If you are looking to drive a direct response from consumers, such as calling a phone line to order your product or arrange a sales meeting, it is worth remembering that some marketers question whether radio can be effectively used in this way.

But there are others who are more than happy to use it, as Mike Berry, managing partner of integrated marketing agency Spirit DPM observes.  "It's not immediately obvious as a response medium.  Lots of people listen to radio in the car, for example, and won't respond at that point.  But if you can put a memorable website address or 800 number in your ad, then it will work.  They'll call when they get to work, or when they get home.  If you've got a complex URL, or a non-catchy phone number, then forget it."

Another of radio's strengths, its promoters say, lies in the relationship between a station or an individual presenter and the audience.  Why this relationship becomes so strong is difficult to explain.  Perhaps it is because radio encourages listeners to create their own images to go with whatever they are listening to.  Used properly, radio can be an excellent method of targeting a defined audience and engaging their attention, arguably in a way that TV cannot do.

Radio Works' Michael Charnley-Heaton believes much of the power of radio lies in this intimacy.  He says, "Radio is the ideal medium for small businesses, as local radio listeners have a very close relationship with their favorite station and advertisers can benefit from this."

That feeling of intimacy can be heightened by tailoring executions to fit in with the time of day the ads are to be broadcast.  RAB's Sampson says, "Radio changes its mood depending on the time of day, it's a very different beast in the morning to what it is in the evening."

Making a number of different ads may sound like extra work or expense, but radio experts argue that it makes economic sense, particularily when compared with the costs of TV production and airtime.  Radio advertising is relatively cheap to produce, much cheaper to broadcast, and also takes far less time to make and get on air."

FLEXIBILITY

According to Michael Charnley-Heaton, "a big strength of radio for smaller advertisers is the ability to change your copy quickly and regularly without incurring huge costs.  The production cost for a TV campaign could buy you a national radio campaign for a month."

That means you can adapt your advertising quickly and cost-effectively to take advantage of changing conditions.  A drinks retailer could put out an 'instant' ad on the radio in response to changes in duty in the budget, or a manufacturer of fans could take advantage of a sudden change in the weather.

One final caveat is that radio advertising should never be seen as a cheap alternative to TV.  It is a very different medium, with its own strengths and weaknesses, which have to be properly understood before any campaign is undertaken.  As Ed Harwood warns, "Never let yourself be pushed into radio advertising because that's all you can afford - save your precious marketing budget.  And never be tempted to run just the bare minimum.  Wait until you can run a strong campaign."

And don't bother trying a test-campaign, he says, "You don't need to test radio advertising.  Thousands of business spend money on radio advertising for one simple reason - it works!"