SmartSDR panorama / IQ center coupling issue

S53K

Hello FlexRadio team,

I would like to report and clarify an issue related to panorama (bandscope) behavior in SmartSDR, which becomes especially noticeable during S&P operation and larger frequency jumps.

It appears that in SmartSDR the IQ stream center frequency is rigidly bound to the panorama center (as described in the SmartSDR API documentation under Panorama Control). Because of this coupling, when a user jumps a larger frequency step (for example via Spot List or direct frequency change), the panorama is re-centered and the effective visible bandwidth becomes compressed or narrowed when returning to the original frequency area.

In practice this results in the following behavior:

• With a wide panorama view (e.g. ~1 kHz or more) the display behaves correctly while tuning locally.
• After jumping ~50–100 kHz away and then returning, the panorama no longer restores the original width and appears “shrunk”, making weak-signal search less effective.
• This is reproducible both locally and in remote operation (Maestro, SmartSDR, loging programs,,… ).

From a user perspective, this coupling is problematic because the panorama view should be independent of the IQ center or at least preserve its previous scale and width when returning to the same frequency range.

This is particularly relevant for contest and S&P operation, where operators frequently jump between spots and rely on a stable, wide panorama view to detect weak or nearby signals.

I understand this is an architectural design choice, but it would be highly beneficial if:

• the panorama width/scale could be preserved across frequency jumps, or
• the IQ center could be decoupled from the panorama center, or
• an option could be provided to lock the panorama behavior.

Thank you for considering this feedback.

73
Simon / S53K / NA3AA / CQ3A