Re: Am I in the right track ?
Yes, you're on the right track. However, I'd strongly recomment you place
several appropriate clamp-on ferrites on your feedline right where it exits
the assembly. Also place a few at the VNA,
By
W0LEV
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#39570
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Re: Am I in the right track ?
you should albsoutely calibrate on cable end and use one as short as it is practical (just a few inches would be best!!)
only THEN you have exact values to type into simsmith .. then calculate parts
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Siegfried Jackstien
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#39569
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Re: Am I in the right track ?
John,
Thanks once again for the precious advices. As I’ve put the antenna exactly as I t has been manufactured, could I simply populate the matching network instead of stretching the spirals ?
By
Nico
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#39568
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Re: Am I in the right track ?
Nicolas,
Your results actually look pretty good. An SWR of 2.4:1 represents a loss of only 17%.
Small changes in the spacing of the turns on your antenna should enable you to put the minimum SWR at
By
John Gord
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#39567
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Re: testing non-50 ohm filters was Re: [nanovna-users] NanoVNA port renormalization
Another jig in this post….
/g/nanovna-users/message/20848
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Roger Need
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#39566
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Re: testing non-50 ohm filters was Re: [nanovna-users] NanoVNA port renormalization
Clifton,
My test jigs and other members were discussed several years ago in this topic. There are 125 messages and lots of good info.
/g/nanovna-users/message/20809
By
Roger Need
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#39565
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Re: Am I in the right track ?
Once again,
Thanks to all of you for your inputs. Poorly translated from french, I would say that I did not know in what type of gearbox I was going to put my finger in !
Well, I ran some other
By
Nico
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#39564
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Re: testing non-50 ohm filters was Re: [nanovna-users] NanoVNA port renormalization
Can you show a closeup picture of the TEST JIG for your NanoVNA please.
________________________________
Sent: Sunday, February 23, 2025 5:01 PM
To: [email protected]
Subject: Re: testing
By
CLIFTON HEAD
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#39563
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Re: testing non-50 ohm filters was Re: [nanovna-users] NanoVNA port renormalization
Can you show a closeup picture of the TEST JIG for your NanoVNA please.
________________________________
Sent: Sunday, February 23, 2025 1:26 PM
To: [email protected]
Subject: Re: testing non-50
By
CLIFTON HEAD
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#39562
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Re: Am I in the right track ?
as shorfter the cable as better your setup
dg9bfc sigi
Am 23.02.2025 um 20:32 schrieb Nico via groups.io:
By
Siegfried Jackstien
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#39561
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Re: Am I in the right track ?
Nico,
You don't necessarily need more connectors.
You could calibrate at the end of your RG174 cable by detaching it from your board, then using a small 50 ohm chip capacitor, an open circuit, and a
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John Gord
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#39560
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Re: Am I in the right track ?
When you use the edelay feature in a NanoVNA to move the reference plane from the SMA connector to a distant point you really need to have a short cable so the attenuation is minimal. This is not
By
Roger Need
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#39559
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Re: Am I in the right track ?
These are very interesting points, thank you very much for that.
I was questioning myself wondering if my technique was appropriate. Thanks again for confirming it can be improved.
I will follow
By
Nico
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#39558
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Re: testing non-50 ohm filters was Re: [nanovna-users] NanoVNA port renormalization
I own an MFJ259, a RigExpert AA-55 and a NanoVNA H & H4. The MFJ is the poorest performer of the bunch and not really useful for measuring resistance or reactance to any degree of accuracy. The
By
Roger Need
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#39557
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Re: testing non-50 ohm filters was Re: [nanovna-users] NanoVNA port renormalization
Hi Jim
MFJ company says that MFJ259 antenna analyser becomes inaccurate when measuring reactances below 7 Ohm or above 650 Ohm, i am really impressed with the good S21 responses you have even with
By
Team-SIM SIM-Mode
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#39556
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Re: Am I in the right track ?
May be it's a new version in program, that you must enter the velocity factor as .66 and not in percent. Your measured data are ok, but the 2m RG174 has a loss of 2dB @ 900 Mhz. So the real mismatch
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schweppe
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#39555
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Re: Am I in the right track ?
it?s close ... but you will get much better results if you use a short cable ... and calibrate at the end of that cable
dg9bfc sigi
Am 23.02.2025 um 04:46 schrieb Nico via groups.io:
By
Siegfried Jackstien
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#39554
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Am I in the right track ?
Hi,
Is my setup ok ? Is there any monstrous mistakes in my montage ? I'm quite new to the nanoVNA. Well, I am totally new on VNAs themselves. I did not know their exitance 2 months ago ! Well, I
By
Nico
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#39553
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Re: Adapting the LiteVNA for SAR?
Use S21 mode with an amplifier.
People have been using VNAs as radars for years.
The NanoVNA just makes it easier.
Dealing with the big first reflection is tricky. One way is to use a separate
By
Jim Lux
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#39552
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Re: testing non-50 ohm filters was Re: [nanovna-users] NanoVNA port renormalization
You have noted the shortcomings of* ANY* VNA, including those from the "big
boys" at $$$$$. Nothing new, here.
Yes, the VNA deals with impedances. Frequency analysis best be
accomplished using a
By
W0LEV
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#39551
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