GSM-noise "buzz" issue

Andy Green andy at
Sun Sep 21 11:11:00 CEST 2008

Hash: SHA1

Somebody in the thread at some point said:
| On 9/21/08, Andy Green <andy at> wrote:
|>  This seems to be a pure frequency-dependent coupling issue, especially
|>  since Joerg tells us he can force coupling to this net by external GSM
|>  phone transmission nearby.
| I posted this before:
| (My freerunner doesn't seem to have this problem).

It requires that the network uses this "1800MHz" band at 1.7GHz uplink
to get the trouble (presumably because the victim signal only likes
17xxMHz coupling), maybe that is only difference.

| I have access to a "reasonably" well instrumented lab near Goettingen.
| ( We do remote sensing microwave spectrometers / digital backends )
| We have all the Instruments that could be usefull, I can work SMT stuff.
| I would be willing to spend a couple of hours ( or more) for gettting
| some information out of this.
| If this is in any way accessible for you, joerg?

It sounds like a great offer Joerg should take you up on.  If he doesn't
I'll be happy to.

One interesting thing would be stick a tracking generator on the GSM
antenna, put it near the headphone socket in a repeatable way, stick
spectrum analyzer probe on the victim net, and sweep them to get a
display of coupling efficiency vs frequency.

- -Andy

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