I/Q imbalance error problem for all users?

n6gnn6gn
in Configuration and Operation

Is it not the case that a single user selecting I/Q extension and performing "IQ balance" when there is something other than noise in the passband say can cause a serious noise floor measurement error for all users?

I think we've come across a case where in modes where the selected BW includes band center that a misadjusted balance setting can result in an 'invisible' term at DC that would be similar to LO leakage. In this case, does that imbalance not apply to all users and also persist across power cycles?

A receiver that Rob had at KPH appeared to have a very high noise floor in wide BW's that crossed Fcenter that caused him to think there was a HW problem. Upon examination the noise floor and delivered SNR in USB was normal and 20 dB better than in, say, IQ or AM modes where the IF BW crossed center. The anomaly was repaired by performing the IQ balance correctly and that Kiwi appears to now be 'fixed'.

I've never even used this tool before because there was no need but it would seem that this balance correction should only be available to admin and not to any regular user.

Do I understand this wrong?

Glenn n6gn

Comments

  • jksjks

    Checking..

  • jksjks

    I believe it's working correctly. Although the yellow IQ bal and Fcal buttons will appear for regular user connections, as soon as you press them the admin password entry panel will appear before allowing you to go any further.

    From a local network connection of course you're automatically given admin rights. I checked kphsdr.com:8072/73 and got the admin password panel in all cases.

    I also double checked that malicious use of the Kiwi API couldn't cause a non-authenticated balance or cal to occur.

    But if you find a repeatable test case that fails, by all means, please let me know (preferably via the support email).

  • n6gnn6gn

    Ah! It hadn't occurred to me that a local user had higher priority than a wide area one and therefore special permissions. This points to either Rob or one his designate admins to having caused the problem.

    But of course his secret is safe with us, we'll never tell ! 😁

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