Flex 5000 - What is this odd panafall image?

Lionel

The image of the panafall shows many narrow signals, narrow spaced on the right side of the screen. They exist on the left but not as clearly.  These do not move when changing frequency, rather they stay in exactly the same place on the panafall.  This oddity seems to exist on all ham bands with varying amplitude.

I can get rid of this by re-installing the PSDR software. I am using the T11 version.  If I go back to the baseline PSDR 2.7.2, reinstall as if the 5000 is being installed for the first time and reinstall T11 (any iteration seems to do the same) the problem is always corrected. 

Does anyone have a clue?  Is this a dB that is being corrupted? If this was an analog rx I'd say some signal(s) were getting into the IF.  The way that I correct it feels like dB.

It's a little annoying and I know the correction, I'd just like to understand why these "apparent" signals appear.  Is this an indication in any way shape or form of an approaching hardware issue. 

https://1drv.ms/w/s!AloqAzRI-q1xibUG1MTgMi5Sn_caiQ

Darren G7DAZ

Hi Lionel,

yeah i too have the same "anomalies".....it's 1 that seems to repeat itself equally (zoom out and you'll see the repetition)...it's definately the same "signal/spike/etc" as when i closely watch it in the panafall they have the exact same breaks/gaps in them when they are falling down in the waterfall; not only that but if i start with both receivers running then they are "repeated" below (exactly underneath each other) in the other panafall almost harmonic (identical spacing as well,almost as if they were spurs) wise and even if both bands are different i,e, RX1 80m and RX2 40m.

I too was thinking that it was something like local interference and decided to live with it, but seeing now as others are having the same issues i'm curious as to what it may be/reason.

Are they "spurs" by any chance ? ....Click-tuning onto them has no effect as they move back to the LHS of where i just clicked. :-( ....so i know they ain't genuine signals as such.

73 de G7DAZ (Darren)

Lionel

Darrin, Spur reduction didn't help.    Like you I was convinced it was some interference.  I have seen it appear and then disappear after awhile without my doing anything, so maybe interference I thought, but if that were true you could tune it across the screen.  You can't.   I've expanded it also and see the same as you.  I only have one rx in mine.

It's interesting the way it shows up on your RX1 and RX2.  Hmmm. A puzzle.

We can't be the only two users seeing this. 

Darren G7DAZ

Hi again Lionel,

after much searching and a bit of experimentation it looks like i (we) have DDS spurs :-(  ...i get more of them with my SR button(s) OFF and less with the SR button(s) activated; they also "shift"....this link is what gave me my answer

http://forums.flexradio.com/Topic3197-40-1.aspx#bm3199

i suppose i'll just have to live with them, ah well.

73 de G7DAZ (DarrEn)

Lionel

Hi Darren,

I agree with poster K0VM on the link insofar as spurs go.  What I'm seeing, and what I believe you are seeing, is more like a comb effect (made up effect) with many spurs close together covering maybe 50-60 kHz of the panafall.   For me they appear apparently at random days/times/bands and sometimes go away with my intervention.  They always go away if I reload PSDR. 

Correcting by reloading PSDR seems to strongly point at it being Flex hardware or PSDR itself.  The counter argument is that it seems to correct itself with my intervention leading me to believe it is external somehow getting into the Flex hardware, maybe at the IF. 

These seem mutually exclusive.  But there are numerous unintentional radiators around and maybe I have a wall wart somewhere in the house putting out trash at the IF frequency sporadically.  

Coincidences happen and maybe my reloading PSDR has coincided with the external radiator stopping the interference.  It's a weak conclusion.

You're right, it is one of those things we will have to live with and it's not a big deal. 

On the other hand I'm behaving like the house cat and can't let go of the curiosity.  I just know there's a mouse in here someplace....

Tim - W4TME

Correcting by reloading PSDR seems to strongly point at it being Flex hardware or PSDR itself.

Most likely the Firewire interface (card).  Try running at a lower sampling rate and see if the issue improves.  If it does, then I'd swap out the fiewire cable first and then think about the Firewire card.

Lionel

Thanks for the idea.   When thinking about hardware I completely glossed over the Firewire interface. 

I'll see what happens when it reappears.

Lionel

The odd panafall image that started this thread had gone away for the last week.  It just now returned, on 20m and 17m not on any other ham bands.   Changing sampling rate had no effect.   After pushing every button on PSDR I found that turning the preamp on and then off and it went away.   It has not come back, preamp is off.  

Now this is weird.  Maybe a coincidence.  The preamp on/off is the only thing that I've seen work, other than a complete reinstall of PSDR.   

Darren, try the preamp the next time you see this on panafall. 

Darren G7DAZ

Hi Lionel,

turning my pre-amp/s on/off made no difference at my end :-(  ....still the same little 3 "spurs"  (5 max) regardless of where i am on the band, I might try and upload a picture to show said "beasties".

I have done a visual measurement and they are near as **** 64kHz apart...does this tell anyone what it may be ??

I've ordered a Texas Instruements based pci "e" firewire-card, but it won't arrive until after the Xmas holidays.....hopefully Tim may have hit the nail on the head; failing that it's a new PC come January.

73 de G7DAZ (Darren)

Tim - W4TME

If you toggle SR (spur reduction) and the spurs move, then they are DDS artifacts.  SR doesn't actually remove spurs, it moves them so they are out of your RX passband.

Darren G7DAZ

Yeah a few of the almost invisible ones "do" shift left/right when i turn the SR button on/off; ... i agree they must be as you said DDS artifacts, but the main "3" that are the issue of the OP are still there (in my case) and don't move at all with the SR button....all i can do now is swap my firewire card (when it arrives) and go from there...fingers crossed they'll disappear :-)

Tim - W4TME

Without a picture to see the main 3 spurs you are describling, it is hard to determine what they may be. Can you post a screen shot of it?

Darren G7DAZ

Hi Tim & Lionel...as requested here is the picture showing the 3 nasties that don't appear to be spurs. Notice that they are directly under each other (regardless of band). If i move the band-scope quickly with the mouse backwards and forwards then the lines in the waterfall have "breaks/gaps" in them (waterfall) and all 3 are identical; this tells me that whatever it is there's only ONE and it's repeated 3 times.

The other very very faint lines (not all of them) are definate "spurs" and as Tim as said they move left/right etc. etc. therefore DDS artifacts....i'm not quite sure what the other ines/peaks are; i assume it's band noise etc.....the line/s at 3.752 and 3.697 are a ham signals so ignore them lol.

Turning off Receiver Antenna socket 1 & 2 makes no difference FWIW; still the same 3 peaks.

73 de G7DAZ (Darren)

p.s. sorry if the picture turns out small as i can't find a "preview before posting" button; unless it's the "pre" icon below.

EDIT: hopefully the link will show a bigger picture
http://i29.photobucket.com/albums/c286/Jeckyll_n_Snyde/Stuff%202%20share/3%20nasties_zpsahdkfk86.jpg

Tim - W4TME

If you change the sampling rate of the Radio (firewire interface) to a lower value, do the spurs still show up in the same relative places on the panafall display?

Darren G7DAZ

Hi Tim, yes and no...when i change to a lower rate (96kHz) there's only 2 visible...and only 1 visible at 48kHz sample rate; i just have to move l/r now as the visual bandwidth is smaller...they seem to be at set frequncies (could have sworn they shifted left to right when i panned) and almost 63kHz apart...this got me to thinking...i turned off the antenna's and they dissapeared...all that was left was a very few faint ones that did shift with the S/R button.....so in a nutshell it looks like it might actually be something in my vacinity that maybe radiating....just strange that if it is something radiating then you'd think the pulse/peak would appear different as you travel up/down the band; it doesn't, they're the same amplitude and at 62/63 kHz spacings, getting neither weaker nor stronger as you scan the band...it is moving though; compared to last nights screenshot it/they have moved 4kHz up the band....Firewire card maybe ??? + temperature changes etc. ??? ....catch 22 i can't unplug the firewire card to confirm lol.

Just annoying that i'll have to use the +TNF if i was listening to a station on a frequency where said "nasty-peak" was sat.

Darren.

Darren G7DAZ

so in a nutshell it looks like it might actually be something in my vacinity that maybe radiating.

As per my previous quote above it turns out it was something in my vacinity....as I've found it :-)

turns out the only thing i couldn't turn off was the 2nd monitor that i use for PSDR....i discovered it by accident after re-awking the monitors from time-out-standby; i moved the mouse, the monitors fired back up but the 3 beasties MOVED sideways a tad before settling back down...ah ha says i to myself, i knew it had to be the monitors or my PC.

Cut a long story short after swapping monitors i isolated the interference to my 17" DGM (4:3 ratio) monitor; my 19" DGM (4:3 ratio) monitor was just fine...so the POS will serve me for a while longer until i replace both for modern day widescreen jobbies.

Lionel i hope you find the root of your "signals"...fingers crossed it could be something as simple as your monitor.

Good luck with your fault finding and many many thanks to all for their input.

73 de G7DAZ (Darren)