[RFI] Passive Cellphone Repeater?
cbrown at woods.net
Sun Apr 17 11:00:28 PDT 2011
Go spend about about $100 on a small UPS.
Passive is possible, but you would need.
Exterior and interior antennas matched to the bands used by the cell
carrier. Note, _bands_, not band. Most carriers will be running one
high, one low (example, 800/1900), but the specifics vary with
technology type (GSM v.s. CDMA) and specific carrier.
A very short run or very low loss coax (low loss at up to 2Ghz).
Ideal external antenna placement.
A _very_ strong signal.
I have seen this done several times, but they fell into 2 groups where
1) Line of sight and a stones throw from the tower with omni on roof.
2) Farther away with perfect line of sight to the tower with a well
aimed high-gain directional on roof.
As I said, get a small UPS to support the DSL modem, pico-cell, etc.
Much cheaper than the required gear for a passive.
On 4/16/11 1:54 PM, doc at kd4e.com wrote:
> It seemed to me that someone here will know about this ...
> We are in a steel building and have been using a Samsung
> Internet-GPS black box to generate a cellphone signal.
> However, whenever there is a power glitch (three times
> today due to high wind gusts in the area) we lose the
> If we go outside we can get a signal off the tower.
> SO ...
> Has anyone rigged a passive repeater using a gain-type
> outside antenna and an omnidirectional inside antenna
> with only coax connecting the two back-to-back?
> It seems as though that may be more reliable than the
> black box device ... if it works.
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