开云体育

*
*

*
*

*???? Multi-Band? HF?? Vertical*

*
*

*In an effort to get a?? VERTICAL ANTENNA ? up for the 20/17/15/10 meter bands, I tried setting up a 14 ft vertical antenna*

*made from old aluminum tubing, mounted 3 ft above ground, adjacent to a 20 ft vertical aluminum rain gutter - mounted just inches from it for close coupling.*

*Set up three radials - two were 13 feet and one was 33 ft. **No matching of any kind.*

*
*

*Results were surprising as the rain gutter makes this vertical into a reasonable multi-band vertical for 20/15/10 meters.
*

*Cost was almost nothing.*

*Fed with 50 ft of RG8X and a coax choke at the input to the antenna terminal.*


*I'll have to try it out this weekend on 20/15/10m digital and see if it radiates a low-angle DX signal.*

*de k3eui? barry*

Your coax is only going to have a "resonant frequency" if it is terminated
in a very high SWR or a load with a very high or low impedance, such as an
open or short. If the load is somewhere close to 50 ohms, you aren't going
to see any resonant frequency that is worth any concern.

Zack W9SZ

<>
Virus-free.www.avg.com
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<#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>

On Fri, Mar 21, 2025 at 6:56?AM Team-SIM SIM-Mode via groups.io <sim31_team=
[email protected]> wrote:

Hi

DiSlord Coax Zc measurement function, already installed on H4 1.2.40
firmware, seems need to measure C0 capacitance @ 100Khz and the f0 first
coax resonance frequency (Hz) and then we calculate Zc = 1/(4 x f0 x c0)
Ohm , I appreciate it a lot.

Can we do some accuracy correction ? indeed diélectric permittivity of
polyethylene diélectric can vary with fréquency , it can decrease slowly up
to -4.5% from 100Khz to 14.1Mhz for example , so we can correct C0 value by
-4.5% and then ZC should be increased by +4.5% to be more accurate @ 14
Mhz Zc measurement .

if our coax has 22.28 metre long with Vp around 83% , the first resonnance
frequency will be around 2.71 Mhz wich still far from 14Mhz and may be
some % error may be done , I prefer to measure the resonnance or
antiresonance the nearest to the 14Mhz and devide by number for correction
to have the more accurate Zc value based on measurement done as near as
possible to the desired frequency ..

What you think about all this view , or DiSlord has already taken in
consideration all this possible corrections .

73's Nizar .

Since you asked what we think - I think this:

For amateur radio use, there is no reason that I know of to have high accuracy in the measurement of cable impedance.
It may be fun for an intellectual exercise, but practically, all we need to know is if the coax is 50-ohm, 75-ohm, 92-ohm, etc., with enough accuracy that we can see that it is a good cable. And DiSlord's current algorithm gives at least this level of accuracy.
We combine that measurement of impedance with a loss measurement and perhaps an electrical and physical length measurement to evaluate a cable's suitability for our purpose.

Even the best coax cables are not 'exact' in their impedance, and in fact, due to manufacturing tolerances, may vary a couple of percentage points of impedance along the length of the cable. A 50-ohm cable that measures 49.1 ohms of impedance is just fine. These variations and minor differences from an 'exact' 50-ohms or 75-ohms make almost no difference in actual use of the cable for any practical purpose. (The VSWR resulting from the difference between 49.1 and 50 ohms is only 1.018:1.)

The 'loss' calculation of the cable is of much more practical use than impedance, since it will determine power delivered to the load, extra loss due to SWR, etc. But even that loss measurement only needs to be 'reasonably' accurate, maybe to 10ths of a dB, for almost any practical amateur radio application. And when building matching stubs with coax, we have to measure the electrical length anyway, which measurement includes any variation due to imperfect impedance. So again, I don't put any value on highly-accurate cable impedance measurements.

Stan KC7XE

for my saa2n i have cal standards with plugs (male connector) .. but i wanted also female (so i can calibrate at cable end with a plug without double female needed)

so i took 3 N sockets .. one with a short .. one with an open .. and third got 2x 100 Ohms SMD resistors in parallel (centre pin shorted on all three to exact same length)

works good to over 3 ghz :-)

dg9bfc sigi

adding a "keyring" to secure them against getting lost

Am 21.03.2025 um 18:21 schrieb W0LEV via groups.io:

QUOTE: ....a DIY fixture can be made using a female SMA connector with its
centre conductor sawn to the same level as the dielectric. .....
***

You can buy such a connector with no need to clip off the tip. They are
known as launchers and instead of the cylindrical tip, contain a short
ribbon connector meant to be directly soldered to a microstrip trace.

Dave - W?LEV

On Fri, Mar 21, 2025 at 7:30?AM biastee via groups.io <biastee=
[email protected]> wrote:

On Mon, Mar 17, 2025 at 03:22 PM, W0LEV wrote:

best "amateur" fixture is to solder cal. standards and test items to the
butt end of an SMA female connector - WITH ABSOLUTELY NO LEADS.

Indeed, the HP16092A is the butt end of an APC-7 connector, with just 3mm
of the centre conductor protruding beyond the insulator. It has an
advertised max freq of 500 MHz.
I agree with Dave that a DIY fixture can be made using a female SMA
connector with its centre conductor sawn to the same level as the
dielectric. Then, a plastic bulldog clip (similar to one in the photo of
the S21 fixture) can be used to clamp the chip component down.
I have measured a 89 nH inductor (6.5 turn, ID2.9mm) using the 1st type of
fixture (fixt s11.jpg). The fixture is calibrated using a 1206 size 50ohm
chip, and a brass shorting bar. Using the nanoVna V2+, the S11 from 10 to
1000 MHz (s11.jpg). The self-resonance is above 1000 MHz. The trace stays
inside the chart. The Q can be calculated from the impedance = R+jX at
different freqs.
According to HP/KS, the VNA has poor accuracy when the S11 trace is near
the perimeter. Hence, I also measured the same inductor using the S21
method in a microstrip fixture (fixt s21.jpg). A plastic bulldog clip is
used to clamp the inductor to the PCB. The fixture is calibrated bridging
the microstrip gap with a brass bar (thru). The measured and modeled S21
points a parasitic cap of 0.16 pF (s21_gra.jpg)

--

*Dave - W?LEV*


--
Dave - W?LEV

On Tue, Mar 18, 2025 at 04:17 PM, ae1th@... wrote:

look in files section, menuand notes by bruce dated 2024, good menu map and
notes

Wanted to add another "thank you" for posting that information. I've had nanoVNAs since they first emerged (2019?), and a ham friend recently gave me one dated from that era. Had never been updated, i.e. I had to dig through my boxes to locate a "grabber" to jumper the BOOT/VDD pins and enter the DFU mode. After I updated it to the latest DisLord firmware I began wondering if someone had compiled a current menu structure, and BINGO, I found it here.

To this day it still staggers me how inexpensive, powerful and useful these tiny nanoVNAs are. When I received my very first one I was so blown away after using it to test some filters that I rushed to order a second one, convinced that it was "too good to be true". Surely there must me some mistake for this capability to be had so cheaply, I thought(!).

Hi

DiSlord Coax Zc measurement function, already installed on H4 1.2.40 firmware, seems need to measure C0 capacitance @ 100Khz and the f0 first coax resonance frequency (Hz) and then we calculate Zc = 1/(4 x f0 x c0) Ohm , I appreciate it a lot.

Can we do some accuracy correction ? indeed diélectric permittivity of polyethylene diélectric can vary with fréquency , it can decrease slowly up to -4.5% from 100Khz to 14.1Mhz for example , so we can correct C0 value by -4.5% and then ZC should be increased by +4.5% to be more accurate @ 14 Mhz Zc measurement .

if our coax has 22.28 metre long with Vp around 83% , the first resonnance frequency will be around 2.71 Mhz wich still far from 14Mhz and may be some % error may be done , I prefer to measure the resonnance or antiresonance the nearest to the 14Mhz and devide by number for correction to have the more accurate Zc value based on measurement done as near as possible to the desired frequency ..

What you think about all this view , or DiSlord has already taken in consideration all this possible corrections .

73's Nizar .

On Fri, Mar 21, 2025 at 12:29 AM, <biastee@...> wrote:

I also measured the same inductor using the S21 method

Please post the .s2p file. I'd like to calculate results using the Y21 method that suppresses stray, shunt capacitance in the test fixture.

Brian

On Mon, Mar 17, 2025 at 03:22 PM, W0LEV wrote:

best "amateur" fixture is to solder cal. standards and test items to the
butt end of an SMA female connector - WITH ABSOLUTELY NO LEADS.

Indeed, the HP16092A is the butt end of an APC-7 connector, with just 3mm of the centre conductor protruding beyond the insulator. It has an advertised max freq of 500 MHz.
I agree with Dave that a DIY fixture can be made using a female SMA connector with its centre conductor sawn to the same level as the dielectric. Then, a plastic bulldog clip (similar to one in the photo of the S21 fixture) can be used to clamp the chip component down.
I have measured a 89 nH inductor (6.5 turn, ID2.9mm) using the 1st type of fixture (fixt s11.jpg). The fixture is calibrated using a 1206 size 50ohm chip, and a brass shorting bar. Using the nanoVna V2+, the S11 from 10 to 1000 MHz (s11.jpg). The self-resonance is above 1000 MHz. The trace stays inside the chart. The Q can be calculated from the impedance = R+jX at different freqs.
According to HP/KS, the VNA has poor accuracy when the S11 trace is near the perimeter. Hence, I also measured the same inductor using the S21 method in a microstrip fixture (fixt s21.jpg). A plastic bulldog clip is used to clamp the inductor to the PCB. The fixture is calibrated bridging the microstrip gap with a brass bar (thru). The measured and modeled S21 points a parasitic cap of 0.16 pF (s21_gra.jpg)

Hi Dave,

1- I've upload the Kicad project as a zip file.
2- I also upload a PDF showing this part of the schematic and layout with different zoom levels in case you can't download or open the Kicad project.
3- The manufacturer (TE Connectivity) suggest a 3 element matching network (as pictured in the datasheet) to compensate for the final mounting conditions (plastic case). I've implemented what they suggest, leaving the pads unpopulated. I tried soldering only a series inductor. I used SimSmith software to simulate the required value.
4- For all the tests you've requested me, I've populated the series element with a 0 ohm resistor.
5- I'm in the process of modifying the schematic and layout. As a real amateur, I mixed up the transceiver pinout with a different model. When I came to fully assemble one of the boards, I realized it would have never worked.
The schematic I attached is the modified version I'm working on. I haven't moved the antenna or modified the ground plane dimension nor its shape. only the position of the LoRa module and the transmission line shape.

6- WOW ! Huge findings tonight ! I moved the ferrite decoupled coax AFTER the matching circuit, right at the antenna. Look at the pdf I have attached. The results are in the last 4 pages.
Essentially, Even with the PCB mounted in its case, the VSWR stays relatively acceptable under all across the full ISM bandwidth from 902 to 928. The response is more flat and "clean".
This suggests me there is something wrong with the transmission line in the section where there is a ground plane.

Thank you so much once again for all your dedication helping me

Nicolas

Howard,

I used the SMA to SMA jumper cables which came with the Nano VNA and
calibrated using the open, short and load connectors (
). Then I used an SMA to SO239 adapter on the
jumper cables as my antennas have PL259 termination and it worked well.
Somehow it did not work well when I used PL259 open, short and load for
calibration.

If your antennas have SMA termination, then there is no need to use the
adapter. I did not use any software other than the built-in software in the
Nano VNA.

73
Jon, VU2JO

On Thu, Mar 20, 2025 at 11:07?PM Howard via groups.io <n9ktw=
[email protected]> wrote:

Hey guys

just got a nano VNA. it is a "seesii, nano VNA-H.

I need some help in setting it up to see the SWR on some antennas. I have
gone through the various manuals and the one that came with it, and I am
very confused.

Basically what I am looking to do is (to me ) very simple. Input a start
frequency, lets say 144 MHz. A stop frequency, say 152 MHz. The see the
lowest SWR point as an inverted bell curve.

Anyone have any ideas how to do this? Also, I cannot seem to find the
correct software for the device. I know my cable is good (as I can get data
off my cell phone with it) but i cant the nano VNA to be recognized.

Please help.


Howard

Well, simply put:

First, do an OSL calibration for the range you want to use, and store it in
one of the memories.

Then select Display > S11 > SWR. It should then display the SWR of whatever
is connected to the S11 (upper) connector.

Very simple.

Zack W9SZ

<>
Virus-free.www.avg.com
<>
<#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>

On Thu, Mar 20, 2025 at 12:37?PM Howard via groups.io <n9ktw=
[email protected]> wrote:

Hey guys

just got a nano VNA. it is a "seesii, nano VNA-H.

I need some help in setting it up to see the SWR on some antennas. I have
gone through the various manuals and the one that came with it, and I am
very confused.

Basically what I am looking to do is (to me ) very simple. Input a start
frequency, lets say 144 MHz. A stop frequency, say 152 MHz. The see the
lowest SWR point as an inverted bell curve.

Anyone have any ideas how to do this? Also, I cannot seem to find the
correct software for the device. I know my cable is good (as I can get data
off my cell phone with it) but i cant the nano VNA to be recognized.

Please help.


Howard

"NanoVNAs Explained" by Mike Richards G4WNC is the goto book you need,
available from a number of Internet shops.

73 DE G4SDW Gareth

Welcome to the group!

The archives of this group contain much good information including videos
and a guide for the VNAs for DUMMIES. Those resources should get you
going.

Dave - W?LEV

On Thu, Mar 20, 2025 at 5:37?PM Howard via groups.io <n9ktw=
[email protected]> wrote:

Hey guys

just got a nano VNA. it is a "seesii, nano VNA-H.

I need some help in setting it up to see the SWR on some antennas. I have
gone through the various manuals and the one that came with it, and I am
very confused.

Basically what I am looking to do is (to me ) very simple. Input a start
frequency, lets say 144 MHz. A stop frequency, say 152 MHz. The see the
lowest SWR point as an inverted bell curve.

Anyone have any ideas how to do this? Also, I cannot seem to find the
correct software for the device. I know my cable is good (as I can get data
off my cell phone with it) but i cant the nano VNA to be recognized.

Please help.


Howard

--

*Dave - W?LEV*


--
Dave - W?LEV

Hey guys

just got a nano VNA. it is a "seesii, nano VNA-H.

I need some help in setting it up to see the SWR on some antennas. I have gone through the various manuals and the one that came with it, and I am very confused.

Basically what I am looking to do is (to me ) very simple. Input a start frequency, lets say 144 MHz. A stop frequency, say 152 MHz. The see the lowest SWR point as an inverted bell curve.

Anyone have any ideas how to do this? Also, I cannot seem to find the correct software for the device. I know my cable is good (as I can get data off my cell phone with it) but i cant the nano VNA to be recognized.

Please help.


Howard

1- Would you recommend to clean all 3 elements of the matching network, as
I don't know which component will go where ?

Can you send me a schematic of the matching network? Possibly I can figure
it out. Is the matching network from the supplier or derived from you VNA
measurements?

I'm annal, but could you give me a clean S11 measurement from 902 through
928 MHz (the entire ISM band) of the unit in its case. Clearly the
dielectric of the plastic case is strongly affecting the behavior of the
antenna.

Looking at your previous postings, I can only conclude the antenna designer
developed that out of the plastic case. I seriously doubt he/she evey
evaluated the result that is published in the plastic case. I base that on
the relatively good S11 outside the case only requiring a single 10 nH
series inductor against the relatively poor S11 when inside the case.

Yet another request: Measure and send to me an S11 measurement of ONLY the
antenna. Attach the ferrite decoupled coax at the point on the PCB where
the transmitter energy is connected directly to the antenna with no
intervening components. I wat to determine how the antenna behaves both
inside and outside the plastic case.

2- If you look at the trace between the components, you'll see I made the
trace the same width as the pad. Is this a good idea ? The pad's center to
center is 4mm. The trace 0.9 wide, with a surrounding ground plane and via
fencing I treat it as a coplanar wave guide and the rest of the trace and
clearance are in accordance with that. The idea behind making the trace
between the component is to avoid width bumps.

Since these low power "transmitters" are pretty insensitive to SWR (or
reflection coefficient), I believe you did the right thing by keeping the
trace width the same as the pad for the series inductor. Of course, this
avoids an impedance bump in the path to the antenna.

3- Is my via fencing overkill putting them shoulder to shoulder ? Would a
1/10th of 1/4 wave spacing be enough for a coplanar wave guide ?

We typically use 1/10 spacing between the vias. However, that is not the
free space spacing but the spacing within the dielectric, Vp. Vp in a
dielectric goes as the reciprocal of the SQRT of the relative dielectric
constant of the dielectric medium. Since you are using FR-4, in round
numbers, the dielectric constant would be {SQRT [avg(3.8 and 4.8)]}^-1 =
{SQRT [4.3]}^-1 = 0.482. This multiplied by the free space spacing will
give you the "in-dielectric" spacing.

Yes, the via "fence" is always recommended to confine fringing fields from
propagating throughout the dielectric.

4- Could you suggest me a type of inductor in particular that would
appropriate in the 0603 package for what I'm doing ?

Typically, these days as a result of the cell phone and WiFi industries
operating up to and including 5 GHz, most of these parts are OK for the 900
MHz ISM band and through the 5 GHz ISM band. However, I still recommend
cleaning any copper from under the SM inductors and/or capacitors.

BTW, Yesterday I took a reading with the board flat outside its case. I had
installed 2 ferrite in a row along the cable. I had a VSWR of 1.19:1 all
across the bandwidth from 900 to 930MHz which is better than the spec
sheet. If only I could get below 2 while in its case...

This is why I'm requesting measurements of both the antenna only inside and
outside the case with your ferrite decoupled coax leading to the VNA.
Recently, I've had a couple of (paid) jobs where the plastic case
significantly altered the behavior of the intended antenna. You're not
alone, be rest assured.

We are finally touching on the design "gotcha's" regarding PCB design at ?W
frequencies. Possibly we should take this off the nanovna group. But,
it's still good information for those unfamiliar with these techniques.
Please let us (I'm one of the moderators of this group) if this thread bugs
anyone. It's good information for everyone concerned and certainly touches
on applications of the NANOVNA and any VNA.

Dave - W?LEV

On Thu, Mar 20, 2025 at 12:53?AM Nico via groups.io <nicolassimard=
[email protected]> wrote:

Dave,

Thanks for the hint.
1- Would you recommend to clean all 3 elements of the matching network, as
I don't know which component will go where ?
2- If you look at the trace between the components, you'll see I made the
trace the same width as the pad. Is this a good idea ? The pad's center to
center is 4mm. The trace 0.9 wide, with a surrounding ground plane and via
fencing I treat it as a coplanar wave guide and the rest of the trace and
clearance are in accordance with that. The idea behind making the trace
between the component is to avoid width bumps.
3- Is my via fencing overkill putting them shoulder to shoulder ? Would a
1/10th of 1/4 wave spacing be enough for a coplanar wave guide ?
4- Could you suggest me a type of inductor in particular that would
appropriate in the 0603 package for what I'm doing ?

BTW, Yesterday I took a reading with the board flat outside its case. I
had installed 2 ferrite in a row along the cable. I had a VSWR of 1.19:1
all across the bandwidth from 900 to 930MHz which is better than the spec
sheet. If only I could get below 2 while in its case...

Thanks,

--

*Dave - W?LEV*


--
Dave - W?LEV

Dave,

Thanks for the hint.
1- Would you recommend to clean all 3 elements of the matching network, as I don't know which component will go where ?
2- If you look at the trace between the components, you'll see I made the trace the same width as the pad. Is this a good idea ? The pad's center to center is 4mm. The trace 0.9 wide, with a surrounding ground plane and via fencing I treat it as a coplanar wave guide and the rest of the trace and clearance are in accordance with that. The idea behind making the trace between the component is to avoid width bumps.
3- Is my via fencing overkill putting them shoulder to shoulder ? Would a 1/10th of 1/4 wave spacing be enough for a coplanar wave guide ?
4- Could you suggest me a type of inductor in particular that would appropriate in the 0603 package for what I'm doing ?

BTW, Yesterday I took a reading with the board flat outside its case. I had installed 2 ferrite in a row along the cable. I had a VSWR of 1.19:1 all across the bandwidth from 900 to 930MHz which is better than the spec sheet. If only I could get below 2 while in its case...

Thanks,

Yes. The TINYSA is highly useful for frequency domain measurements.

As well, the NANOVNA is equally useful for impedance domain measurements.

As well, an o'scope is equally useful for time and amplitude domain
measurements.

Any ham should have all of the above!

In these modern times, none of the above will break the check book or
credit card.

Dave - W?LEV



On Wed, Mar 19, 2025 at 6:22?PM Donald Kirk via groups.io <wd8dsb=
[email protected]> wrote:

The calibrated signal generator output on the TinySA Ultra is a great tool
to calibrate or check your S meter and also very useful for determining
and/or checking your receivers sensitivity. It also provides modulated AM
and FM modulated outputs(AM amplitude as well as modulation frequency
adjustable, FM deviation adjustable). The TinySA Ultra is a great tool for
checking a transmitters harmonic content assuming you have appropriate
attenuators. The TinySA Ultra is useful for viewing and sniffing out
sources of RFI. The tinySA Ultra can view a much much larger spectrum than
a SDR receiver. The TinySA Ultra can measure a transmitters output level
assuming you use appropriate attenuators, the TinySA Ultra can be used to
make accurate field strength measurements if you know the antenna factor.
I’m sure there are many other useful options/features but the ones I listed
are common features that I use all the time. The TinySA can do most of
what the TinySA Ultra can do but it’s more limited.

--

*Dave - W?LEV*


--
Dave - W?LEV

The calibrated signal generator output on the TinySA Ultra is a great tool to calibrate or check your S meter and also very useful for determining and/or checking your receivers sensitivity. It also provides modulated AM and FM modulated outputs(AM amplitude as well as modulation frequency adjustable, FM deviation adjustable). The TinySA Ultra is a great tool for checking a transmitters harmonic content assuming you have appropriate attenuators. The TinySA Ultra is useful for viewing and sniffing out sources of RFI. The tinySA Ultra can view a much much larger spectrum than a SDR receiver. The TinySA Ultra can measure a transmitters output level assuming you use appropriate attenuators, the TinySA Ultra can be used to make accurate field strength measurements if you know the antenna factor. I’m sure there are many other useful options/features but the ones I listed are common features that I use all the time. The TinySA can do most of what the TinySA Ultra can do but it’s more limited.

On Wed, Mar 19, 2025 at 09:17 AM, James Henscheid wrote:

Haven’t bought one yet but I’d like to make sure I get a version capable
of the TDR addition. I’ll have to figure out how to add it if necessary
after receiving it.
Thanks.

Hi James , the nanovna H H4 and LiteVNA64 , whith the recent FW
has the TDR function but named TRANSFORM .
You can reach the relative menu , tapping the DISPLAY >> TRANSFORM >> TRANSFORM ON.
In the pictures , the 270mm cable connected to CH0 .
Regards Maurizio IZ1MDJ