Using peak hold and sweeping over a range of frequencies while trying to detect such a low repetition rate signal is unlikely to yield much information. Depending on the sweep rate of the analyzer and to what it and the external source is synchronized, you may be deterministically missing the signal. You could slow the sweep speed WAY down and get some meaningful information. A better way to characterize the signal would be to set the spectrum analyzer to zero span at your receiver's center frequency with an IF bandwidth roughly equivalent to your receiver. (What you get is a fixed-frequency receiver with an oscilloscope attached to the video detector output.) You can then trigger on the signal and see what it looks like in time versus amplitude. Stu Benner EMConsulting www.emcwizard.com <http://www.emcwizard.com/>
From: [email protected] [mailto:[email protected]] On Behalf Of Derek Walton Sent: Thursday, April 19, 2007 4:56 PM To: Clif Brick Cc: IEEE EMC Discussion Group Subject: RE: Interference with a 916 MHz link Hi Clif, a SA was used to look at the band, left in peak hold mode for 5 mins... nothing showed upon the trace.... This is whats got us puzzled... Thanks, Derek. Clif Brick wrote on 4/19/2007, 3:55 PM: How about a frequency hopper passing over your frequency and making a click as it keys and then moves on? A spectrum anaylyzer might be more helpful than a receiver tuned to 916, the whole of the 902 to 928 band is full of possible sources. _____ From: [email protected] [mailto:[email protected]] On Behalf Of Derek Walton Sent: Thursday, April 19, 2007 4:34 PM To: IEEE EMC Discussion Group Subject: Interference with a 916 MHz link Hi folks, 2 questions in one day: my apologies if I'm exceeding my share of bandwidth! I'm helping a company track down what sources there may be to interfere with a short wireless data link running at 916 MHz. In our lab out of town we get almost 100% packets transmitted. In a bar in town ( were there because this is used in a bar and we were not sampling their wares, well, until we were done ), the packet success rate drops to only 60%. A SA shows little interference, but a Radio ham receiver tined to 916 MHz can pack up a strong click every second or so. The click is very loud, BUT, it does not lift the receiver squelch implying its very fast. We don't think this is local, since that signal can be received over several square miles. Anyone have suggestions as to what this could be? Thanks, -- Derek N. Walton Owner L F Research www.lfresearch.com Phone: (815) 566 5655 - --------------- ------------------------------------------------ This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Jim Bacher: [email protected] David Heald: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc -- Derek N. Walton Owner L F Research www.lfresearch.com Phone: (815) 566 5655 - --------------- ------------------------------------------------ This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Jim Bacher: [email protected] David Heald: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email ______________________________________________________________________ - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Jim Bacher: [email protected] David Heald: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
