[RFI] Passive Cellphone Repeater?

K8RI k8ri at rogerhalstead.com
Sat Apr 16 16:06:21 PDT 2011

On 4/16/2011 5:54 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
> connection.
> 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?

My shop is much like what you are describing.  It looks like a 
conventional frame building on the outside with vinyl siding, but the 
interior is bonded barn metal. There are only two relatively small 
windows. One on the South side about 5' above the floor and a second one 
high up on the West end.  That one usually gets the air conditioner in 
the summer. If you stand in the right spot you can just see the cell 
tower (less than two miles from me) through the first window and you can 
make contact. Other places are almost impossible to connect to the 
tower.  I'm about 5 miles from the repeater and can easily work it with 
the HF from the yard, but it's a lost cause from the shop.

I've tried this on 2-meters and the 440 band with large inverted mag 
mount antennas from the ceiling, a short run of coax to another antenna 
outside.  I never did get them to work.

  Maybe others have had better luck.


Roger (K8RI)

> It seems as though that may be more reliable than the
> black box device ... if it works.

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