Mar 18

WRITTEN BY: Peter Martin
Friday, March 18, 2011 

Passive Repeaters.

If you are in a rural area with a weak signal this is probably not going to work for you.We are not offering this as a general solution but if you have a good level of technical understanding of the problem and the way antennas work, you might want to have a try.

Before you try a passive repeater you need to set up your external antenna using a direct connection, or  a connection via a cradle or a passive patch lead, to your mobile phone or datacard. 
This is necessary to line up your antenna and measure if you have enough signal for the passive antenna to work.

Q. What is a passive repeater
A If you are in an area with very good coverage but cannot receive a signal inside a building because it cannot penetrate the roof and walls, the problem can often be solved by using a passive repeater. A passive repeater is just two antennas connected with a cable. The first antenna picks up the signal, passes it down the cable and the second antenna re-transmits it. Then the transmitted signal from the mobile phone or wireless data card follows the reverse path.





Q. What are active repeaters?
A. Anything that adds energy to either the received or transmitted signal can be classed as an active repeater. This is done using amplifiers and requires a power source -either from the mains or by DC.

Active  repeaters are naturally much more effective than passive repeaters; BUT,  unfortunately to stay within the law you need the permission of the spectrum holder to transmit on their frequency bands and we are not allowed to sell this type of equipment, nor are you legally allowed to use it without authorisation from Telstra, Optus etc.  (Note that this does not apply to the public 2.45Ghz 801.11b,g  band which is used for your home wireless network)

Q What sort of range will a passive repeater give?
A. That really depends on how strong a signal is present outside the building. You'd need to have a good LOS to a local Basestation for this to pick up sufficient signal.Passive repeaters can work but don't expect that a combination of two antenna is going to be a magic solution and give you full coverage throughout your house!

Q What about passive antennas for the Optus network 900 and 2100 MHz bands?
A  You'll need a pair of antennas which also covers both bands.

The recommended outside antenna  a Triangle multiband antenna, as shown in th elink and the photo below,  Yagi 14088A

TRIANGLE ANTENNA ON CART

The recommended inside antenna  is a panel antenna  as shown in the link and the photo below
ANTENNA ON CART

A possible broadband passive antenna to cover all Australian Cellular Bands at 850, 900, 1800, 1900 and 2100 MHz





Q What sort of antennas will I need for Telstra Next G?
A  For Telstra next G who mainly use 850MHz you will need for outside the building : high gain antenna such as:
 
ANTENNA ON CART

or

LASER ANTENNA

This antenna is tuned for Telstra's Next G Network at 850MHz

and inside the building smaller antenna such as:

or a CEILING ANTENNA



Q What sort of cable will I need?
A It depends on the choice of antennas. Its probably easier if you just let us know which antennas you want to use and the length of cable you need and we can then advise.

Q. How do I know which way to point the external antenna?
A. Its better to have it directly connected to a  phone or wireless data card  using a patch cable when doing this.

Customer Feedback:
" Initally it all didn't look too good until I found a tower line of sight, a couple of kilometres away behind a tree. Other towers are nearer, but behind hills.  Elsewhere on the premises we get full signal on all GSM phones except for one blackspot due to concrete walls. The repeater now gives at least two 'bars' signal on mobiles within around a ten metre radius of the indoor antenna.That makes for a very happy Production Manager who now no longer has to leave his desk to take/make mobile calls."  Nick Kelly IT Manager Lovitt Technologies Australia Note: You really need a good strong signal outside your building to make a passive repeater work. Otherwise you'll need a direct connection to your phone. Its always a good idea when ordering a passive repeater to also make sure that you have the right cables for a direct connection to your phone, as a fall back option , in case the outside signal level is not strong enough for the passive repeater to work properly.  Mobile phones,  and wireless data modems, like a TV set, work much better when there is a direct connection  to the antenna.

Other related links:

Telstra/Bigpond and other 850/900 MHz services

Optus (inc Exetel Optus), 3, Virgin, Vodafone, and Services Using both the 900 and 2100MHz bands

2100MHz Only(Virgin,Optus)

Using Splitters with Mobile Phone / Datacard Wireless Antennas