Re: Audio frequency version of a NanoVNA
You don't often see Smith charts at audio frequencies because transmission-line techniques are less common, as is complex impedance matching in general. No reason why they couldn't be supported, of course.
The QuantAsylum QA403 is very nice, hardware-wise, for those who aren't content with sound cards. More expensive than a NanoVNA but still well under four digits.
-- john, KE5FX
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-----Original Message----- From: [email protected] < [email protected]> On Behalf Of Neil Preston W0NRP via groups.io Sent: Monday, November 11, 2024 8:11 AM To: [email protected]Subject: [nanovna-users] Audio frequency version of a NanoVNA Is there any practical way to make a VNA that provides the same measurements over the frequency range of ~10 Hz to maybe 1 MHz?
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Re: measuring gain of multi band vertival antenna (GAP Titan DX)
The major claim to fame of this type of antenna is not "gain" or "directivity", but coverage of all the amateur HF bands with one antenna with a single feedline. It is a compromise to accomplish that end. I seriously doubt it has any "gain" over a single-band properly installed and fed 1/4-wavelength vertical radiator. Dave - W?LEV On Wed, Nov 13, 2024 at 12:23?PM Jim Lux via groups.io <jimlux= [email protected]> wrote: Indeed but modeling multiband antennas with traps and internal components
with multiple coupling mechanisms can be full of interesting challenges
Sent via the Samsung Galaxy S24, an AT&T 5G smartphone
-------- Original message --------From: "Colin McDonald via groups.io"
<colinrmcdonald@...> Date: 11/12/24 11:21 PM (GMT+00:00)
To: [email protected] Subject: Re: [nanovna-users] measuring gain
of multi band vertival antenna (GAP Titan DX) This isn't something the
NanoVNA can measure. Any free antenna modelling software can tell you
though. Just download a flavor and enter all the antenna specifications it
asks for. It'll tell you what the angle of radiation is and where the
strongest gain is theoretically.Otherwise, you can use a field strength
meter to compare a dipole or a ground mounted quarter wave with radials to
the titan.However, a field strength meter won't always give you the most
accurate results if the antenna has an angle of radiation that passes over
where you are taking the measurements. Antennas present gain at specific
angles, what are called lobes. Depending on the type of antenna, quarter
wave, half wave, 5/8s wave, full wave etc the angle will be different.
It'll change depending on whether the antenna is a ground mounted vertical,
elevated, how many ground radials you have and of course near by
objects.Antenna modelling software calculates all of this information and
spits out data that can be useful to you.#1 is usually ground radials for a
ground mounted vertical antenna regardless of the radiating elements wave
length. The more quarter wave on the lowest operating frequency ground
radials you have, up to about 128, the better the antenna will perform.A
google search will also tell you what the estimated gain over a dipole or
gain over an isotropic radiator is for the dx titan antenna. Gain is
measured as a comparison in DB to either a dipole or an isotropic radiator.
Most manufacturers use DBI because it yields a larger number which makes
people believe the antenna has more gain. The antenna isn't an amplifier,
there is no magic going on that turns your 100 watts into a KW or
something. There is effected radiated power, but that is based entirely on
lobe radiation and a direct comparison of the nulls to the strongest lobes
of a particular antenna.None of which can be measured with a
NanoVNA.Theoretical math and formulas are used in the modelling software as
apposed to direct electrical measurements.73Colin VA6GGOn 2024-11-12 2:47
p.m., Michael E Wilson Sr via groups.io wrote:> Has anyone measured or
seen the gain factors for an antenna like the Tital DX. I have used one for
16 years, moved it to 4 different locations and it has never faild. But I
am curious about its gain on the divverent bands and would like to get a
measurement. Then may be I could see what is needed to improve it
operationj. Any information as to what equipment would be needed and the
procedures to follow would be appreciagted.>> Thanks.> 73> Mike Wilson>
KE5WCT> Daingerfield, Morris County, Texas (EM23ob)>>> >>
-- *Dave - W?LEV* -- Dave - W?LEV
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Re: Dislord v1.2.40 new MCU - frozen on startup
Try 1.2.42 Installed today, works fine (exc. wonky conn. to touch screen), great instructions here:
--
I_B_Nbridgema
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That's actually the main purpose of calibrating a VNA, to remove everything from the measurement except the DUT. 73, -de James/AC0CW On Wed, Nov 13, 2024, 13:13 Akai Moto via groups.io <akai.moto= [email protected]> wrote: Is it a viable method to do calibration of the VNA with a transmission
line attached, so that when the DUT is attached to end of that line the
measurements are true measurements of just the DUT?
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Re: Audio frequency version of a NanoVNA
Oops! Those who might want it, get it while you can - or else you will have to ask the Wayback Machine.
More and more creators of well-known software are retiring. Many of them go the extra mile when they do, and put the source code in the public domain, or waive the cost of formerly commercial programs, or at least warn their users to update while they can. Thanks to all of them!
A relatively recent case was Micro-CAP. I had been using the student/hobby version for years, and the end-of-support free release allowed me to get the full version.
When I retire, I intend to release the source code of the (few) programs I have written. So someone else can continue development, if anyone wants.
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Yes; in fact I had to do this to calibrate measurements made on a 1296 MHz bias tee using microstrip transmission lines. Zack W9SZ <> Virus-free.www.avg.com <> <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2> On Wed, Nov 13, 2024 at 12:13?PM Akai Moto via groups.io <akai.moto= [email protected]> wrote: Is it a viable method to do calibration of the VNA with a transmission
line attached, so that when the DUT is attached to end of that line the
measurements are true measurements of just the DUT?
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Yes. Instead of doing the OSL calibration at the unit, do the same at the end of the coaxial feedline. Outside of a bit of loss due to the coax, then your measurement plane will be at the end of the feedline. Dave - W?LEV On Wed, Nov 13, 2024 at 6:13?PM Akai Moto via groups.io <akai.moto= [email protected]> wrote: Is it a viable method to do calibration of the VNA with a transmission
line attached, so that when the DUT is attached to end of that line the
measurements are true measurements of just the DUT?
-- *Dave - W?LEV* -- Dave - W?LEV
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Is it a viable method to do calibration of the VNA with a transmission line attached, so that when the DUT is attached to end of that line the measurements are true measurements of just the DUT?
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Re: Dipole antenna with Low Z0 feed point Impedance
All of the suggestions that have been mentioned will probably work to lower the SWR - but will it make any real difference in your radiation? Probably not. In short runs of decent coax, any loss that is less than 1 dB means essentially no loss at all.
Again - try this first.
Just put a small inductor in parallel with the dipole at the feed point. That will raise the feedpoint closer to 50 ohms. You may have to then SHORTEN the dipole a bit (make it capacitive reactance) to keep the resonant frequency where you want it. That will cost you almost no $ to try.
This is the simple method often used to raise the feedpoint impedance of short mobile antennas used on HF.
You can wind your own inductor out of any kind of wire and try it.
The match will be better to 50 ohm coax.
But even if it works, it likely won¡¯t make MUCH difference in your situation.
Does the rig ¡°balk¡± at the load it now sees (with a 2:1) ?
de k3eui. barry
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Re: measuring gain of multi band vertival antenna (GAP Titan DX)
Indeed but modeling multiband antennas with traps and internal components with multiple coupling mechanisms can be full of interesting challenges? ?Sent via the Samsung Galaxy S24, an AT&T 5G smartphone
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-------- Original message --------From: "Colin McDonald via groups.io" <colinrmcdonald@...> Date: 11/12/24 11:21 PM (GMT+00:00) To: [email protected] Subject: Re: [nanovna-users] measuring gain of multi band vertival antenna (GAP Titan DX) This isn't something the NanoVNA can measure. Any free antenna modelling software can tell you though. Just download a flavor and enter all the antenna specifications it asks for. It'll tell you what the angle of radiation is and where the strongest gain is theoretically.Otherwise, you can use a field strength meter to compare a dipole or a ground mounted quarter wave with radials to the titan.However, a field strength meter won't always give you the most accurate results if the antenna has an angle of radiation that passes over where you are taking the measurements. Antennas present gain at specific angles, what are called lobes. Depending on the type of antenna, quarter wave, half wave, 5/8s wave, full wave etc the angle will be different. It'll change depending on whether the antenna is a ground mounted vertical, elevated, how many ground radials you have and of course near by objects.Antenna modelling software calculates all of this information and spits out data that can be useful to you.#1 is usually ground radials for a ground mounted vertical antenna regardless of the radiating elements wave length. The more quarter wave on the lowest operating frequency ground radials you have, up to about 128, the better the antenna will perform.A google search will also tell you what the estimated gain over a dipole or gain over an isotropic radiator is for the dx titan antenna. Gain is measured as a comparison in DB to either a dipole or an isotropic radiator. Most manufacturers use DBI because it yields a larger number which makes people believe the antenna has more gain. The antenna isn't an amplifier, there is no magic going on that turns your 100 watts into a KW or something. There is effected radiated power, but that is based entirely on lobe radiation and a direct comparison of the nulls to the strongest lobes of a particular antenna.None of which can be measured with a NanoVNA.Theoretical math and formulas are used in the modelling software as apposed to direct electrical measurements.73Colin VA6GGOn 2024-11-12 2:47 p.m., Michael E Wilson Sr via groups.io wrote:> Has anyone measured or seen the gain factors for an antenna like the Tital DX. I have used one for 16 years, moved it to 4 different locations and it has never faild. But I am curious about its gain on the divverent bands and would like to get a measurement. Then may be I could see what is needed to improve it operationj. Any information as to what equipment would be needed and the procedures to follow would be appreciagted.>> Thanks.> 73> Mike Wilson> KE5WCT> Daingerfield, Morris County, Texas (EM23ob)>>> >>
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Re: Measure transformers, inductors and trap filters
Mike M really interesting fixture it looks really good. I'll probably try to make it with our european version of the electric connector (wago, it looks the same).
William I took a look at the book you recommended and bought it, I have finished the part about the smith chart and it's indeed really good.
I definitely prefer text (or book) explanation than video so it's really cool, thanks for the advice !
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Re: measuring gain of multi band vertival antenna (GAP Titan DX)
A co-linear vertical dipole design. Using coax as the elements to linearly load the element.
Fed like a dipole in the middle instead of an end fed like most vertical antennas.
Sure you can put that into modelling software. Though perhaps not the free ones.
Also, an educated guess suggests gain would be the same as a dipole, or a DB or two more in the strong lobes at particular direction and angle.
The manual for these is online.
I am unaware of any equipment other than field strength equipment used to compare a known antenna like a dipole, that can provide a gain measurement.
How do they determine that a particular antenna has gain? Well, it's theoretical for the most part, but antenna makers also measure the field strength of the antenna to determine how much RF energy is being sent out and in what direction and at what angle.
Or they should. I suspect most just provide standard estimates based on the physical design of the antenna and don't really test anything beyond the stuff you can check on a NanoVNA.
73
Colin, VA6GG
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On 2024-11-12 8:26 p.m., Michael E Wilson Sr via groups.io wrote: Modeling wont work. This antenna uses multi coax sections folded and placed inside the tube, with the feed point at the mid point, and section dropping below the tube with the coax connector. So far I have found no one that has the spects for all of the bands. It covers 80 thru 10 meters (less 160 and 60 meters). It is a great antenna, I would just like to know more about it.
Hope someone out there has de-structed one and figured how it is put togethere and has some written data stored away somewhere.
73
Mike, KE5WCT
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Re: measuring gain of multi band vertival antenna (GAP Titan DX)
Why not contact the manufacturer and ask?
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Re: measuring gain of multi band vertival antenna (GAP Titan DX)
Modeling wont work. This antenna uses multi coax sections folded and placed inside the tube, with the feed point at the mid point, and section dropping below the tube with the coax connector. So far I have found no one that has the spects for all of the bands. It covers 80 thru 10 meters (less 160 and 60 meters). It is a great antenna, I would just like to know more about it.
Hope someone out there has de-structed one and figured how it is put togethere and has some written data stored away somewhere.
73
Mike, KE5WCT
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Re: Dipole antenna with Low Z0 feed point Impedance
Yes, two parallel connected 1/4 electrical wavelengths of 75-ohm cable will map 25-ohms to 50-ohms. That's the easiest solution. I don't know of any single reference for using coaxial matching stube. Just remember the following as applies to electrical 1/4 wavelength stubs: Z(of series matching stub) = SQRT [Zs x Zl] where Zs = the source impedance Zl = load impedance Further, any impedance transmission which is a 1/2 electrical wavelength will map the source impedance with no modification other than a bit of loss. As far as learning about matching stubs, the best I could recommend is to download, install, and play with SimSmith. Here are a few online resources: https://www.arcticpeak.com/antennapages/quaterwavestub.htm\ (Ellingson)/03%3A_Transmission_Lines/3.19%3A_Quarter-Wavelength_Transmission_Line Dave - W?LEV On Wed, Nov 13, 2024 at 12:47?AM Bill WA2WIO via groups.io <sla= [email protected]> wrote: Dave, Frank;
Wow! Thank you for the detailed suggestions.
Question: How would tuned stubs accommodate multiple bands? 40m (1/2 wave
nom 66ft)/20m (nom full wave), maybe even 15m (nom 3/4 wave)?
Also, what if the dipole is not perfectly balanced (probably far from it?)
and Z0 is not purely resistive?
Where can I read up on the theory behind using tuned impedance matching
stubs?
I think I may need to move a cot into the attic. It seems I will be
spending some time up there! ?
Best,
Bill WA2WIO
-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf
Of DP via groups.io
Sent: Monday, November 11, 2024 2:25 PM
To: [email protected]
Subject: Re: [nanovna-users] Dipole antenna with Low Z0 feed point
Impedance
Hi Frank,
I'm a huge fan of yours, and very grateful for your countless
contributions that continue to elevate the hobby. Many many thanks! Yes, I
counted your suggestion of two 1/4-wave sections of 75-ohm coax in parallel
as one of the best. Regarding effective bandwidth, that method will also be
dominated by that of the antenna.
Best 73s,
Dave NU8A
On Mon, Nov 11, 2024 at 01:26 PM, Frank Donovan wrote:
Dave forgot to model what is likely to be the broadest bandwidth solution
using coaxial cable: Two 90 degree lengths of 75 ohm coax in parallel
73
Frank
W3LPL
-- *Dave - W?LEV* -- Dave - W?LEV
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Re: Dipole antenna with Low Z0 feed point Impedance
Dave, Frank;
Wow! Thank you for the detailed suggestions.
Question: How would tuned stubs accommodate multiple bands? 40m (1/2 wave nom 66ft)/20m (nom full wave), maybe even 15m (nom 3/4 wave)?
Also, what if the dipole is not perfectly balanced (probably far from it?) and Z0 is not purely resistive?
Where can I read up on the theory behind using tuned impedance matching stubs?
I think I may need to move a cot into the attic. It seems I will be spending some time up there! ?
Best,
Bill WA2WIO
toggle quoted message
Show quoted text
-----Original Message----- From: [email protected] [mailto: [email protected]] On Behalf Of DP via groups.io Sent: Monday, November 11, 2024 2:25 PM To: [email protected]Subject: Re: [nanovna-users] Dipole antenna with Low Z0 feed point Impedance Hi Frank, I'm a huge fan of yours, and very grateful for your countless contributions that continue to elevate the hobby. Many many thanks! Yes, I counted your suggestion of two 1/4-wave sections of 75-ohm coax in parallel as one of the best. Regarding effective bandwidth, that method will also be dominated by that of the antenna. Best 73s, Dave NU8A On Mon, Nov 11, 2024 at 01:26 PM, Frank Donovan wrote:
Dave forgot to model what is likely to be the broadest bandwidth solution
using coaxial cable: Two 90 degree lengths of 75 ohm coax in parallel
73
Frank
W3LPL
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Re: measuring gain of multi band vertival antenna (GAP Titan DX)
This isn't something the NanoVNA can measure. Any free antenna modelling software can tell you though. Just download a flavor and enter all the antenna specifications it asks for. It'll tell you what the angle of radiation is and where the strongest gain is theoretically.
Otherwise, you can use a field strength meter to compare a dipole or a ground mounted quarter wave with radials to the titan.
However, a field strength meter won't always give you the most accurate results if the antenna has an angle of radiation that passes over where you are taking the measurements. Antennas present gain at specific angles, what are called lobes. Depending on the type of antenna, quarter wave, half wave, 5/8s wave, full wave etc the angle will be different. It'll change depending on whether the antenna is a ground mounted vertical, elevated, how many ground radials you have and of course near by objects.
Antenna modelling software calculates all of this information and spits out data that can be useful to you.
#1 is usually ground radials for a ground mounted vertical antenna regardless of the radiating elements wave length. The more quarter wave on the lowest operating frequency ground radials you have, up to about 128, the better the antenna will perform.
A google search will also tell you what the estimated gain over a dipole or gain over an isotropic radiator is for the dx titan antenna. Gain is measured as a comparison in DB to either a dipole or an isotropic radiator. Most manufacturers use DBI because it yields a larger number which makes people believe the antenna has more gain. The antenna isn't an amplifier, there is no magic going on that turns your 100 watts into a KW or something. There is effected radiated power, but that is based entirely on lobe radiation and a direct comparison of the nulls to the strongest lobes of a particular antenna.
None of which can be measured with a NanoVNA.
Theoretical math and formulas are used in the modelling software as apposed to direct electrical measurements.
73
Colin VA6GG
toggle quoted message
Show quoted text
On 2024-11-12 2:47 p.m., Michael E Wilson Sr via groups.io wrote: Has anyone measured or seen the gain factors for an antenna like the Tital DX. I have used one for 16 years, moved it to 4 different locations and it has never faild. But I am curious about its gain on the divverent bands and would like to get a measurement. Then may be I could see what is needed to improve it operationj. Any information as to what equipment would be needed and the procedures to follow would be appreciagted.
Thanks.
73
Mike Wilson
KE5WCT
Daingerfield, Morris County, Texas (EM23ob)
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measuring gain of multi band vertival antenna (GAP Titan DX)
Has anyone measured or seen the gain factors for an antenna like the Tital DX. I have used one for 16 years, moved it to 4 different locations and it has never faild. But I am curious about its gain on the divverent bands and would like to get a measurement. Then may be I could see what is needed to improve it operationj. Any information as to what equipment would be needed and the procedures to follow would be appreciagted.
Thanks.
73
Mike Wilson
KE5WCT
Daingerfield, Morris County, Texas (EM23ob)
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Did H4 need a Screw to fixe the SMA connector to the case
Hi All
Did H4 version need an external screws to fixe the two SMA connectors to the plastic case , indeed electronic board should not have an excessive mecanical constrainte during SMA feeting to keep calibration stability for longtime with a good -70db range ??
73's Nizar
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Re: Dipole antenna with Low Z0 feed point Impedance
1:2 would mean SWR 0.5 A SWR less then one is impossible. 73 Peter, DJ7WW -----Original-Nachricht----- Betreff: Re: [nanovna-users] Dipole antenna with Low Z0 feed point Impedance Datum: 2024-11-12T16:48:32+0100 Von: "Siegfried Jackstien via groups.io" <siegfried.jackstien@...> An: " [email protected]" < [email protected]> some rigs are not that happy with 1:2 SWR dg9bfc sigi Am 12.11.2024 16:10 schrieb "Warren Allgyer via groups.io" <allgyer@...>:
You have a resonant antenna with an SWR of 2:1 which is completely
inconsequential at 40 and 20 meters. There is no functional reason to do
anything to correct this; you will see no improvement in transmit or
receive from doing so. I understand the intellectual and experimenter's
challenge in achieving an SWR closer to 1:1 but your rig will work fine at
that SWR and you achieve nothing other than satisfaction of doing it.
Personally, I would spend my time and effort elsewhere where it might make
a difference.
Warren Allgyer - WA8TOD
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Nbridgema
Barry K3EUI
Michael E Wilson Sr