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Okay wait, I see what's going on here. The frequency graduations don't really match the labels. What I took to be a vertical line at what is labeled 146.2 MHz is really lower than that frequency, assuming the frequency axis is truly linear (yes, Saver is set for linear).

Well, that was confusing. Thanks anyway Stan.

Hi and thanks for getting back to me...

On Sat, Aug 26, 2023 at 04:33 PM, Stan Dye wrote:

Note that the markers in nanovna-saver and the nanovna display are set
independently. Did you manually set those specific marker values in
Saver? Or were they automatically set by saver?

I manually set the markers in VNA Saver to match the markers set on the VNA - double checked this a bunch of times.

Do the marker values on
the Saver data display screen match the ones you see, or the ones you typed
into this message?

Marker settings everywhere match. See attached screen capture of entire Saver window. Markers 1 and 3 appear pulled towards the center relative to the frequency axis markings.

Also attached is a GetScreenSE capture of the NanoVNA screen, the markers and graduations line up perfectly as expected.

Saver's algorithm for setting the bandwidth markers for
the highpass may not be identical to the algorithm on the nanovna itself,
so it would not be surprising if they did not exactly match.

I'm not sure I follow that. I know that some values start/stop will cause the marker frequency settings to move off of what I try to set them to. However, this does not appear to be the case or the markers I used with the sweep span at 1 MHz. The markers stay put where I entered them. Is this what you are referring to?

In any case, the spots where the makers *appear* on Saver's frequency axis are so far off as to be a real problem IF that's where the makers really were. I'm relying on the markers being where the maker settings say they are. If that can't be achieved, thenI'll need to find some other gear to tune duplexers. ?\_(ツ)_/?

Take it back to the dealer and insist that they fix the problem.

The problem is poorly designed and implemented inverters for the battery and electronics.
It probably does not meet part 15 FCC rules for unintentional radiators.

Glenn

--
-----------------------------------------------------------------------
Glenn Little ARRL Technical Specialist QCWA LM 28417
Amateur Callsign: WB4UIVwb4uiv@... AMSAT LM 2178
QTH: Goose Creek, SC USA (EM92xx) USSVI, FRA, NRA-LM ARRL TAPR
"It is not the class of license that the Amateur holds but the class
of the Amateur that holds the license"

Note that the markers in nanovna-saver and the nanovna display are set
independently. Did you manually set those specific marker values in
Saver? Or were they automatically set by saver? Do the marker values on
the Saver data display screen match the ones you see, or the ones you typed
into this message? Saver's algorithm for setting the bandwidth markers for
the highpass may not be identical to the algorithm on the nanovna itself,
so it would not be surprising if they did not exactly match.

On Sat, Aug 26, 2023, 2:20 PM Larry Mollica AD6G <auubtab4b8@...>
wrote:

Sorry if this has been addressed already. I've made attempts to find some
discussion of this here but so far unable to track it down.

The frequency axis in NanoVNA saver (0.3.10-Win7, same for 0.3.8) & Python
3.7.9 appears to not agree across the graph with the markers. Please see
attached (High pass after.png). The frequency axis & markers appear correct
on the NanoVNA screen, they only disagree in NanoVNA Saver.

Markers:
1 = 146.19 MHz
2 = 146.5
3 = 146.79

Note that marker 1 appears to the right the graph's 146.2M. Marker 2 is
correct. Marker 3 is to the left of where it should be.

Is there some way to correct this? Thanks

You set me on the right path, Dragan. I went ahead and found the latest firmware for the Nanovna classic (not H), version 0.8.0, and it worked ok so I'll stick with that.

It is interesting that nobody else has reported any trouble getting the Nanovna classic to work with the DisLord H versions of the software. Probably something I'm doing but I'm going to leave well alone!

Sorry if this has been addressed already. I've made attempts to find some discussion of this here but so far unable to track it down.

The frequency axis in NanoVNA saver (0.3.10-Win7, same for 0.3.8) & Python 3.7.9 appears to not agree across the graph with the markers. Please see attached (High pass after.png). The frequency axis & markers appear correct on the NanoVNA screen, they only disagree in NanoVNA Saver.

Markers:
1 = 146.19 MHz
2 = 146.5
3 = 146.79

Note that marker 1 appears to the right the graph's 146.2M. Marker 2 is correct. Marker 3 is to the left of where it should be.

Is there some way to correct this? Thanks

That’s great. Come up with a technology like EVs that appear to exempt from FCC interference standards, and make it ‘acceptable’ because it’s “…good for the environment…”. Any other electronics manufacturer would likely have to modify THEIR equipment so as to meet FCC requirements and not interfere with the radio spectrum. However, in this case it appears Electric Vehicle manufacturers are exempt from FCC interference standards, and as a result an entire broadcasting medium (AM broadcasting) is sacrificed and made to be obsolete. Nearly-gone are the days of AMBCB DXing, and pulling in stations from thousands of miles away. I’m a dying breed.

If one had conspiracy theorist tendencies, one might wonder if the action is deliberate so the 530 to 1710 kHz spectrum can be “freed up” and offered to the highest bidder for other purposes.

So much for my rant. Everyone have a great weekend.

Ken

From: BryonB
Sent: Saturday, August 26, 2023 01:54 PM
To: [email protected]
Subject: Re: [nanovna-users] How do you measure a car antenna?

Most of the biggest stations on the AM broadcast band around here are also
simulcasting on the FM band and internet streaming now. They probably saw
the trend happening in car radios before I did.

It seems like there's a big push to get everyone to "stream" all their
content online in North America now though.

So if you're missing your AM station in the car and they don't simulcast on
FM you may have to resort to either using a portable AM receiver (and
discover if EV noise is in fact the real reason it's no longer there), or
stream the station online.

I personally stopped listening to political talk radio a few years ago and
my blood pressure and anger management are both much better now. ??

My NanoVNA-F did help with tuning my dual-band mag-mount antenna on the car
though. I wasn't looking to measure actual impedances with any precision
though, just finding the low SWR tuning points. Because the mag mount
antenna has the RG-58 coax cable directly attached, it would have been
difficult to calibrate out that 15 feet or so of coax without taking it
apart or making up another coax piece with the same type coax.


--
--Bryon, NF6M

Most of the biggest stations on the AM broadcast band around here are also
simulcasting on the FM band and internet streaming now. They probably saw
the trend happening in car radios before I did.

It seems like there's a big push to get everyone to "stream" all their
content online in North America now though.

So if you're missing your AM station in the car and they don't simulcast on
FM you may have to resort to either using a portable AM receiver (and
discover if EV noise is in fact the real reason it's no longer there), or
stream the station online.

I personally stopped listening to political talk radio a few years ago and
my blood pressure and anger management are both much better now. ??

My NanoVNA-F did help with tuning my dual-band mag-mount antenna on the car
though. I wasn't looking to measure actual impedances with any precision
though, just finding the low SWR tuning points. Because the mag mount
antenna has the RG-58 coax cable directly attached, it would have been
difficult to calibrate out that 15 feet or so of coax without taking it
apart or making up another coax piece with the same type coax.


--
--Bryon, NF6M

To further W0LEV’s point, a good friend of mine works for that manufacturer, specifically on that truck, and said that the EMI from the PWM controllers in powertrain and battery management system was a large consideration for the decision to disable AM on the radio stack. Additionally the radios are now SDR based and have highly sensitive basically wide open RF front ends.

My personal experience is that EV manufacturers struggle with EMI, some more than others. I’ve been totally “blown off the air” on 10m by a passing Rivian truck. I also know several hams with Tesla vehicles who don’t seem to be plagued by this issue. YMMV...

In my own truck, RAM 1500, a simple aftermarket upgrade has caused a mess of EMI while the engine is running. Who would have thought those performance coil packs would cause so much noise!!!

Anyway, I run the risk of diverting too far from the original post for this thread..

Larry, the central pin “is” the resonant element, as compared to the baofeng antenna. The body of the vehicle is the ground plane. So in measuring that antenna, you could unplug it from the radio stack where both conductors are present and use some sort of adapter to make the connection to your nanovna. A measurement of an antenna system should include the transmission line as well, right? By comparison, the baofeng antenna outer shield connects to the radio body and capacitively to your hand to make the ground plane. (or via a tiger tail, but that’s a different discussion)

For a receive only antenna, the impedance match is not super important. These antenna are all compromise antenna and suffer accordingly. The nanovna will provide data points for impedance etc., but its not very helpful for understanding the difference in reception. Furthering what W6PAP said, for receive you are best served by an S-meter or a spectrum analyzer. Heck you might actually be able to quantify potential EMI frequencies with the truck “on” verses “off” with the analyzer.

For some things to check, verify that the body panel the antenna is mounted on is properly bonded to the rest of the vehicle. Bad ground = poor ground plane. That can change the dynamics of the antenna for certain. Hope that helps and have a great day!

-Ben

But it will do business with PayPal?

Lester B Veenstra K1YCM M?YCM W8YCM 6Y6Y W8YCM/6Y 6Y8LV (Reformed USNSG CTM1)
lester@...

452 Stable Ln
Keyser WV 26726 USA

GPS: 39.336826 N 78.982287 W (Google)
GPS: 39.33682 N 78.9823741 W (GPSDO)


Telephones:
Home: +1-304-289-6057
US cell +1-304-790-9192
Jamaica cell: +1-876-456-8898

My credit card issued on my credit union will not do business with
AliExpress. Wonder why? Three guesses and the first two don't count......

Dave - W?LEV


On Sat, Aug 26, 2023 at 4:55?PM Donald S Brant Jr <dsbrantjr@...>
wrote:

Ali Express is on my s**t list too, after one of their vendors shipped the
wrong product (Hantek o'scope) and, after shipping it back on my dime and
two months of wrangling to get the right item they refused to reimburse
shipping.
Fool me once, shame on you, fool me twice.......
73, Don N2VGU

--

*Dave - W?LEV*


--
Dave - W?LEV

If you are describing a problem with AM reception, it could be EMI from all of the inverters, etc. in the car, interfering with reception, rather than an antenna issue. I had heard that car makers were trying to move away from having AM to side step this issue. 73, Don N2VGU

Ali Express is on my s**t list too, after one of their vendors shipped the wrong product (Hantek o'scope) and, after shipping it back on my dime and two months of wrangling to get the right item they refused to reimburse shipping.
Fool me once, shame on you, fool me twice.......
73, Don N2VGU

That's a great thought, unfortunately, I haven't had luck with two disputes using PayPal.
In my case it seemed to come down to a "my word versus theirs thing.
The problem was difficult to prove using words and imagery. Because of that, no matter if I'm dealing with Ali, Banggood, or others, my spending limit all continue to be USD 25 (or so). Those stores are so far away it's not worth my risking shipping costs if they will exceed the replacement costs.

It is generally believed that the move to eliminate? AM radios in? cars is political not technical .Most conservative programs are on the AM radio band.

The 4-Runner was a standard internal combustion engine. The Ford Lightning
is an EV. With the EV's comes a massive amount of RFI. It's so bad that
manufacturers are eliminating AM radio from their vehicles.

I'd venture a guess the problem is not with the antenna, but with the EV
technology in general.

Dave - W?LEV

On Sat, Aug 26, 2023 at 1:22?PM Lawrance A. Schneider <
llaassllaaass@...> wrote:

Enclosed is the photo of a car antenna's mounting. Note it is a single
pin. Also enclosed is a picture of my Baofeng's antenna post. Note that
the car antenna is a single post/pin. The Baofeng's antenna has a pin
inside a mounting. Thus, to measure the Baofeng's antenna you simply
connect it to the nanavna. How to do the car antenna???

The reason I ask is experience with my old Toyota 4Runner's radio and my
new Ford Lightning's radio. The 4Runner radio would work 50 to 80 miles
from a tower. The Lightning will start to fade 20 miles from the same
towers. Is the fault with the antenna or the radio???

Thank you for any cogent answer. larry

--

*Dave - W?LEV*


--
Dave - W?LEV

Hi, Larry,

Note that measurements with a VNA will examine the impedance presented by the antenna as a source but not its efficiency at receiving signals. If you compare two antennas, you might see a better impedance match with one, but a higher level incoming signal from the other.

If you have the ability to connect an external radio with an S-meter or signal level indication of some kind (maybe a spectrum analyzer), you might try that with both vehicles to see how much signal is arriving via each antenna. That, combined with the VNA readings, might give you some idea of how each antenna is performing.

Note that short receiving antennas are often not impedance matched to their receivers. Even if they are, the impedances of the antenna and the receiver may be much higher than 50 ohms so you might see a really high SWR, against 50 ohms, from a properly operating antenna.

73,

Maynard
W6PAP

Or use PayPal which offers a better level of protection than dealing directly with AliExpress.

Lester B Veenstra K1YCM M?YCM W8YCM 6Y6Y W8YCM/6Y 6Y8LV (Reformed USNSG CTM1)
lester@...

452 Stable Ln
Keyser WV 26726 USA

GPS: 39.336826 N 78.982287 W (Google)
GPS: 39.33682 N 78.9823741 W (GPSDO)


Telephones:
Home: +1-304-289-6057
US cell +1-304-790-9192
Jamaica cell: +1-876-456-8898

I had the same problem with Aliexpress not taking my card. I think they view it as stolen or bogus and you need to call them and clear it up (Ha, Ha). I fixed the problem by opening a new account and using a different card.
Gary
W9TD

Here's a document of vehicle rear window antenna concept: