-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Somebody in the thread at some point said:
|> You would think it also depends on output power from our RF section; it |> might be worth trying with "piece of wire" antenna to force it to use |> highest transmit power if otherwise your base station is close. | | Using "piece of wire" might serve well to spoil SWR of transmitter, thus | reducing antenna gain. So it's correct BTS will advice MT to increase ... I dunno if that is the case or not, but I do know the GSM system on the board will act differently at power using $WIRE rather than the intended antenna, and we can get a clue about what goes on by rattling as many doorhandles as possible. It certainly means something that the buzz still comes happily or put another way we would be very interested if the buzz stopped coming with $WIRE. |> If it isn't that you are using low power, that's pretty interesting, it |> couples at 1.7GHz but not 1.8 - 1.9GHz then. It seems something we are |> missing is frequency response of the radiated coupling to the victim net. | That's why I asked for it some mails ago, so we had an idea which frequencies | are the ones GTA02 is sensitive to. | Though the result wouldn't probably change anything about proposed fix, which | is to place beads/EMI-filters there on JK4401, and please do it as soon as | possible. I looked at this last night, but my setup is too crap to get a sensible result. All I have around is some old scope probes terminating in BNC, so I cut one off and used that cable from the tracking generator (it's like 2V p-p) first for radiated coupling I placed the insulated core up the inside of the headset jack and looked on MICBIAS with the spectrum analyser via another scope probe, then secondly I placed the tracking generator output directly on pin 4 of the jack and looked at MICBIAS and surrounding components. But presumably because these scope probes and cables were only rated for 100MHz, just kinking the wire or moving the leads around totally changed the response far more than what I was measuring. I dunno if I should terminate the lead to 50R, via a cap, no idea how to improve it at the moment. I think it will be very interesting to meet Uwe and his guys. - -Andy -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (GNU/Linux) Comment: Using GnuPG with Fedora - http://enigmail.mozdev.org iEYEARECAAYFAkjXaXcACgkQOjLpvpq7dMqP8gCgkJJmybvDRoSsdpdtx14x5ylR reUAn2RZf1pzQSJp6aDwoW8agr+MDe3u =8KyS -----END PGP SIGNATURE----- _______________________________________________ hardware mailing list [email protected] http://lists.openmoko.org/mailman/listinfo/hardware
