Hi All,
I am using a Sierra 750 GPRS card
but I am connecting an external antenna to it via about 1ft of 50 ohm coax cable.
The external antenna is in an ix104 tablet computer and if you like a lot of reading the details are here :)
I have no data on the ix104 external GPRS antenna characteristics but it is certainly a lot smaller than the little rod one that comes with the 750 card.
To connect to the 750, I cut off the rod of the antenna which comes with it and solder the coax direct to the RF connector which forms the base of the antenna.
Unfortunately there are several components (capacitors and inductors) on a tiny PCB at the base of the antenna. I can't avoid damaging these when removing the plastic moulding.
The finished thing does work! The sensitivity appears comparable to e.g. a Nokia mobile phone, so I am content with it. However I am concerned about the VSWR resulting from an impedance mismatch - can it damage something?
I know about hardware/software but my RF knowledge is minimal.
Peter.
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