MMIC = Monolithic Microwave Integrated Circuit Bill Ezell ---------- They said 'Windows or better' so I used Linux.
J. L. Trantham wrote: I have been reading this thread with interest since I enjoy resurrecting 'dead' instruments. Two questions though: 1. Since I have been out of the loop for many years, what is an 'MMIC'? 2. The picture suggests some corrosion or oxidation near the coax cable connection. Has this been cleaned to eliminate any chance of 'shorting' the signal to ground? Thanks, Joe -----Original Message----- From: [EMAIL PROTECTED] [[2]mailto:[EMAIL PROTECTED] Behalf Of Adrian Sent: Tuesday, July 22, 2008 6:49 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] HP58504A antenna Hi José, before trying to fix the antenna, please check if it's still working. Connect it through a bias Tee (for feeding 5 V into the antenna cable, and for decoupling DC from the analyzer) to a spectrum analyzer and use a signal generator with a short wire inserted into the output jack. Set both instruments to1575.42 MHz. Put the antenna near the signal generator (1 meter distance would be fine). You should get enough signal in the air to see if the antenna is working or not. If there is no signal, please check the source and drain voltage at the input FET (left side of your picture), Source is the left terminal, drain the upper one. Also check voltages at the output MMIC (6 pin device). Check input (lower left) and output (upper right) as well as the supply pin (lower right), plus the actual voltage that is coming in from the output coax cable, and report back. Adrian Jose Manuel schrieb: Hello all, I´d like to repair a HP58504A antenna that don´t deliver any output signal. The current is about 30 mA ( I think too high), and the transistor (unknown type) and the MMIC (uPC2749TB), seems to be with correct voltage. Does anyone have any experience or data about this antenna? I took an inside photo: [3]http://www.ea1px.es/HP58504A.jpg Can the transistor be identified by the color code? Thanks in advance, José, EA1PX _______________________________________________ time-nuts mailing list -- [EMAIL PROTECTED] To unsubscribe, go to [5]https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. _______________________________________________ time-nuts mailing list -- [EMAIL PROTECTED] To unsubscribe, go to [7]https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. _______________________________________________ time-nuts mailing list -- [EMAIL PROTECTED] To unsubscribe, go to [9]https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. References 1. mailto:[EMAIL PROTECTED] 2. mailto:[EMAIL PROTECTED] 3. http://www.ea1px.es/HP58504A.jpg 4. mailto:time-nuts@febo.com 5. https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts 6. mailto:time-nuts@febo.com 7. https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts 8. mailto:time-nuts@febo.com 9. https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.