate on a non-protected, non-interference basis."

Under a draft ECC Decision, the European Union suggested that UWB transmissions would principally be in the 3.1-10.6GHz range. This range encompasses a number of amateur radio and amateur satellite service bands, creating the possibility of interference.

The RSGB and its partners are therefore calling for the technology to include masking to protect the amateur bands. "In order to protect our services (notably in the 3.40-3.41GHz band) we urge the adoption of the mask proposals without due concession to UWB proponents," they wrote in their response.

The RSGB and its partners are also worried that the ECC Draft Decision has underestimated the amount of outdoor UWB usage that will take place and have urged that "to avoid harmful interference, it is important to minimise the outdoor activity of UWB". Despite such concerns, the RGSB, the UK Microwave Group and Amsat-UK are largely supportive of the draft ECC Decision. "In general, we applaud the draft decision and would urge its adoption subject to reservations we have at 3.4GHz and outdoor usage.

 A copy of the joint paper can be downloaded by clicking the following link.

July 2007: Joint RSGB/UK Microwave Group/AMSAT-UK comment on Ofcom's implementation of the European UWB decision