November 26, 2011
“We have poor Vodafone coverage – will your SMS unit work on the Telecom XT network?”
The short answer to this question is no – SMS devices compatible with the New Zealand Telecom XT network are very hard to source and expensive if you can.
However, all is not lost. If you can get useable coverage outside your house on the Vodafone network – and particularly if you can get good coverage in an elevated location such as on the roof of your house, then there should be no problem making our system work on your property.
In these situations we would supply the SMS unit in a watertight outdoor enclosure. This is supplied with a 15-20m long 6-core alarm cable and incorporates a mounting bracket similar to that of a small television antenna (U-Bolt/V-Block arrangement).
Why can’t the SMS unit stay indoors and we connect an outdoor antenna to it instead? The answer to this is: You can but there will be little advantage and several disadvantages to this approach.
Outdoor cellular antennas are expensive and specialized. Signal losses in the coaxial cable connecting to an outdoor antenna mean only short lengths are recommended or you will lose some of the gain from the antenna itself – this limits the possible mounting locations of the SMS unit.
Coaxial cable at cellular frequencies tends to be very thick and rigid making it difficult to run, whereas thinner, flexible alarm cable can be run much greater distances with ease and is more forgiving if there are kinks in the cable.
In summary, the outdoor SMS is the best solution providing you have first checked for reasonable signal strength at the intended mounting location. The SMS unit has a superior antenna than the one inside your phone, which is designed more for aesthetics than function – this means it will automatically have better coverage than your phone.
If you require more clarification please contact us.