birding-aus

Walky talkies

To: Don and Llane Hadden <>, Birding Aus <>
Subject: Walky talkies
From: Andrew Hobbs <>
Date: Mon, 07 Jan 2008 19:36:55 +0900
Hi,

I presume you are talking about UHF since these are the commonly available ones these days. We have a pair of Uniden walkie talkies 2W and they really are useful though the range can be a problem (Quoted as 7 km). The range is purely based upon output power and the landscape. The quoted range is for line of site in open air, and reasonable if using, say, across a lake in sight of each other. Vegetation cuts down on the range quite considerably, and hills etc will cut out the signal entirely unless you are lucky to get some sort of signal reflection or skip.

The power decreases by the square of the power. If the ones you used were 0.7 W (which is the lowest power generally available) then 2.8 W should give about twice the distance, assuming an arial of the same efficiency. 5W is the maximum signal allowable in these unlicensed sets. You can increase range by getting a set with a better arial which is the major advantage of units mounted in a vehicle. Some of the Uniden handsets also have matched arials which helps.

Alternatively you could try a CB 27 MHz set. These have a better range and are less line of site but tend to be very noisy, have fewer features than the UHF sets, are much less common these days, are bulkier, harder to obtain, and the arials much larger.

Cheers

Andrew


Don and Llane Hadden wrote:
Has anyone had experience of using these in the field? We live far from any mobile phone coverage and there have been times when 2 of us have been searching for birds and it would have been really handy to have been able to call them up to come over and see something special. I'm interested in the best possible range. It would be helpful if they took AA batteries but I guess not essential. I tried a fairly basic Uniden pair yesterday with a claim of up to 4km. They were marginal at 1km and useless beyond.
Any suggestions?

Don Hadden



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