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Re: Need help matching my DIY antenna using a NanoVNA

 

For more bandwidth, build a 2D (flat) bow tie antenna.
Make it vertically polarized for best performance.

On Thursday, December 8, 2022, 05:51:17 AM EST, William tunna <willtunna@...> wrote:

Hi all,

I hope this is okay to post in this group as I'm new here. I've built a dipole antenna using copper tape and a RG58 coaxial for my kit aircraft as per some plans I have and I wanted to test it to see if it matched with my radio specifications of having a VSWR of under 2.5. The frequency range for the air band is 117MHz to 136MHz and I am wondering how I can flatten my SWR curve I'm seeing on the NanoVNA. As you can see from the pictures, I'm achieving an SWR of 1.57 at the midway frequency around 127MHz but at the lower frequencies it goes all the way up to 4.2 SWR.

Things that I have tried -

- I've added length to the ground strip, which makes the SWR closer to 1 in the lower frequencies but increases the SWR in the higher frequencies.
- I've taken away from the antenna strip and the SWR goes down in the higher frequencies but makes it a lot worse in the lower frequencies.

I started with a ground strip of 540mm and an antenna strip of 545mm, and now I'm at 560mm on the ground strip and 485mm on the antenna strip.

What's the best way to go about making this better? (Also, if I've made no sense, it's because I have no idea what I'm really doing...)
SUBTRACTING COAX #applications

Phil, WF3W
 

Hello all XMAS-gift hopefuls,

Is there a way/method/technique for subtracting coax length from readings, as can be done in Rig-Expert's ANTScope, sftwr?

73
Phil, WF3W
Re: Need help matching my DIY antenna using a NanoVNA

 

117 to 136MHz is a wide band, proportionally wider than the amateur 80 meter band, which is also difficult to cover with a single antenna. One method of broadbanding a dipole antenna is to make the antenna elements larger in diameter or width in your case. You should be able to easily double the width of your copper strips. Taper them down at the feedpoint.
You may be able to add tuning elements at the feedpoint to help improve the match but you may have to accept a poor VSWR at the band edges.
I suspect that most aircraft antennae are probably equally poor in this respect. I also believe that the radios are built to take it.
Do not forget that feedline loss will mask a poor antenna match, so the radio will not see as bad a load. Check at the end of the actual cable run, which is what the radio will be seeing; you might see a very different situation.
Look at some of the literature regarding broadbanding HF antennas; the techniques are applicable to VHF and scale with frequency.
73, Don N2VGU
Re: Need help matching my DIY antenna using a NanoVNA

 

Hello Bill,

You have explained your problem quite well.
Presumably the leading edge of the vertical stabiliser on your aircraft will be faired with fabric, fibreglass or timber.
If it will be faired in aluminium, this antenna will not work and you will need to go to an external 1/4 wave whip as used on the majority of light aircraft.
This would also require a metallic "ground plane" to be fitted to the fuselage, but let's not get ahead of ourselves for a moment.

A couple of questions:
1) does the coaxial cable shield connect directly to one half of the dipole and the centre connect directly to the other half?
Note: I am guessing the design has the coaxial cable shield (braid) connected to the copper strip on the top of the fuselage.
2) are there any ferrite cylinders fitted to the coaxial cable near the antenna?


Either way, here are a couple of things to try.
1) do as Ken suggested and adjust both halves of the antenna equally and adjust for a minimum at around the centre frequency of 126MHz.
Does this satisfy your requirements?

If not:
2) does the copper tape have conductive adhesive?
If "YES" run another length of tape beside both of the existing pieces, overlapping the edges slightly.

If "NO" still run another length of tape as above, but you will need to solder the joint along its length.
You can just spot it every inch or so.

Reason: this makes the antenna electrical bandwidth wider which should drop the VSWR at the band edges.
You may have to fiddle the lengths again slightly to keep the minimum centred around 126MHz. (or there abouts, don't stress too much)
BTW, if the tape does not have conductive adhesive, you will need to spot solder any pieces you add to the ends.
NOTE: if you need to buy more copper tape, just buy a roll of wider tape and replace the existing pieces.

Hopefully your problem is solved now.

But if not, try fitting 3 or 4 type 43 ferrite cylinders to the coaxial cable near the antenna connections.
These are commonly sold through electronics stores for EMI (electrical interference) mitigation.
You want them with a hole just big enough for the coaxial cable to fit through and around 25mm (1") long. They will be about 12-14mm in outside diameter.
Ask for help at your friendly electronics store. You want something roughly equivalent to a Fair-rite Type 43 ferrite mix.
You can fix them in place with adhesive to stop them moving around.

Reason: this will act as a Choke Balun to "balance" your (unbalanced) coaxial cable to the balanced feedpoint at the centre of the antenna.

I have deliberately made this a bit wordy to help you understand what you are doing. You can Google any of the key words you don't understand.

Hope this helps.

Cheers...Bob VK2ZRE

On 8/12/2022 10:48 pm, Ken Goodings VE3MVN, VE0SH wrote:
Each half of your dipole should be around 60 cm. They should be both equal
in length for your center frequency of 126 mhz
Trim each end by the same amount on each test.
Half wave dipole length calc in inches for vhf is 5905¡Â f or 5905¡Â126=
48.86 inches
Each half is 23.4 inches or 59.5 cm

On Thu., Dec. 8, 2022, 6:51 a.m. William tunna, <willtunna@...> wrote:

Hi all,

I hope this is okay to post in this group as I'm new here. I've built a
dipole antenna using copper tape and a RG58 coaxial for my kit aircraft as
per some plans I have and I wanted to test it to see if it matched with my
radio specifications of having a VSWR of under 2.5. The frequency range for
the air band is 117MHz to 136MHz and I am wondering how I can flatten my
SWR curve I'm seeing on the NanoVNA. As you can see from the pictures, I'm
achieving an SWR of 1.57 at the midway frequency around 127MHz but at the
lower frequencies it goes all the way up to 4.2 SWR.

Things that I have tried -

- I've added length to the ground strip, which makes the SWR closer to 1
in the lower frequencies but increases the SWR in the higher frequencies.
- I've taken away from the antenna strip and the SWR goes down in the
higher frequencies but makes it a lot worse in the lower frequencies.

I started with a ground strip of 540mm and an antenna strip of 545mm, and
now I'm at 560mm on the ground strip and 485mm on the antenna strip.

What's the best way to go about making this better? (Also, if I've made no
sense, it's because I have no idea what I'm really doing...)
Re: Need help matching my DIY antenna using a NanoVNA

 

Should have a balun at the feedpoint. The OEM dipole in my Cessna did. This reduces/eliminates the effect of the feedline and rest of the radio and wiring in the aircraft.
Nano V2 on the blink.......

[email protected]
 

Hello all. Have had this VNA for a while and never used it much. Plugged it in to charge after a couple of years. Did well. Went thru all the usual calibration steps as always did in the past. Problem: No trace activity at all. I formatted it on the Smith chart and the trace is all over everywhere. I mean like a piece of broken glass, not the usual EKG type pattern. SWR format, straight line in the middle of the screen. No movement at all when connected to any antenna. Unit does not seem to recognize any input. It does seem to calibrate, but then again how would I know? Right. Before I post photos of the screen activity, I am in hope that someone can at least give me an idea as to the neighborhood of a problem.... No problem if it is junk as I bought this as an impulse buy and quickly found it to be a novelty item for me. Very frail to use in field.
Re-visited the use as I was going to give it to a new radio gadget friend. Might be garbage worthy...
Thanks and appreciate any feedback.
Tim? W4ADC
Re: Need help matching my DIY antenna using a NanoVNA

 

Each half of your dipole should be around 60 cm. They should be both equal
in length for your center frequency of 126 mhz
Trim each end by the same amount on each test.
Half wave dipole length calc in inches for vhf is 5905¡Â f or 5905¡Â126=
48.86 inches
Each half is 23.4 inches or 59.5 cm

On Thu., Dec. 8, 2022, 6:51 a.m. William tunna, <willtunna@...> wrote:

Hi all,

I hope this is okay to post in this group as I'm new here. I've built a
dipole antenna using copper tape and a RG58 coaxial for my kit aircraft as
per some plans I have and I wanted to test it to see if it matched with my
radio specifications of having a VSWR of under 2.5. The frequency range for
the air band is 117MHz to 136MHz and I am wondering how I can flatten my
SWR curve I'm seeing on the NanoVNA. As you can see from the pictures, I'm
achieving an SWR of 1.57 at the midway frequency around 127MHz but at the
lower frequencies it goes all the way up to 4.2 SWR.

Things that I have tried -

- I've added length to the ground strip, which makes the SWR closer to 1
in the lower frequencies but increases the SWR in the higher frequencies.
- I've taken away from the antenna strip and the SWR goes down in the
higher frequencies but makes it a lot worse in the lower frequencies.

I started with a ground strip of 540mm and an antenna strip of 545mm, and
now I'm at 560mm on the ground strip and 485mm on the antenna strip.

What's the best way to go about making this better? (Also, if I've made no
sense, it's because I have no idea what I'm really doing...)
Need help matching my DIY antenna using a NanoVNA

 

Hi all,

I hope this is okay to post in this group as I'm new here. I've built a dipole antenna using copper tape and a RG58 coaxial for my kit aircraft as per some plans I have and I wanted to test it to see if it matched with my radio specifications of having a VSWR of under 2.5. The frequency range for the air band is 117MHz to 136MHz and I am wondering how I can flatten my SWR curve I'm seeing on the NanoVNA. As you can see from the pictures, I'm achieving an SWR of 1.57 at the midway frequency around 127MHz but at the lower frequencies it goes all the way up to 4.2 SWR.

Things that I have tried -

- I've added length to the ground strip, which makes the SWR closer to 1 in the lower frequencies but increases the SWR in the higher frequencies.
- I've taken away from the antenna strip and the SWR goes down in the higher frequencies but makes it a lot worse in the lower frequencies.

I started with a ground strip of 540mm and an antenna strip of 545mm, and now I'm at 560mm on the ground strip and 485mm on the antenna strip.

What's the best way to go about making this better? (Also, if I've made no sense, it's because I have no idea what I'm really doing...)

IMG_0532.jpg
IMG_0536.jpg

Re: Firmware for the NanaVNA-H4

 

On Wed, Dec 7, 2022 at 10:09 PM, Paul - W1BIU wrote:


Version: 1.1.01
Build Time: Dec 30, 2021 - 00:16:53

And, if there is a later version, where do I find it?
This is where the magic of DiSlord happens, either you get his source code and build it yourself (currently 1.2.16):


Or you get my -H and -H4 binaries (choose one of bin, dfu, or hex formats - whatever you need), which I compile from DiSlord's current GitHub source code:


-H Download links:




-H4 Download links:




Martin
Re: Firmware for the NanaVNA-H4

 

Hi,Have a look overhere: latest version from? ISlord is 1.2.073sEgbert PD0EZL
-------- Oorspronkelijk bericht --------Van: Paul - W1BIU <paul.w1biu@...> Datum: 07-12-22 22:10 (GMT+01:00) Aan: [email protected] Onderwerp: [nanovna-users] Firmware for the NanaVNA-H4 What is the Latest Firmware for the NanaVNA-H4I'm currently running:based on DisLord @edy555 ... sourceVersion: 1.1.01Build Time: Dec 30, 2021 - 00:16:53And, if there is a later version, where do I find it?73Paul W1BIUU
Firmware for the NanaVNA-H4

 

What is the Latest Firmware for the NanaVNA-H4

I'm currently running:
based on DisLord @edy555 ... source
Version: 1.1.01
Build Time: Dec 30, 2021 - 00:16:53

And, if there is a later version, where do I find it?

73

Paul
W1BIUU
Re: Part II Nano VNA - the more advanced stuff

 

Thanks Barry!

73!
Costin, YO8RCD

?n mie., 7 dec. 2022 la 19:41, Barry K3EUI <k3euibarry@...> a scris:

What can I do with a Nano VNA?




If you are up to it - here is Part II of my ¡°Nano VNA¡± talk to the
MidAtlantic ARC in May 2021 at their monthly Zoom meeting. The first 30
minutes or so is their Business Meeting - so skip ahead.

Part I Nano VNA The Basics was the previous month, April 2021 - almost
no math.
Looking at the Nano VNA like one more ¡°tool¡± in your tool box.

Part II (a look under the hood) I was not afraid to get deeper into the
weeds - logs and return loss in dB and Smith Charts plotting resistance and
reactance in POLAR form.

I did make TWO errors - see if you can spot them.

The Nano VNA device is rather remarkable. A fantastic tool for about $100
now.
Mine is almost three years old now - an original from Amazon with the SMA
connectors.
Take the time to learn what a VNA can measure and compute.
Again I used Windows Nano VNA SAVER software (free) to produce these
graphs.

Best wishes
De k3eui Barry
K3euiBarry - at - gmail.com
Part II Nano VNA - the more advanced stuff

 

What can I do with a Nano VNA?




If you are up to it - here is Part II of my ¡°Nano VNA¡± talk to the MidAtlantic ARC in May 2021 at their monthly Zoom meeting. The first 30 minutes or so is their Business Meeting - so skip ahead.

Part I Nano VNA The Basics was the previous month, April 2021 - almost no math.
Looking at the Nano VNA like one more ¡°tool¡± in your tool box.

Part II (a look under the hood) I was not afraid to get deeper into the weeds - logs and return loss in dB and Smith Charts plotting resistance and reactance in POLAR form.

I did make TWO errors - see if you can spot them.

The Nano VNA device is rather remarkable. A fantastic tool for about $100 now.
Mine is almost three years old now - an original from Amazon with the SMA connectors.
Take the time to learn what a VNA can measure and compute.
Again I used Windows Nano VNA SAVER software (free) to produce these graphs.

Best wishes
De k3eui Barry
K3euiBarry - at - gmail.com
Re: BASIC PPT on the Nano VNA de k3eui Barry

 

On 12/7/22 7:31 AM, Donald S Brant Jr wrote:
On Wed, Dec 7, 2022 at 02:03 AM, Luc ON7DQ wrote:


that should of course be "at the Reflection socket" (or CH0)
I fail to understand why the designers of all of these VNAs labeled the ports CH0 and CH1, when every other VNA I have used over the past 45+ years has had Port 1 and Port 2.
This just adds to the confusion, especially when trying to explain S-parameters. S21/S12 makes more sense when the ports are 1 and 2, much less so with 0 and 1.
73, Don N2VGU
zero based indexing. The first person to build one happened to choose CH0 and CH1, and then it stuck.

Matlab and Fortran (and BASIC) follow the mathematician convention of 1 based.
C started zero based because of the array/pointer duality and the desire to keep the compiler simple.

Component numbering usually starts at 1, but often has a hundreds or thousands to indicate which board or assembly (that is, C302 is the second capacitor labeled on board #3)

Yeah - it's kind of like emacs vs vi; or case sensitive file and directory names. Someone picks something, and the rest follow, or not.
Re: BASIC PPT on the Nano VNA de k3eui Barry

 

On Wed, Dec 7, 2022 at 02:03 AM, Luc ON7DQ wrote:


that should of course be "at the Reflection socket" (or CH0)
I fail to understand why the designers of all of these VNAs labeled the ports CH0 and CH1, when every other VNA I have used over the past 45+ years has had Port 1 and Port 2.
This just adds to the confusion, especially when trying to explain S-parameters. S21/S12 makes more sense when the ports are 1 and 2, much less so with 0 and 1.
73, Don N2VGU
Re: BASIC PPT on the Nano VNA de k3eui Barry

 

... and for those that have trouble finding part two:


Barry's talk start around 20' into the meeting

73
Luc ON7DQ/KF0CR
Re: BASIC PPT on the Nano VNA de k3eui Barry

 

Hi Barry, great job with lots of practical examples !

Not sure if it is the error you meant, but at 37' in part 1, when talking about the OSL calibration, you said "from one socket to the other socket ...", that should of course be "at the Reflection socket" (or CH0)

73,
Luc ON7DQ/KF0CR
BASIC PPT on the Nano VNA de k3eui Barry

 




Here is a one hour PPT I did in March 2021 on the Nano VNA.
The club that recorded this presentation is in the Philly area.
The first portion is the ¡°business¡± meeting of the MidAtlantic ARC.
The rest of the video is a basic 3rd grade summary of what a Vector Network Analyzer can do. I try to keep the mathematics to an absolute minimum on the first hour talk.

Part II is another one hour, and delves into reflection coefficient (rho) and Return Loss (dB) and SWR and looks at phase more critically. Translate: more math.
The end of Part II deals with ¡­ yes ¡­. Calibration and Smith Charts.

Let me know if you spot the ERROR I made in Part I of the Nano VNA talk.

73
De k3eui
Barry
K3euiBarry-at-gmail.com
West Chester PA

December 06, 2022
Re: Best Firmware for NIB Deepelec NanoVNA-F?

 

Thanks, Roger.
I have joined the VNA-F IO Group and am currently "awaiting moderation." :)
Regards,
Kirk, NT0Z

My book, "Stealth Amateur Radio," is now available from www.stealthamateur.com and on the Amazon Kindle (soon)

On Tuesday, December 6, 2022 at 01:22:20 PM CST, Roger Need via groups.io <sailtamarack@...> wrote:

Kirk,

There are two manufacturers of the NanoVNA-F:? Deepelec (BH5HNU) and Sysjoint.? If you have a genuine Deepelec you can get the latest firmware and a Quick Start Guide at this link...
?

This group is great for general NanoVNA discussion.? There is a dedicated group for the NanoVNA-F and you will find a lot of good information there.? In particular the menu map.? /g/nanovna-f

If you are just starting out you will find the Absolute Beginners Guide to the NanoVNA very useful reading.? Ignore the section on upgrading firmware because the NanoVNA-F uses a different method.


Roger
Re: Best Firmware for NIB Deepelec NanoVNA-F?

 

Kirk,

There are two manufacturers of the NanoVNA-F: Deepelec (BH5HNU) and Sysjoint. If you have a genuine Deepelec you can get the latest firmware and a Quick Start Guide at this link...


This group is great for general NanoVNA discussion. There is a dedicated group for the NanoVNA-F and you will find a lot of good information there. In particular the menu map. /g/nanovna-f

If you are just starting out you will find the Absolute Beginners Guide to the NanoVNA very useful reading. Ignore the section on upgrading firmware because the NanoVNA-F uses a different method.


Roger
9781 - 9800 of 39697