[hpsdr] Hermes VNA - Beta test code

Tue Sep 25 06:49:00 PDT 2012

Hi Kjell,

Thanks for the feedback and pleased to hear the VNA code appears to be 
working.

You can reduce the SWR and RL ranges by checking the  Auto Scale button. 
This
will automatically use the max and min values of the data set to scale the 
graphs.

As per the User Guide, the numbers in the Results section relate to the last 
frequency
in the scan or the measurement frequency if only a Start frequency is 
specified.

OK - regarding using lines on the Smith Chart - I'll have a look at that, it 
was simple to do
on the graphs but  not so sure how difficult it will be on the Smith Chart.

When you first ran the code - with Hermes connected and powered on as per 
the User Guide - then the first thing
that is done is a Discovery on all the Network adapters on your PC.  This 
should have found
your Hermes board.  As per the User Guide you can also enter the IP address 
of  the Network
adapter that you will be using to connect to Hermes and it will 
automatically use that address first.

After the code has successfully located the adapter the details are saved in 
VNA.ini and it will try
that adapter IP address first each time the code is run.

The attenuator idea using J1  is fine and that is the way I suggested in the 
User Guide.

If you have any measurement problems then save the results in a Measure File 
and email to me
- no need to send the associated Calibration File - that way I can use the 
data in the file to trace
through the code and see what's going on.

Not sure about the scan stopping - not seen that during development - so may 
need a few more folks
testing to track that one down.

73 Phil....VK6APH

-----Original Message----- 
From: Kjell Karlsen
Sent: Tuesday, September 25, 2012 4:37 PM
To: hpsdr at lists.openhpsdr.org
Subject: Re: [hpsdr] Hermes VNA - Beta test code

***** High Performance Software Defined Radio Discussion List *****

Hi Phil.

Thanks for the VNA code!

I have tested it using a home brew Directional Coupler that is constructed
for use up to 1,5 GHz. It seems to be working OK. I did not get connection
to Hermes without entering the IP address and Hermes MAC that I found in
PowerSDR when connected there.

When I measure, I observed that sometimes during the scan,(1-60 MHz) the
scanning stops at about 1/3 and there is a message (after the line Hermes
Vector Network Analyser -V1.0.0 ):does not answer or not answering
(Depending of the translation from Norwegian!) It then fills the
progression bar and shows a nearly flat SWR line. If I then start another
scan, the scan is normal and the shown SWR is OK.

With this wide scan and connecting an antenna, the SWR scale is from 0 to
100 and the RL from 0 to-100 dB. I would like to manually decrease the
maximum SWR to let say 20 and the RL to 30 dB.

In the Smith chart I would like to have a line drawn between the measuring
points. I reckon this is not yet implemented as the Display selection is
grey?

I do not understand the numbers below Results. Are they for a specific
frequency or what?

I am looking for a simple method to connect the Directional coupler to
Hermes when it is installed together with Apollo. I have installed J1 and
use an attenuator (R17=39 Ohm, R18= 150 Ohm) of around 6 dB. I am not sure
it is wise to have the RX connected to Apollo while the coupler is in use.

This looks very promising!

73, Kjell

På Mon, 24 Sep 2012 13:23:21 +0200, skrev Phil Harman <phil at pharman.org>:

> ***** High Performance Software Defined Radio Discussion List *****
>
> To Beta Hermes board users.
>
> There is a Beta release of the Hermes VNA code available for testing.
>
> The code, VNA.exe, is in SVN here:
>
> < http://svn.tapr.org/repos_sdr_hpsdr/trunk/Hermes/VNA >
>
> and a draft User Guide here:
>
> < http://svn.tapr.org/repos_sdr_hpsdr/trunk/Hermes/Documentation/ >
>
> You will need to load Hermes with V1.7 of the FPGA code which is 
> available
> under Downloads on the openHPSDR.org web site. V1.8 will be available
> shortly, which will be the production code installed on the TAPR boards,
> so alternatively use that when available.
>
> Thanks to Joe, K5SO, for his work on getting V1.8 ready for TAPR's 
> production run.
>
> You will also need .NET V4.0 to be installed on your PC in order to run
> the VNA code.
>
> The User Guide is intended to provide sufficient information for you to
> use Hermes in VNA mode.  It's not intended as a detailed introduction to 
> a
> VNA but please report any glaring omissions.
>
> My thanks to Bill, KD5TFD, for programming assistance and a special 
> thanks
> to George, K9TRV, for his extensive code reviews and C# mentoring.
>
> George has also produced an installer for the PC code which we will use
> once the Beta testing is complete.
>
> Please send any bug reports and/or user guide changes directly to me and
> any bouquets or feature requests via the reflector :)
>
> 73 Phil....VK6APH
>
>
>
>
>
>
>
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