Re: How To Do A SWR Sweep on 2 Meter HT Antenna ?
I agree with Jim Lux. Holding the VNA in your hand is both simple and probably the most representative of the performance with an HT. In the olden days, the German VDE 0871 testing standard used a salt water column with a plate on top for testing hand-held devices. Jim's suggestion lets you simulate you!
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Re: Fixture de-embedding for component measurement
On 11/4/22 8:04 AM, Brent DeWitt wrote: The parts I'm currently playing with are all Laird ( formerly Steward) 28 alloy, with the Z peaking in the 100-200 MHz region. The data I'm referencing is from their data sheets.
I'll read through Jim's paper. Thanks!
What test fixture are you using? 1 or a few turns through the core? Note that these things have about 20% tolerance with respect to the datasheet values, too.
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Re: Fixture de-embedding for component measurement
The parts I'm currently playing with are all Laird ( formerly Steward) 28 alloy, with the Z peaking in the 100-200 MHz region. The data I'm referencing is from their data sheets.
I'll read through Jim's paper. Thanks!
Brent AB1LF
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Re: Fixture de-embedding for component measurement
What ferrites and where's the reference for them.
Jim K9YC has done some fairly extensive choke testing.
Mike W9MDB
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On Thursday, November 3, 2022 at 07:43:56 PM CDT, Brent DeWitt <bdewitt@...> wrote:
I having fits trying to measure lossy "soft" ferrites against the manufacturers curves.? Over the range 1 to 300 MHz, I'm not even getting close, looking at either S11 into a short or S21.? I've tried a few home-brew fixtures, and they all yield a Z which is much lower than the published data, so I'm thinking it is my fixturing and calibration that are doing me in.
For those that have been successful:
- Do you perform you OSL cal at the input port to the fixture, or the far side?
- Is your preferred method S11 into a short, S11 into 50 ohms, or S21?
Just to set the level of conversation; I'm quite comfortable driving around a Smith Chart and have been involved in RF for a very long time, so feel free to pick me apart!
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Fixture de-embedding for component measurement
I having fits trying to measure lossy "soft" ferrites against the manufacturers curves. Over the range 1 to 300 MHz, I'm not even getting close, looking at either S11 into a short or S21. I've tried a few home-brew fixtures, and they all yield a Z which is much lower than the published data, so I'm thinking it is my fixturing and calibration that are doing me in.
For those that have been successful:
- Do you perform you OSL cal at the input port to the fixture, or the far side?
- Is your preferred method S11 into a short, S11 into 50 ohms, or S21?
Just to set the level of conversation; I'm quite comfortable driving around a Smith Chart and have been involved in RF for a very long time, so feel free to pick me apart!
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On 11/2/22 12:20, N2MS wrote: InfoAge did accept my Radio and Electronic Data Books, Equipment Manuals and Electronic perodicals. I donated it in the spring of this year.
The person I worked with is Ray Chase. Is business card shows www.InfoAge.org his email address is radio862@...
Most of my Data Books were for semiconductor and integrated circuit devices. Among the periodicals accepted were my collection Popular Communications magazines.
They are selective on hardware donations but were actively looking for RADAR equipment. My guess, the ISEC folks but radar would be very appropriate for InfoAge & Camp Evans. A lot of work was done there from WWII until the 80's (maybe the 90's). The makerspace used to be called IXR - Institute for Exploratory Research. We still have the sign. If you have any documentation I would check with them before trashing it. Oh, so it was InfoAge - cool. Don't worry they're probably still around here. :-) We're very careful about tossing things. You never know what's appropriate. -- Linux Home Automation Neil Cherry kd2zrq@... Main site My HA Blog Author of: Linux Smart Homes For Dummies KD2ZRQ
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Re: How to use my NanoVNA-H4 to test resonant frequency of a tower?
On Tue, Nov 1, 2022 at 04:36 PM, WB2UAQ wrote: What if a number of insulated turns are wrapped
around the tower Well, that would have not only magnetic coupling but considerable capacitive coupling also with the wire wrapped around the tower. The resonant frequency of the magnetic and capacitive coupling could be a problem. You could minimize the capacitive coupling by standing the wire off some distance - an inch or several inches? - from the tower. Wish I had a structure to test this on. Try it on a street light pole or something. A stop sign post or a flag pole. the Tacoma Narrows (wasn't that Galloping Gurdy which mechanically
resonated?). Sure was! Have you seen the video of that?
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... So as to stay on the topic of Network Analyzers one piece of equipment Info-Age accepted was my General Radio 916 RF Bridge.
Mike N2MS
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On 11/02/2022 12:20 PM mstangelo@... wrote:
InfoAge did accept my Radio and Electronic Data Books, Equipment Manuals and Electronic perodicals. I donated it in the spring of this year.
The person I worked with is Ray Chase. Is business card shows www.InfoAge.org his email address is radio862@...
Most of my Data Books were for semiconductor and integrated circuit devices. Among the periodicals accepted were my collection Popular Communications magazines.
They are selective on hardware donations but were actively looking for RADAR equipment.
If you have any documentation I would check with them before trashing it.
Mike N2MS
On 11/02/2022 12:59 AM Neil Cherry <ncherry@...> wrote:
On 10/22/22 12:18, N2MS wrote:
... Fortunately InfoAge Museum in Wall NJ accepts technical documentation. ... Not InfoAge but more likely The Vintage Computer Federation (VCF - museum) or
NJARC (Antique Radio museum). I don't think we (Computer Deconstruction Lab -
CDL - Makerspace) got them. InfoAge manages the camp (Camp Evans) and the museums
are responsible for they're piece of the world. :-)
CDL has a NanoVNA-V2 for our digital ham equipment. NJARC has the boat anchors,
meant respectfully. ISEC has the 20m dish. Can you use the NanoVNA on a 20m
dish?
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InfoAge did accept my Radio and Electronic Data Books, Equipment Manuals and Electronic perodicals. I donated it in the spring of this year.
The person I worked with is Ray Chase. Is business card shows www.InfoAge.org his email address is radio862@...
Most of my Data Books were for semiconductor and integrated circuit devices. Among the periodicals accepted were my collection Popular Communications magazines.
They are selective on hardware donations but were actively looking for RADAR equipment.
If you have any documentation I would check with them before trashing it.
Mike N2MS
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On 11/02/2022 12:59 AM Neil Cherry <ncherry@...> wrote:
On 10/22/22 12:18, N2MS wrote:
... Fortunately InfoAge Museum in Wall NJ accepts technical documentation. ... Not InfoAge but more likely The Vintage Computer Federation (VCF - museum) or
NJARC (Antique Radio museum). I don't think we (Computer Deconstruction Lab -
CDL - Makerspace) got them. InfoAge manages the camp (Camp Evans) and the museums
are responsible for they're piece of the world. :-)
CDL has a NanoVNA-V2 for our digital ham equipment. NJARC has the boat anchors,
meant respectfully. ISEC has the 20m dish. Can you use the NanoVNA on a 20m
dish?
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On 10/22/22 12:18, N2MS wrote: ... Fortunately InfoAge Museum in Wall NJ accepts technical documentation. ... Not InfoAge but more likely The Vintage Computer Federation (VCF - museum) or NJARC (Antique Radio museum). I don't think we (Computer Deconstruction Lab - CDL - Makerspace) got them. InfoAge manages the camp (Camp Evans) and the museums are responsible for they're piece of the world. :-) CDL has a NanoVNA-V2 for our digital ham equipment. NJARC has the boat anchors, meant respectfully. ISEC has the 20m dish. Can you use the NanoVNA on a 20m dish? -- Linux Home Automation Neil Cherry kd2zrq@... Main site My HA Blog Author of: Linux Smart Homes For Dummies KD2ZRQ
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Re: How to use my NanoVNA-H4 to test resonant frequency of a tower?
In the 70's I worked at a transmitting station that had about 10 three wire 2 to 30 MHz "rhombic" field antennae fed with 600 ohm open wire feeders.On a whim one day I backed up my Celica fitted with a FT301D and home brew multi-band antenna mounted on the rear of the car, to the vertical section of the feeder of one of the field antenna.? As I approached the feeder, the whip coupled with the antenna as witnessed by the significant increase in a received signal was listening to on the 10 meter band.? The field antennae were not connected to any transmitters that day so all feeders were open at the feed point. This idea stemmed from a previous day walking along the boom of a Collins rotatable LPA (at 120 ft height) with a 27 MHz hand held used as a local engineering circuit.? At that time it was impossible to communicate with the ground due to the overpowering signals being received from Asian sources.I figured this was due to the coupling between the hand held and the RLPA - comms was OK at ground level. I was at the maximum coupling point at about half a meter from the feeder. So, I wonder if a vertical antenna parallel coupled to the tower would work? If it is possible to electrically connect a wire at the top of the tower and drop it down parallel to the tower thus forming a folded monopole and connecting the bottom of the wire to the VNA with the reference (earth) of the? VNA connected to the base of the tower would also work - you'd be able to identify resonance, just not necessarily at 50 ohms. Dino. ..? VK4BN (ex VK3IL) On Wed, 2 Nov 2022 at 9:59, Jim Lux<jimlux@...> wrote: On 11/1/22 4:36 PM, WB2UAQ wrote: Jim Allyn, I don't have a tower to test this idea.? I read the Notes on measuring tower resonances that you posted where Rudy couples to the tower with a rectangular loop.? What if a number of insulated turns are wrapped around the tower (tighter coupling than with a loop standing parallel to the tower) and the impedance looking into the loop is measured?? When the tower structure resonates the impedance should show a drop when energy is sucked out of the nanovna.? I am thinking this will happen if the tower is grounded or not.? ? Wish I had a structure to test this on.? \ I don't know that you want to wrap the coils *around* the tower.? You want them magnetically coupled - which is sort of challenging, since you'd normally have a magnetic core, the tower is "one turn", and your test coil is multiple turns. If you have a rectangular loop next to the tower, but "sticking out", the field from the closer wire couples more than the field from the farther wire, so you get some coupling (as an "air core transformer") much like some magnetic loop antennas do. I would think, too, that you could capacitively couple
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Re: How to use my NanoVNA-H4 to test resonant frequency of a tower?
On 11/1/22 4:36 PM, WB2UAQ wrote: Jim Allyn, I don't have a tower to test this idea. I read the Notes on measuring tower resonances that you posted where Rudy couples to the tower with a rectangular loop. What if a number of insulated turns are wrapped around the tower (tighter coupling than with a loop standing parallel to the tower) and the impedance looking into the loop is measured? When the tower structure resonates the impedance should show a drop when energy is sucked out of the nanovna. I am thinking this will happen if the tower is grounded or not. Wish I had a structure to test this on. \ I don't know that you want to wrap the coils *around* the tower. You want them magnetically coupled - which is sort of challenging, since you'd normally have a magnetic core, the tower is "one turn", and your test coil is multiple turns. If you have a rectangular loop next to the tower, but "sticking out", the field from the closer wire couples more than the field from the farther wire, so you get some coupling (as an "air core transformer") much like some magnetic loop antennas do. I would think, too, that you could capacitively couple
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Re: How to use my NanoVNA-H4 to test resonant frequency of a tower?
Jim Allyn, I don't have a tower to test this idea. I read the Notes on measuring tower resonances that you posted where Rudy couples to the tower with a rectangular loop. What if a number of insulated turns are wrapped around the tower (tighter coupling than with a loop standing parallel to the tower) and the impedance looking into the loop is measured? When the tower structure resonates the impedance should show a drop when energy is sucked out of the nanovna. I am thinking this will happen if the tower is grounded or not. Wish I had a structure to test this on. Maybe the resonant frequency of other structures could be measured the same way. How about the Golden Gate or the Tacoma Narrows (wasn't that Galloping Gurdy which mechanically resonated?).
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Hi Tom,
Nice job.
73...Bob VK2ZRE
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On 29/10/2022 2:59 am, Tom Thompson W0IVJ wrote: Hi Bob,
You are correct about the type of resistors to use for measurements.? I mostly use BNC cables and devices, so I have built cal standards and measurement standards using BNC connectors as shown in the attachment.? I have tried to make my measurements as close to the reference plane as possible.? The resistors I use are 0805 film resistors and the capacitors are 0805 ceramic for the most part.? Since most of my work is done at HF, the calibration tolerances are not as tight as for VHF and UHF.
Tom?? W0IVJ
On 10/27/2022 6:00 AM, Bob Ecclestone VK2ZRE wrote:
Hello Tom,
I noticed the format change just after I sent the post:-(
However the frequency difference was what caught my eye and I got "blind sided".
I agree with your comment, however, given other posts on component testing, defining a "pure resistance" is an interesting concept:-)
There was no mention of the test fixture or of resistor type, carbon, metal film or wire wound. A 10 ohm carbon film or wirewound resistor would have a very different response at 30Mhz compared to 1Mhz.
I repaired a piece of kit used to high voltage test sub station power transformers many years ago and it had a Philips 100 ohm 1 watt carbon resistor in series with the vertical input to the integrated CRO in the instrument.
The resistor was fried by a flash over and I was a bit puzzled at first because it was such a low series resistance in what was a high impedance input. I then twigged that it was, in fact, being used as a peaking coil.
Those Philips resistors had the carbon film deposited on the tubular ceramic substrate and then laser etched in a spiral to the required value. Lovely stable inductance!
However, the Smith Chart marker in the post is still on the real axis in both screenshots, negligible +j component. Like said, blind sided:-(
73...Bob VK2ZRE
On 27/10/2022 1:04 am, Tom Thompson W0IVJ wrote:
Hi Bob,
The issue was the values appearing on? S11(Smith chart) which DiSlord cleared up nicely.? By? the way, if you have the S11 port terminated in a pure resistance with no transmission line, the frequency makes no difference.? Even though the resistance is other than 50 ohms, the reading will be the same independent of frequency.
Tom?? W0IVJ
On 10/26/2022 7:00 AM, Bob Ecclestone VK2ZRE wrote:
Hi All,
I may have missed something here, but these screenshots are not comparing apples to apples.
In the first screenshot the marker is at 1MHz and in the second it is at 30MHz.
Given all the posts in this group about component testing and test fixtures, may I humbly suggest the "error" has more to do with marker frequency than software version.
73...Bob VK2ZRE
On 25/10/2022 8:06 pm, Tom Thompson wrote:
Here are the results of the two different firmware with a 10 ohm resistor attached to the S11 port.
Tom?? W0IVJ
On 10/24/2022 9:42 PM, DiSlord wrote:
Smitch chart marker value must be correct in all versions.
I think you select different smith marker format (Re+Im for example)
Provide screenshot
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Re: NanoVNA Saver - Display Smith Cart
Thanks Stan, I won't be so impatient on start up.
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Re: NanoVNA Saver - Display Smith Cart
It starts that way, and in some installations can take a very long time (two or three minutes or more the first time) as it unpacks and loads all of the necessary python environment (amd perhaps it has to time out on certain things as it loads). So if you wait a very long time, does it come up? It did on my computer, then it functioned just fine. It seems to come up faster (though still slowly) in subsequent start ups. Stan On Sat, Oct 29, 2022, 9:25 PM david.reed via groups.io <david.reed= [email protected]> wrote: I would add to the question about saver. I only get a command line box
when I download from nanoVNA saver to windows 11. Where can I find info
about getting the program to work?
Dave, AC0YW
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Re: NanoVNA Saver - Display Smith Cart
I would add to the question about saver. I only get a command line box when I download from nanoVNA saver to windows 11. Where can I find info about getting the program to work?
Dave, AC0YW
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Hugen,
I replaced R93 with a short and that fixed the problem.
Thank you,
Tom? W0IVJ
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On 10/28/2022 6:17 PM, Hugen wrote: On Sat, Oct 29, 2022 at 12:12 AM, Tom Thompson W0IVJ wrote:
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Thanks, Hugen,
Attached are two pictures of the area.? The board that does not write has a lot more circuitry around the SD card slot than the board that does write.? Should I just place a ferrite bead in place of R93?
Tom? W0IVJ
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On 10/28/2022 6:17 PM, Hugen wrote: On Sat, Oct 29, 2022 at 12:12 AM, Tom Thompson W0IVJ wrote:
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Re: NanoVNA Saver - Display Smith Cart
I updated. It works, Thanks
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On Friday, October 28, 2022 at 09:26:38 PM EDT, Stan Dye <standye@...> wrote: Charlie, all versions of nanovna-saver (that I am aware of) can show a Smith Chart. It just needs to be selected using the "Display setup..." button at the bottom left of the main screen. Near the bottom of the dialog window that comes up, there is a section titled "Displayed Charts", with 6 boxes to choose the up-to-six panels you want to display.? Clicking on each box will provide a list to choose from, including S11 Smith Chart, and lots of other options including "none". Setting the last two or 4 or five of the boxes to "none" will make the remaining charts larger. On Fri, Oct 28, 2022 at 5:41 PM Charlie N2MHS via groups.io <ucfargis1= [email protected]> wrote: ? What version do you have and where did it come from?Mine does not show
this.
? ? On Friday, October 28, 2022 at 11:58:35 AM EDT, Jim Lux <
jimlux@...> wrote:
? On 10/28/22 8:41 AM, Charlie N2MHS via groups.io wrote:
I can see the SMith Chart on my H4. Is there a way to see it on my PC (W11 64bit)
Doesn't Saver display it by default? Look at the button in lower left
for "Display Settings..."
Then, in the dialog, you can set the plot formats..
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Brent DeWitt
Jim Allyn - N7JA
