On 7 feb, 16:35, "EpsilonRho" wrote:
My mother lives in a area where the cell-phone signal is very weak.
Typically I can get only one mark on the phone field strength meter. That
forces me to go outside the house in order to have a reasonable chance of
completing a call (of course only if the weather permits). I have only basic
understanding of antennas, so I am asking this forum if the following idea
is feasible.

I am planning to build (or buy) a 850 MHz Yagi antenna (14 dB gain) to be
installed on the outside and pointing towards the signal strongest
direction. The boosted signal would be transmitted through a balun and a low
loss 75 ohm coax cable to the inside of the house terminating to a 1/4
wavelength 75 ohm antenna stub. Is this feasible? Could I get perhaps a 10bB
signal boost inside the house by means of this arrangement?

TIA
Gene

Regarding passive repeater,

Only when you have a very strong signal outside (that means your house
must be a very good shield), your suggested arrangement will work. The
problem is in the path between your handheld and the quarter wave
antenna inside your house.

Just 3 ft away from your quarter wave antenna the propagation loss is
about 30 dB (at 850 MHz). Assuming about 3 dB cable loss, the overall
loss (with respect to the handheld outside) will be about 20 dB. So
this arrangement may give improvement only, within one meter of the
quarter wave antanna in case of a building loss of more then 26 dB.

Probably you need a repeater system or connect your handset to the
cable directly (via RF coupling or other means).

Best Regards,

Wim
PA3DJS