Exploring the 70-centimeter band for amateur radio

The 70-centimeter band is a great place for amateur radio enthusiasts to explore and experiment with new technologies. This band offers a range of frequencies from 440 to 470 MHz.

One of the benefits of the 70-centimeter band is its relatively short wavelength, which allows for more precise targeting and better penetration of obstacles. This makes it ideal for applications like local communication and emergency services.

In the US, the 70-centimeter band is allocated for amateur radio use, with a frequency range of 420-450 MHz reserved for simplex operation.

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The 70-centimeter band is a unique frequency that lies between the 2-meter and 33-centimeter bands. Its propagation characteristics are influenced by frequency, with higher frequencies above 200 MHz reducing building penetration and smaller obstacles potentially blocking or reflecting the signal.

As you increase in frequency, you'll notice a lower noise floor, making it easier to overcome interference in urban environments. This can be a significant advantage when operating in densely populated areas.

Tropospheric enhancement is a common propagation mode on the 432MHz UHF band, with events occurring more frequently than on lower frequencies. However, this band tends to be less active compared to 144MHz or other popular bands.

When the 432MHz band does open up, you can expect to make contact with dozens of stations at considerable distances away from the UK, including Eastern Europe and Scandinavia.

The 70-centimeter band is a popular frequency range for amateur radio enthusiasts. Plus or minus 5 MHz is a common repeater frequency offset in the 70 cm band in the USA.

A repeater is essentially an amplifier that boosts weak signals, allowing them to travel farther and reach more people. This is especially useful for amateur radio operators who want to communicate with others over longer distances.

Repeater input channels can be a bit tricky to set up, but understanding the basics can make a big difference. A common repeater frequency offset is a split of 1.6 MHz, which is used elsewhere in the world.

Here are some common repeater input channels for the 70-centimeter band:

Keep in mind that these are just general guidelines, and the specific frequency offsets used may vary depending on your location and the repeater network you're using.

The 70MHz UK band plan is based on the International Amateur Radio Union (IARU) Region 1 band plan.

The philosophy behind band planning is to assign 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.

Users must take into account the bandwidth of their sidebands when selecting an operating frequency, as this determines the maximum spectral width of all emissions recommended in a sub-band.

The mode indicates the modulation methods allowed in a segment, such as telegraphy, telephony, or machine generated mode, which includes transmissions relying fully on computer processing like FSK441 or PSK31.

The ‘Usage’ column indicates the main usage of a sub-band or segment, which contains meeting/calling frequencies agreed upon for the convenience of VHF operators practicing specific modes of communication.

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The 70-centimeter band has two main frequency ranges that are worth noting. The first is 70.100 – 70.250MHz, where you'll find narrowband modes like CW, SSB, and MGM, with a maximum bandwidth of 2.7 kHz.

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This range is often used for Morse code, telephony, and machine-generated mode activity, such as PSK31 and JT6M. You'll usually find most CW and SSB activity around 70.200MHz.

The second frequency range is 432.500 – 432.994MHz, which is allocated to any mode with a maximum bandwidth of 25 kHz. This range is great for a mixture of telephony and other modes like facsimile, radio-teletype, and slow-scan television.

This sub-band area of the 70MHz band is allocated to all modes with channelised operation, where both telephony and digital modes exist. Narrowband FM (NBFM) channels have a 12.5 kHz spacing.

You'll find FM telephony, packet radio, RTTY, and internet gateways in this section of the band. The UK usage column indicates that the majority of channels are used by digital modes, but that doesn't mean you can't use them for FM telephony.

It's essential to listen on these channels to ascertain locally whether they are in use or not. If you hear no other traffic, you may conduct your contact on any channel you wish to use.

The 70.294-70.500MHz band has a unique allocation, allowing for a mix of telephony and digital modes. This is a great opportunity to experiment with different modes and find what works best for you.

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The 430MHz band is a treasure trove for amateur radio enthusiasts, and one of the most interesting segments is the non-channelised area from 432.500 to 432.994MHz.

This area is allocated to any mode with a maximum bandwidth of 25 kHz, which means you can find a mixture of telephony and other modes like facsimile, radio-teletype, and slow-scan television.

You can use amplitude modulation (AM) here, but be considerate of adjacent channel activity when selecting your operating frequency.

In this segment, you'll find a diverse range of signals, all operating within the 25 kHz bandwidth limit.

In some countries, like the UK, you have permanent access to the 70MHz band, which offers 500kHz of bandwidth.

Radio amateurs in these countries can enjoy a more consistent and stable frequency allocation.

Not all countries have the same level of access, and some may have fragmented band plans.

Individual band plans can be very different from one country to another.

In the UK, the Radio Society of Great Britain has a main site with information on the 70MHz band.

This is an important resource for radio amateurs looking to get started or learn more about the band.

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DX opportunities abound on the 70MHz band, with many countries having permanent and temporary allocations. This makes it an ideal distance from the UK for propagation modes like aurora, meteor scatter, and Sporadic-E.

Some countries, like South Africa, have had a 70MHz allocation for years, making it possible to work with stations on FM, CW, and SSB using converted private mobile radio sets.

The 9000km path between the UK and South Africa is particularly interesting, as both ends lie at the extremity of the trans-equatorial zones. This makes a contact over the TEP path possible around Sun Spot maximum.

Possible openings between the UK and South Africa will probably occur during the month of October.

The 430-440 MHz spectrum is also allocated to the Amateur Satellite Service, making it a great spot to hear CW, FM, SSB, or MGM signals from low-earth orbiting amateur satellites.