Licence Conditions
In the UK the 50MHz (6M) band between 50.0-51.0MHz is allocated with Primary status. The power limit for Advanced Licensees is 400W (26dBW), Intermediate Licensees power limit = 50W (17dBW) and Foundation Licensees power limit = 10W (10dBW).
Between 51.0-52.0MHz it is allocated with Secondary status with a power limit of 100W (20dBW), available on the basis of non-interference to other services inside and outside of the UK.
The permitted modes on the 6m band are Morse (c.w.), telephony, data, facsimile (Fax) and radio teletype (RTTY).
UK 50MHz Band Plan
The idea behind band planning is that it assigns frequencies for certain activities in such a way that all current users can practice the various modes of amateur radio with a minimum of mutual interference.
The 50MHz UK band plan is based on the International Amateur Radio Union (IARU) Region-1 band plan. The plan shows the frequency limits of individual 'sub-bands' or segments. The allocation of sub-bands enables the indicated category of users to employ any frequency within that sub-band provided that no appreciable energy falls outside that sub-band. Users must therefore take into account the bandwidth of their sidebands when selecting an operating frequency.
The ‘Transmission Bandwidth’ determines the maximum spectral width (-6dB points) of all emissions recommended in a sub-band. The ‘Mode’ indicates the modulation methods (e.g. telegraphy, telephony, machine generated mode) allowed in a segment. A machine generated mode (MGM) indicates those transmissions relying fully on computer processing, for example JT6M, JT65, PSK31 or RTTY.
The ‘Usage’ column indicates the main usage of a sub-band or segment. It contains meeting/calling frequencies agreed upon for the convenience of the v.h.f. operators practising specific modes of communication. These frequencies are not part of the adopted 50MHz IARU Region-1 Band Plan and although in the normal amateur spirit other operators should take notice of these agreements, no right on reserved frequencies can be derived from a mention in the usage column.
A detailed look at the 50MHz Band Plan
50.000 - 50.100 MHz Telegraphy (c.w.)
This 100 kHz wide sub-band is allocated exclusively to telegraphy (c.w.) stations with a maximum transmission bandwidth of 500Hz. The area between 50.000 – 50.080MHz however has been designated for beacon stations. The primary purpose of beacons is the checking of propagation conditions both for every day amateur use and for special propagation research projects.
The remaining 20kHz between 50.080 – 50.100MHz is also nominated exclusively for CW although it should be noted that telegraphy is permitted over the entire 50MHz band.
50.100 – 50.500 MHz Narrowband modes (c.w./s.s.b./m.g.m.)
Narrowband modes with a maximum bandwidth of 2.7 kHz in common with all v.h.f., u.h.f. and microwave band plans are always found at the bottom of individual allocations. This is where you will find Morse (c.w.), telephony (s.s.b.) and machine generated mode (m.g.m.) activity such as JT6M, JT65A and PSK31.
It is very important to note that the area between 50.100 – 50.130MHz is the DX window designated for c.w. and s.s.b. contacts between continents only, such as Europe to South America or Europe to Africa. This area of the band should **not** be used for making QSOs within Europe. The same comment is particularly true of the DX calling frequency 50.110MHz which should only be used to establish contacts with stations in other continents before moving away to another frequency.
Most Europe-wide c.w. and s.s.b. activity will be conducted between 50.130 - 50.200MHz although you should be aware that some countries (such as France) do not have the same band allocations as in the UK.
Cross-band activity is still common, for example between 50MHz and 70MHz and the frequency of 50.185MHz is recommended for this purpose.
Although 50.200MHz is designated as the meteor scatter centre of activity there is little, if any, activity via this mode on this frequency. Although it does not appear in any formalised band plan the area between 50.190-50.210MHz is currently being used for Moonbounce (e.m.e.) operation using JT65A.
Meteor scatter operation using JT6M can be found between 50.210 – 50.250MHz. Initial transmissions are made on 50.230MHz, the centre of JT6M activity.
50.500-52.000 MHz All Modes
This area of the Six Metre band is allocated to any mode with a maximum bandwidth up to 12.5 kHz and is where you can find a mixture of telephony and digital modes that include f.m. simplex and repeater channels, packet radio, Internet voice gateways, automatic packet reporting systems (a.p.r.s.), facsimile (fax), radio-teletype (r.t.t.y) and slow-scan television (s.s.t.v.).
Within the UK a total of 16 f.m. repeater channels spaced 10kHz apart have been allocated. The input frequencies lie between 51.220 – 51.370MHz with the outputs shifted 500kHz lower between 50.720 – 50.870MHz.
Further up the band you will find a total of 10 f.m. telephony simplex channels. These lie between 51.410 -51.590MHz, each spaced 20kHz apart. The centre frequency 51.510MHz is designated as the f.m. calling frequency.
Although the usage column of the band plan indicates that some channels are used by digital modes, internet voice gateways or emergency groups that does not mean you cannot use them for your own communication purposes. It is simply a case of listening on any channel to ascertain locally whether it is in use or not. If you hear no other traffic then you may conduct your contact on any channel you wish to use.
Getting Started
One of the reasons why the Six Metre band has become very popular is the availability in recent years of multimode (c.w./s.s.b./f.m.) transceivers that cover not only the h.f. bands but also include the 50MHz band. Your choice of antenna is normally dictated by the communication modes that you want to use. If you are only interested in local f.m. communication then you should invest in a vertical antenna as this will give omni-directional coverage. If however you want to work long distances (DX) on s.s.b. or c.w. then it's best to have some sort of horizontally polarised beam antenna. That's not to say you can't work DX with a dipole or a vertical antenna. It just means you stand much more of a fighting chance when using a beam antenna with a bit of gain. As a start you could try a simple 2-element Yagi and perhaps exchange it for something more ambitious when the bug catches.
Propagation Modes
One of the great attractions of operating on the 50MHz band is that it experiences propagation modes common to both the v.h.f. and h.f. bands. The v.h.f. modes include tropospheric (tropo) propagation, Aurora, Meteor scatter (m.s.), trans-equatorial propagation (t.e.p.) and E-layer propagation, the most common type being Sporadic-E (Sp-E).
The h.f. characteristics experienced on the 50MHz band are directly linked to the state of the sun spot cycle. The prime DX mode is F2-layer propagation and occurs during the years around the peak of the solar cycle. This should occur around 2012 and when it arrives you’ll certainly know about it. The 50MHz band will literally be open to all continents for months at a time.
The pursuit of working world-wide DX is one of the reasons why so many people become addicted to the magic band. The interesting point is that high power and large antennas are not necessary to work long distances. During the summer Sp-E season you can easily work all around Europe with only 10W and a dipole. Many operators including novice licensees accomplish this every year and it is because of the intensity of some of these openings that surprising results can be achieved with very low power.
And the same is equally true when F2-propagation returns. During the last peak in solar activity many low power stations made contacts into North America, South America, Africa, Asia, even as far as Australia on the 50MHz band. Believe me it's true and it will happen again in 4 or 5 years time.
Keeping up to date
If you want further information regarding the 50MHz band, then take a look at the UK Six Metre Group (UKSMG) web site http://www.uksmg.org.uk On that site you will find details of daily activity, DXpeditions, international allocations, band plans, beacons, equipment and much, much more.
Take a look also at the RSGB VHF Contest Committee Web site http://www.rsgbcc.org/vhf as this gives details of 50MHz activity contests that are held every month.
If you have any suggestions regarding the 50MHz band plan please send an email to g4asr btinternet.com with your comments.
David Butler G4ASR, RSGB VHF Manager.
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