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Got it. Thanks. The 800 MHz ch now shows going to 800 MHz. It has
another issue though. Spikes are all over and go all the way to the top of
the screen when no load is attached. Looks OK with 50 Ohm load.

Jim K.

Hi SPACE OPQA,

Thanks for the info. Where is the August Version?

Thanks,

Jim K.

Hi Mike,

Thanks very much for that information. The 800 MHz aa version of the
firmware corrected the problem. The 800 MHz ch version did not. In fact
the 880 MHz ch version still goes out to 900 MHz. I got the firmware from

Is there a newer version somewhere?

Thanks,

Jim K.

Resending from website as it didn't seem to go through as a message. Also
my pasted table from Excel lost formatting so I tried to fix it to be more
readable.


I just did some very simple resistance and SWR measurements using a HP
8753ES with 85046A, resistance was measured using a calibrated Agilent
34401A in 4 wire mode.

I did a very basic one port 3 point cal using a Anritsu OSL which is
specified to over 3 GHz.

I took measurements at 900 MHz.

Load R ohms SWR SWR notes
OSL 50.052 1.001 Flat
Cheap BNC 51.104 1.908 Sloping up with freq
Nano load 49.044 1.019 Flat
Narda 12.4 GHz 49.536 1.018 Flat
Tiny SMA 50.787 1.009 Flat


I am guessing there is some significant reactive component in the BNC
terminator. All three of the SMA loads showed a flat SWR with frequency so
I'm thinking they all have a minimal reactive component.

The difference in resistances while keeping SWR low was a bit of a
surprise to me. The load that came with the Nano is over an ohm off of the
load I used to calibrate yet the SWR remains at a low 1.019. Why is this?
I did the math and surprisingly this is indeed correct, per calculation the
SWR should be 1.021 vs my measured 1.019. I'd say this is darn close
seeing one measurement is DC resistance and the other is at 900 MHz.

So my conclusion is that SWR is not a sensitive number to see resistance
differences.

Once I read some of the references cited I can do some more advanced
measurements.

Peter

Tuck

I am not sure if you are misunderstanding (I don't think so) or simply miss-stating the concept. A load, any load, does not have an inherent return loss. It only has a return loss as measured relative to a reference. Typically the reference is understood to be 50 ohms. Minute differences in the resistance and reactance of the reference load can lead to huge differences in return loss, especially when you are talking RL on the order of 40 or more dB.

The numbers that I have shown are not the result of design or calibration routine errors but, in fact, differences in the characteristics of the loads themselves.

As a verification I have re-run the tests I made prior with the nanoVNA on my spectrum analyzer/tracking generator/RF bridge combination. It has an inherent dynamic range of 100 dB at a resolution bandwidth of 1 kHz..... 130 dB if I engage the preamp. I again used each of the three loads as a reference on the bridge with the other two measured for return loss in succession. Here is a comparison table of the nanoVNA as compared to the professional setup.

As you can see, the results are remarkably close. Especially at return losses less than 40 dB. I have no concerns whatsoever about relying on the nanoVNA results for hobby and home lab use.

Warren Allgyer
WA8TOD

The screen is touch sensitive. Tap it to bring up the home display menu.
Select “stimulus”. That’s where you enter the frequencies and other
information. You can also push down on the jog wheel to activate the menu and
then scroll and select.

Go to “files” on the groups.io website and download the PDF titled “Menu
Map”. It will show you how to navigate the menu structure.

Have fun,

Larry

On Aug 6, 2019, at 3:01 PM, Stuart Landau via Groups.Io

<stuartl73@...> wrote:

Certainly reasonable questions. I would add entering frequencies and other

entries. I am new to the NanoVNA but not network analysis.

Stuart K6YAZ

On Aug 6, 2019, at 11:56 AM, Larry Rothman <ac293@...> wrote:

Hi Bob, welcome to the group.
There are a number of references in the FILES and WIKI sections.
You can also do a search of key words from the many posts that have good

info.

Note - there are several versions of the NanoVNA, the best being one of the

black units.

Although this unit will never compare to a lab quality VNA, it does perform

remarkably well for its simple design.

Read up on the lengthy discussions regarding calibration to get the best

results from your new 'toy'.

I have posted a number of references here:
/g/nanovna-users/wiki/External-links
/g/nanovna-users/files/Miscellaneous

Regards,
Larry VE3LRI

On Tue, Aug 6, 2019 at 02:26 PM, Bob Kozlarek wrote:

After discovering the Nanovna I decided to order one. A short introductory
discussion formed on AMFONE.NET, which mentioned this group, so I decided
to join. I’ve been reading through the posts and already learned a lot.

It

sounds like most of you are part of an advanced user group. I’m

wondering

if anyone can suggest any entry-level on-line resources which would
summarize what should / must be done when you first receive the Nanovna?
I’m wondering about matters such as does the firmware need to be updated
and from where it would be obtained, is calibrating required each time you
use it, and the matter about extra shielding be added to some units? I
apologize for asking these entry level questions in what appears to be a
very advanced user group, but I’ve always believed that the only dumb
questions are those we don’t ask.

Bob, WA2SQQ

Yes, I did reload firmware with nanoVNA_900ch_20190722.dfu

Forgot to mention that earlier. The above firmware did help on one I got
earlier with a lot lower spike but did not help much on this one.

Thanks for the help though.

Jim K.

On Aug 6, 2019, at 3:01 PM, Stuart Landau via Groups.Io <stuartl73@...> wrote:

Certainly reasonable questions. I would add entering frequencies and other entries. I am new to the NanoVNA but not network analysis.
Stuart K6YAZ

On Aug 6, 2019, at 11:56 AM, Larry Rothman <ac293@...> wrote:

Hi Bob, welcome to the group.
There are a number of references in the FILES and WIKI sections.
You can also do a search of key words from the many posts that have good info.
Note - there are several versions of the NanoVNA, the best being one of the black units.

Although this unit will never compare to a lab quality VNA, it does perform remarkably well for its simple design.
Read up on the lengthy discussions regarding calibration to get the best results from your new 'toy'.

I have posted a number of references here:
/g/nanovna-users/wiki/External-links
/g/nanovna-users/files/Miscellaneous

Regards,
Larry VE3LRI

On Tue, Aug 6, 2019 at 02:26 PM, Bob Kozlarek wrote:

After discovering the Nanovna I decided to order one. A short introductory
discussion formed on AMFONE.NET, which mentioned this group, so I decided
to join. I’ve been reading through the posts and already learned a lot. It
sounds like most of you are part of an advanced user group. I’m wondering
if anyone can suggest any entry-level on-line resources which would
summarize what should / must be done when you first receive the Nanovna?
I’m wondering about matters such as does the firmware need to be updated
and from where it would be obtained, is calibrating required each time you
use it, and the matter about extra shielding be added to some units? I
apologize for asking these entry level questions in what appears to be a
very advanced user group, but I’ve always believed that the only dumb
questions are those we don’t ask.

Bob, WA2SQQ

Yes, I did reload firmware with nanoVNA_900ch_20190722.dfu

Forgot to mention that earlier. The above firmware did help on one I got
earlier with a lot lower spike but did not help much on this one.

Thanks for the help though.

Jim K.

On Aug 6, 2019, at 11:56 AM, Larry Rothman <ac293@...> wrote:

Hi Bob, welcome to the group.
There are a number of references in the FILES and WIKI sections.
You can also do a search of key words from the many posts that have good info.
Note - there are several versions of the NanoVNA, the best being one of the black units.

Although this unit will never compare to a lab quality VNA, it does perform remarkably well for its simple design.
Read up on the lengthy discussions regarding calibration to get the best results from your new 'toy'.

I have posted a number of references here:
/g/nanovna-users/wiki/External-links
/g/nanovna-users/files/Miscellaneous

Regards,
Larry VE3LRI

On Tue, Aug 6, 2019 at 02:26 PM, Bob Kozlarek wrote:

After discovering the Nanovna I decided to order one. A short introductory
discussion formed on AMFONE.NET, which mentioned this group, so I decided
to join. I’ve been reading through the posts and already learned a lot. It
sounds like most of you are part of an advanced user group. I’m wondering
if anyone can suggest any entry-level on-line resources which would
summarize what should / must be done when you first receive the Nanovna?
I’m wondering about matters such as does the firmware need to be updated
and from where it would be obtained, is calibrating required each time you
use it, and the matter about extra shielding be added to some units? I
apologize for asking these entry level questions in what appears to be a
very advanced user group, but I’ve always believed that the only dumb
questions are those we don’t ask.

Bob, WA2SQQ

I just received a NanoVna from Amazon (AURSINC). It is a black one with
the shields.

The receive side shows a signal at 300 MHz with input connected to dummy
load. The signal is so strong that it shows at -6 dB from the top of the
screen. I have two others that are from other sources and they show a very
small signal at around 300 MHz that does not interfere with measurements.

The interference on this one is so bad that it is unusable.

Any idea what this could be and is it something I can fix without
returning it to Amazon? Tried calibration and it did not help.

Any help greatly appreciated.

Jim K.