Novice question re spurs

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bconwell
Posts: 3
Joined: Sun Jul 21, 2019 12:15 am

Novice question re spurs

Post by bconwell » Sun Jul 21, 2019 12:36 am

I fired up the spectrum analysis software (latest version) on my RSP 2. I had some funny signals. In the course of tracking them down, I disconnected the antenna, and the signals persisted.

In the FM BCB band I get what look like FM signals at between -100 and -110 dBm.

More curious are 7 spurs between 250 and 375 MHz , all stronger than -90 dBm.

One spur, at 360 MHz, is at -58 dbm - even if I narrow sweep just to 359.99 to 360.01 MHz, with Ref level at -30 and range set to 100 dBm. It's an impulse-like filter, with nearby frequencies all at -120 dBm.

(A GIF screenshot is attached.)

Not what one expects with the antenna disconnected...

I tried some ferrites on the USB line, and they may have helped marginally, but spurs are still loud and clear.

Any ideas?

Tnx,

/Bill, K2PO
Portland, Oregon
Attachments
360 MHz spur, no ant.gif
360 MHz spur, no ant.gif (136.6 KiB) Viewed 1167 times
Last edited by bconwell on Thu Jan 01, 1970 12:00 am, edited 0 times in total.
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bconwell
Posts: 3
Joined: Sun Jul 21, 2019 12:15 am

Re: Novice question re spurs

Post by bconwell » Sun Jul 21, 2019 12:46 am

'Should have read

...It's an impulse-like signal...

attached is another screenshot - a 500 MHz sweep, again with no antenna connected.

/Bill, K2PO
Attachments
500 MHz sweep, no antenna.GIF
500 MHz sweep, no antenna.GIF (150.17 KiB) Viewed 1166 times
Last edited by bconwell on Thu Jan 01, 1970 12:00 am, edited 0 times in total.
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bconwell
Posts: 3
Joined: Sun Jul 21, 2019 12:15 am

Re: Novice question re spurs

Post by bconwell » Thu Jul 25, 2019 3:25 am

Do others see similar spectra with no antenna connected? Or is my device unique in this behavior?

/Bill, K2PO
Last edited by bconwell on Thu Jan 01, 1970 12:00 am, edited 0 times in total.
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