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New NanoVNA possibly malfunctioning?

 

There is a better than even chance that my NanoVNA is fine and I'm the issue.? However, I started playing with my new unit this weekend and did some basic things, swept a little telescoping antenna and measured cable length.

Today, however, the measurements (pic attached, hopefully not stripped) were from a freshly calibrated NanoVNA running Dislord v1.1.00.? After a full range cal, then with 50 ohm terminator attached, vswr is bouncing all over the place.? If I try to calibrate ranges for 140-148 MHz or 420-450 MHz, vswr shows infinity.

I've handled the vna carefully and haven't yet tried characterizing filters or anything where'd I'd transmit into the NanoVNA, so there's no chance of exceeding input limits.? Can more experienced users say if it sounds there a chance I have a bad unit? Have I overlooked something beyond reset and re-cal?

Thanks very much,

Mike ab3ap

VNA_220109_160255.bmp

 

Mike,
When you calibrated the unit, did you hit the Reset softkey immediately before pressing the Calibrate softkey and then save to a specific memory slot?
If you saved to a mem slot other than 0, did you recall that slot after you turned on the unit? All Nanos default to mem slot 0 at power up.?
Can you check that the Apply box in the Calibrate menu is checked?
If everything seems ok. Redo the complete calibration again. I've seen this happen once in a while and recalibration usually fixes it.?
Cheers
Larry


On Sun., 9 Jan. 2022 at 4:41 p.m., Mike Markowski<mike.ab3ap@...> wrote: There is a better than even chance that my NanoVNA is fine and I'm the issue.? However, I started playing with my new unit this weekend and did some basic things, swept a little telescoping antenna and measured cable length.

Today, however, the measurements (pic attached, hopefully not stripped) were from a freshly calibrated NanoVNA running Dislord v1.1.00.? After a full range cal, then with 50 ohm terminator attached, vswr is bouncing all over the place.? If I try to calibrate ranges for 140-148 MHz or 420-450 MHz, vswr shows infinity.

I've handled the vna carefully and haven't yet tried characterizing filters or anything where'd I'd transmit into the NanoVNA, so there's no chance of exceeding input limits.? Can more experienced users say if it sounds there a chance I have a bad unit? Have I overlooked something beyond reset and re-cal?

Thanks very much,

Mike ab3ap
 

Thanks, Larry.? I did go through the steps you described.? (You can even see in the screenshot from before that I had recalled settings 6.)? After dinner, to be sure, though, I ran through the steps again and suddenly there are no traces at all.? All 4 are turned on and Stimulus -> Pause Sweep is not on.? I reloaded firmware (Dislord v0.69) that the unit came with but no change.? I'm thinking at this point that the unit is at fault and will send it back for a new one.? For the day or so that it worked, I love it and look forward to a replacement to put it to real use.

Thanks again,

Mike

On 1/9/22 5:47 PM, Larry Rothman wrote:


Mike,
When you calibrated the unit, did you hit the Reset softkey
immediately before pressing the Calibrate softkey and then save to a
specific memory slot?
If you saved to a mem slot other than 0, did you
recall that slot after you turned on the unit? All Nanos default to mem
slot 0 at power up.?
Can you check that the Apply box in the Calibrate
menu is checked?
If everything seems ok. Redo the complete calibration
again. I've seen this happen once in a while and recalibration usually
fixes it.?
Cheers
Larry


On Sun., 9 Jan. 2022 at 4:41 p.m., Mike
Markowski <mike.ab3ap@...> ( mike.ab3ap@... ) wrote: There
is a better than even chance that my NanoVNA is fine and I'm the issue.?
However, I started playing with my new unit this weekend and did some
basic things, swept a little telescoping antenna and measured cable
length.

Today, however, the measurements (pic attached, hopefully not
stripped) were from a freshly calibrated NanoVNA running Dislord v1.1.00.?
After a full range cal, then with 50 ohm terminator attached, vswr is
bouncing all over the place.? If I try to calibrate ranges for 140-148 MHz
or 420-450 MHz, vswr shows infinity.

I've handled the vna carefully and
haven't yet tried characterizing filters or anything where'd I'd transmit
into the NanoVNA, so there's no chance of exceeding input limits.? Can
more experienced users say if it sounds there a chance I have a bad unit?
Have I overlooked something beyond reset and re-cal?

Thanks very much,

Mike ab3ap
 

Mike,
The Config menu has a system reset (Clear config) in the Expert Settings.?
You might want to try that then go through the cal process again.?
If this is the first time you're using a Nanovna, please download and read the Absolute Beginners guide. It's in the forum files section. It will walk you through the cal sequence.?
Good luck!


On Sun., 9 Jan. 2022 at 7:24 p.m., Mike Markowski<mike.ab3ap@...> wrote: Thanks, Larry.? I did go through the steps you described.? (You can even see in the screenshot from before that I had recalled settings 6.)? After dinner, to be sure, though, I ran through the steps again and suddenly there are no traces at all.? All 4 are turned on and Stimulus -> Pause Sweep is not on.? I reloaded firmware (Dislord v0.69) that the unit came with but no change.? I'm thinking at this point that the unit is at fault and will send it back for a new one.? For the day or so that it worked, I love it and look forward to a replacement to put it to real use.

Thanks again,

Mike

On 1/9/22 5:47 PM, Larry Rothman wrote:


Mike,
When you calibrated the unit, did you hit the Reset softkey
immediately before pressing the Calibrate softkey and then save to a
specific memory slot?
If you saved to a mem slot other than 0, did you
recall that slot after you turned on the unit? All Nanos default to mem
slot 0 at power up.?
Can you check that the Apply box in the Calibrate
menu is checked?
If everything seems ok. Redo the complete calibration
again. I've seen this happen once in a while and recalibration usually
fixes it.?
Cheers
Larry
?
?
? On Sun., 9 Jan. 2022 at 4:41 p.m., Mike
Markowski <mike.ab3ap@...> ( mike.ab3ap@... ) wrote:? There
is a better than even chance that my NanoVNA is fine and I'm the issue.?
However, I started playing with my new unit this weekend and did some
basic things, swept a little telescoping antenna and measured cable
length.

Today, however, the measurements (pic attached, hopefully not
stripped) were from a freshly calibrated NanoVNA running Dislord v1.1.00.?
After a full range cal, then with 50 ohm terminator attached, vswr is
bouncing all over the place.? If I try to calibrate ranges for 140-148 MHz
or 420-450 MHz, vswr shows infinity.

I've handled the vna carefully and
haven't yet tried characterizing filters or anything where'd I'd transmit
into the NanoVNA, so there's no chance of exceeding input limits.? Can
more experienced users say if it sounds there a chance I have a bad unit?
Have I overlooked something beyond reset and re-cal?

Thanks very much,

Mike ab3ap





?





 

Thanks, Larry, that's a nicely written guide.? I didn't know of it and used the nanovna.com web page and some of Alan w2aew's well made videos.? I use RF test equipment nearly daily as part of my job, but am brand new to NanoVNA.? I hoped there were simply some quirks that needed setting right.? I had come across the Clear Config and did that as well, to no avail.? As far as I can tell now, I seem to have a failed unit.? But I'll play with it a little longer just in case.? I very much appreciate the troubleshooting ideas, thanks again!

Mike

On 1/9/22 8:57 PM, Larry Rothman wrote:


Mike,
The Config menu has a system reset (Clear config) in the Expert
Settings.?
You might want to try that then go through the cal process
again.?
If this is the first time you're using a Nanovna, please download
and read the Absolute Beginners guide. It's in the forum files section. It
will walk you through the cal sequence.?
Good luck!

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