Passive repeater using high gain antennas...

[Externet]

Hello.

Repurposing two good discarded directional antennas for 900MHz from a surplus cell tower, connected one to another; one aiming to a cellular tower and the other to a blind valley. If they are both 10dBgain; will the signal be boosted at the valley by a gain of 10X , (20dB) minus free air propagation losses ?

Cell tower<------------------------------------------------>Ant1=Ant2<--------------------->valley with marginal to poor cell service

Like 5μV at Ant1 emitting 50μV by Ant2 ?
Has any of you tried and operated such ? Details to know about ?

 

[KlausST]

Hi,

if this would be true ... you would have solved the energy problem of the world.
You "amplify" power without the use of additional energy.

No, this does not work.

Gain in dB is not an absolute value. It is a relative value.
The gain of this "directional" antenna is referenced to a non directional antenna.

Klaus

 

[vfone]

The cumulative gain of the back-to-back connected antennas (in dB) means how many dBm of power you DON'T loose when you do the retransmission from the cell tower to the valley.

 

[FvM]

"minus free air propagation losses" is the important point. The second antenna is transmitting omnidirectionally, even with directional gain, the generated field strength at some distance is much lower than the primary field (e.g. -20 to -40 dB). A passive repeater can still serve a purpose if the primary transmitter is completely blocked at the location of interest.

 

[volker@muehlhaus]

A passive repeater can still serve a purpose if the primary transmitter is completely blocked at the location of interest.

Exactly.

This "passiver repeater" technology is actually used for such cases.

Passive repeater - Wikipedia

en.wikipedia.org

Antenna Passive Repeaters For Indoor Recovery of Microwave Cellular Signals

The use of passive repeaters for mobile communications is often discarded because of the inherent losses that these systems introduce. However, the radio signal coverage of indoor areas poses a particularly complex problem in buildings with heavily reinforced concrete walls and shielded or...

www.microwavejournal.com

 

[Externet]

Thank you gentlemen.
- The mirror passive reflective repeater is not part to consider in this thread.
- Passive gain antennas interconnected back to back are the intended subject of thread.
- Recovery of signal loss after trough-wall propagation... well, consider it all outside, no buildings involved.

This "passiver repeater" technology is actually used for such cases.

A passive repeater can still serve a purpose if the primary transmitter is completely blocked at the location of interest.

That is different to :

No, this does not work.

Can you educate me ?

 

[KlausST]

Can you educate me ?

I referred to:

will the signal be boosted at the valley by a gain of 10X , (20dB) minus free air propagation losses ?

... in the meaning: you can´t increase your signal strength by +20dB

Klaus