Intermodulation on RX888

[micked]

Test setup, RX888 at 30m with a narrowband 500Khz bandpass filter inline, also without the filter the problem is present.

This is the spectrum on wspr waterfall, when using the bw setting of 2, 4 and 8 there is some inter modulation from what it looks like FT8, when changing to bw 1, 16, 32Mhz the interference disappear, as I have a very narrow band bp filter inline the interference should only be possible from the nearby ft8 on the same band.


/Mikael

[jdow]

Might I suggest a similar sort of picture of SDRC showing the settings for the RX888? You could try inserting some attenuation on the RX888 input.

{^_^}

[micked]

Hi, yes, it might be so simple as inserting a 10db attenuatior, I run the radio at 0 (no attenuation) but the problem is still present using the internal 10 and 20db attenuatior but then the signals dropped so much it was unusable at those settings, pic of settings, there is no settings in the RX888 then just bw and attenuation which are now known So, Im fine with using the radio at 16Mhz bw , thats where I use it the most anyway!

[jdow]

I surrender. You know more what I need to help you than I do. So if I may be so ugly as to suggest you pound sand, do it. (Yes, I got up on the wrong side of the bed today.)

{+_+}

[micked]

So, further tests, the problem is present also in the 16 and 32Mhz bw settings, I have not tested 1Mhz, I did test to inserted an external 10db attenuation, problem still there, BUT when I changed the setting from standard usb to Wide-U @ 10Khz the problem disappear, I will let it run on 16Mhz BW and 10Khz audio bw while Im of to work.

[micked]

Ok, so the Bw setting is not important, the the problem is present at any bw but is easily fixed by klicking between USB to Wide-U, easy fix for now