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Feature request


Martin Kratoska, OK1 2020/10/18 10:08

Hello,

very nice addition would be a set of predefined ham radio bands and
simultaneous watching of SWR and impedance similar to EU1KY analyzer
style (oic attached). Would be possible to include these enhancements
into future firmware releases?

73,
Martin, OK1RR

Peter KA6Z 2020/10/18 19:14

Excellent suggestion. This would be a terrific addition.
Peter KA6Z
On Sunday, October 18, 2020, 01:08:37 AM PDT, Martin Kratoska, OK1RR <martin@ok1rr.com> wrote:

Hello,

very nice addition would be a set of predefined ham radio bands and
simultaneous watching of SWR and impedance similar to EU1KY analyzer
style (oic attached). Would be possible to include these enhancements
into future firmware releases?

73,
Martin, OK1RR

Toad Laurence 2020/10/18 12:37

Er, yes, maybe. But relatively few users of these devices are radio amateurs ( I am).

Would it not be more useful to have a logarithmic frequency sweep option on the x axis? This could show up all the amateur bands from 3mhz to 30mhz on a log sweep (the maximum cover for most multiband aerials) giving the same resolution for fractional frequency change.

The log sweep could be useful to other users too.

Steve L. G7PSZ

Siegfried Jackstien 2020/10/19 04:23

who else if not ham radio operator buys a vna v2 ??

a professional (say commercial) user does spent several k bucks for
professional test gear and would not buy such a "semi-professional" and
cheap unit

dg9bfc sigi


Am 18.10.2020 um 19:37 schrieb Toad Laurence via groups.io:

ok1vaw 2020/10/19 00:04

I can imagine a sort of field engineers of small private companies (like internet providers or radio net engineers), who are not in a situation to spent several k bucks. They can count and buy such a simple unit for testing or evaluation purposes to have one in case of need.
On the other hand, for any production, where fast response is needed such a filter or antenna adjustment in comparison to any commercial scalar system or SA with tracking it is not very usable due to the slow speed.
73s, OK1VAW, Vojtech.

ok1vaw 2020/10/19 00:07

Perfect idea, I agree Martin.
73, OK1VAW

Josh A 2020/10/19 19:09

No. In my opinion, the original suggestion is far more useful than a
wideband log sweep.

Josh, VK4JNA

On Mon, 19 Oct 2020 at 1:25 pm, Toad Laurence via groups.io <g7psz=
icloud.com@groups.io> wrote:

Martin Kratoska, OK1 2020/10/19 12:45

Incorrect interpretation, Steve. Although I mentioned "ham radio bands"
it should be read as "as set of user predefined bands". Actually this is
not related exactly to ham radio, it is related to any user who needs a
VERY SMALL TOOL to make field adjustments of antennas, matching devices
etc. Logarithmic frequency sweep option is NOT the right choice, I am
not interested on the whole range but on predefined bands...

Martin, OK1RR

Dne 18. 10. 20 v 21:37 Toad Laurence via groups.io napsal(a):

Stephen Laurence 2020/10/19 04:20

Well, the log sweep could also be a useful addition. As well as calculating the actual sample frequencies during the sweep, the reference grid would also have to be redrawn, but it should not take up too much firmware space.

As an alternative, the log sweep could be added to the pc based server programs ( nanosaver etc) where size of the program is less important.

Steve L

Siegfried Jackstien 2020/10/19 13:12

Am 19.10.2020 um 11:20 schrieb Stephen Laurence:
> Well, the log sweep could also be a useful addition. As well as
> calculating the actual sample frequencies during the sweep, the
> reference grid would also have to be redrawn, but it should not take
> up too much firmware space.
>
> As an alternative, the log sweep could be added to the pc based server
> programs ( nanosaver etc) where size of the program is less important.

in nanovna saver under sweep settings you will find log sweep

greetz sigi dg9bfc

Jim Lux 2020/10/19 06:47

On 10/18/20 9:23 PM, Siegfried Jackstien wrote:
> who else if not ham radio operator buys a vna v2 ??
>
> a professional (say commercial) user does spent several k bucks for
> professional test gear and would not buy such a "semi-professional" and
> cheap unit
>
> dg9bfc sigi
>

quite a few professional engineers (in the sense of being paid, not
necessarily licensed) have bought NanoVNAs and similar small units.

a) in these days of COVID-19 telework, something small that you can use
at home is handy
b) It's sort of like a DMM - it doesn't take up much room on the bench,
and you can use it for checkout of a breadboard.
c) All those "fieldfox" portable applications (similar to the breadboard
testing) can sometimes be met by the NanoVNA, and it's a heck of a lot
cheaper nor does it attract attention from the institutional calibration lab

While it would seem that it is a "good investment" for a company to
provide the optimum test equipment to produce maximum efficiency of
their engineers - it doesn't always happen that way in real life. Labor
comes out of a different budget than equipment if nothing else.




>
> Am 18.10.2020 um 19:37 schrieb Toad Laurence via groups.io:
>
>> Er, yes, maybe. But relatively few users of these devices are radio
>> amateurs ( I am).
>>
>> Would it not be more useful to have a logarithmic frequency sweep
>> option on the x axis? This could show up all the amateur bands from
>> 3mhz to 30mhz on a log sweep (the maximum cover for most multiband
>> aerials) giving the same resolution for fractional frequency change.

Interesting point you raise - historically spectrum analyzers and VNAs
have a had linear scales - it's more convenient with analog circuitry,
if nothing else.

The challenge with a log sweep is getting useful information with
limited number of points, and you get much finer resolution at low
frequencies than at high ones (I've been doing log sweeps in wideband
antenna models) Let's say you use 5% steps in frequency, at 1MHz, the
steps are 50kHz, at 30 MHz, the steps are 1.5 MHz.

It is true that for a lot of phenomena (tuned circuits), ratios are more
relevant than absolute differences, so log scales are a natural
presentation.

JohnSG 2020/10/19 14:27

+1 Another vote for log frequency scales.

Also, I'm a working engineer who bought this for work. Of course I would like a full-blown VNA like the Agilent I had at my last job.

Cheers,
John

Peter KA6Z 2020/10/20 02:14

Both log and linear frequency have their uses but the applications are different. Log makes sense for characterizing devices, as say unity gain (fT) for bipolar transistors but not sure how that can be employed with the nanoVNA...
But for characterizing antennas for radio work linear plots make more sense. 
But I think Martin's point was to be able to have several ranges on the display at once. Currently, we can see say 3MHz-to-30MHz along one scale, or well 3MHz-to-3GHz.  But if you are interested only in certain segments of frequencies within these wide ranges, it's hard to eyeball then intelligibly when the display just gives the whole 3MHz-3GHz spectrum at once on a 3.2" display (or ok soon 4" and 7" etc...).
And hams are not the only ones who look at discrete spectrum for antenna analysis.
Peter KA6Z

On Monday, October 19, 2020, 04:20:38 AM PDT, Stephen Laurence <gaslaurence@gmail.com> wrote:

Well, the log sweep could also be a useful addition. As well as calculating the actual sample frequencies during the sweep, the reference grid would also have to be redrawn, but it should not take up too much firmware space.

As an alternative, the log sweep could be added to the pc based server programs ( nanosaver etc) where size of the program is less important.

Steve L
---------------------------------------------------Incorrect interpretation, Steve. Although I mentioned "ham radio bands"
it should be read as "as set of user predefined bands". Actually this is
not related exactly to ham radio, it is related to any user who needs a
VERY SMALL TOOL to make field adjustments of antennas, matching devices
etc. Logarithmic frequency sweep option is NOT the right choice, I am
not interested on the whole range but on predefined bands...

Martin, OK1RR

Dne 18. 10. 20 v 21:37 Toad Laurence via groups.io napsal(a):

Stefan 2020/11/17 11:17

Up to 8 user defined frequency segments will be great.

---
Stefan / AF6SA
www.af6sa.com ( http://www.af6sa.com )

Rob O 2020/11/19 10:07

The idea of log frequency sweeps has been tackled by someone (ae6ty), i.e. there is a PR, but it does not appear to have been integrated.
https://github.com/ttrftech/NanoVNA/pull/129

This might provide some hints for anyone wanting to have a go. I recall that a key difference/requirement of defined seqments or log sweeping is to keep the measurement frequency with the results and not rely on knowing a start freq, step and no of points.

I think both log sweeps and pre-defined segments would be useful.
I find that as soon as bandwidth / centre frequency > ~ 5 or 10 % a linear sweep isnt helpful.

Rob
M5RAO

emece67s 2020/12/07 04:15

I do also find highly desirable to have a log frequency sweep.

As an aside, I'm a ham, but use the nanoVNA as a useful tool at work as it fits in my desk and also at home.

Regards.

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