Panadapter goes blank when pre-amp enabled

Grant Kesselring

Mike-VA3MW

Hi Your receive antenna is set to the to RX A. Is that the antenna you wish to use? Mike

Gary NC3Z

Grant Kesselring

Hi Mike.  Yes, ANT1, ANT2 and RX A are all valid antenna selections for me.  The panadapter issue is present regardless of antenna input selection.

Grant Kesselring

Gary,
Great idea!  I think your suggestion is on the right track.  Typically, I have the minimum amplitude on the panadapter adjusted so the noise floor is positioned near the bottom of the screen.  For example, on 6m with pre-amp off my noise floor is -130dB so I have adjusted the vertical axis slider so the minimum amplitude is approximately -140dB.  Now, if I switch to +8dB pre-amp selection, the panadapter goes completely blank as previously reported.  But,  if I adjust the minimum amplitude all the way down to -170dB, I can still see just the peaks of strong stations.  Anything selection greater than +8dB pre-amp and it is totally blank.

As you say, the pre-amp does indeed cause the spectrum floor to go down.  However, in my case it appears to go down so much that it renders the panadapter useless.  Is this the way it is intended to work?  Anybody else see the same thing?

KC2QMA_John

Grant Kesselring

John, thanks for the comment.  Even though the panadapter noise floor is dropping below the panadapter minimum when the pre-amp is enabled, the waterfall display is fine.  This leads me to believe there isn't any physical problem with the radio (ie, bad RF preamp or loose connection).  It just appears that something is throwing the panadapter scale way off when pre-amp is on.

Dudley WA5QPZ

Grant, Try clicking on the vertical scale on the right side and move up, so you will expose more of the scale, this is most likely where your horizontal panadapter is hiding. Dudley WA5QPZ

Grant Kesselring

Hi Dudley, the panadapter noise floor with no pre-amp is -130dB for me right now.  Everything displays fine.  But, with just +8dB pre-amp, the noise floor on the panadapter display goes below -170dB.  All I can see is the peaks of signals (see picture).  I can't slide the vertical scale low enough to see the noise floor.  Also, note that the waterfall display is working just fine.

Cal N3CAL

Michael N3LI

N8SDR

click the  arrows on the right side of the scale were it currently list -100 -110 -120 etc. drop that downward. and you should be good. if it doesn't move, then try doing a factory reset , dont forget to save your profiles before doing so, then if that works you can import them back in.


Bill -VA3WTB

Looks like he is moving the wrong scale. It is the one above the water fall.

Mike-VA3MW

Another question.  What happens if you select ANT1 as the receiving antenna?  Does it work as you would expect?

Grant Kesselring

Hello, yes I am able to click the up/down arrows in the top right corner of the panadapter to increase/decrease the maximum amplitude.  I am also able to adjust where the noise floor is positioned within the panadapter by clicking/dragging the vertical axis.  All that works fine.  What does not seem to work correctly for me is the amount the noise floor shifts with different pre-amp settings.

Bill -VA3WTB

What happened when you did a factory reset to the radio?

Grant Kesselring

Grant Kesselring

Hi Cal, thanks for the suggestion.  I tried zooming out the waterfall to wide, but the noise floor was unchanged.

Grant Kesselring

Hi Michael, I tried turning off the spotting software, but that did not make any difference.  I think I will try doing a factory reset of the radio this evening.  I'll report back with results.

Grant Kesselring

I'll give that a try, Bill.  Thanks for the suggestion.

Grant Kesselring

I just tried my experiment again, this time on 30m.  Now, the panadapter noise floor is shifting below -180dB when the PreAmp is +16dB, +24dB or 32dB.  This is happening with ANT1, ANT2 and RX A.