Re: How do you measure a car antenna?
"The operator of the exempted device shall be required to stop operating the device upon a finding by the Commission or its representative that the device is causing harmful interference. Operation shall not resume until the condition causing the harmful interference has been corrected."
So I guess you have to stop operating your electric vehicle...
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On 8/30/2023 10:41 AM, Frank Evans wrote: The operator of the exempted device shall be required to stop operating the device upon a finding by the Commission or its representative that the device is causing harmful interference. Operation shall not resume until the condition causing the harmful interference has been corrected.
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Re: How do you measure a car antenna?
Here's the exempted devices paragraph from Title 47, C.F.R. Part 15
============================================================
¡ì 15.103 Exempted devices.
Except as provided in paragraph (j) <(j)> of this section, the following devices are subject only to the general conditions of operation in ¡ì¡ì 15.5 <> and 15.29 <>, and are exempt from the specific technical standards and other requirements contained in this part. The operator of the exempted device shall be required to stop operating the device upon a finding by the Commission or its representative that the device is causing harmful interference. Operation shall not resume until the condition causing the harmful interference has been corrected. Although not mandatory, it is strongly recommended that the manufacturer of an exempted device endeavor to have the device meet the specific technical standards in this part.
(a) A digital device utilized exclusively in any transportation vehicle including motor vehicles and aircraft.
(b) A digital device used exclusively as an electronic control or power system utilized by a public utility or in an industrial plant. The term /public utility/ includes equipment only to the extent that it is in a dedicated building or large room owned or leased by the utility and does not extend to equipment installed in a subscriber's facility.
(c) A digital device used exclusively as industrial, commercial, or medical test equipment.
(d) A digital device utilized exclusively in an appliance, e.g., microwave oven, dishwasher, clothes dryer, air conditioner (central or window), etc.
(e) Specialized medical digital devices (generally used at the direction of or under the supervision of a licensed health care practitioner) whether used in a patient's home or a health care facility. Non-specialized medical devices, /i.e./, devices marketed through retail channels for use by the general public, are not exempted. This exemption also does not apply to digital devices used for record keeping or any purpose not directly connected with medical treatment.
(f) Digital devices that have a power consumption not exceeding 6 nW.
(g) Joystick controllers or similar devices, such as a mouse, used with digital devices but which contain only non-digital circuitry or a simple circuit to convert the signal to the format required (e.g., an integrated circuit for analog to digital conversion) are viewed as passive add-on devices, not themselves directly subject to the technical standards or the equipment authorization requirements.
(h) Digital devices in which both the highest frequency generated and the highest frequency used are less than 1.705 MHz and which do not operate from the AC power lines or contain provisions for operation while connected to the AC power lines. Digital devices that include, or make provision for the use of, battery eliminators, AC adaptors or battery chargers which permit operation while charging or that connect to the AC power lines indirectly, obtaining their power through another device which is connected to the AC power lines, do not fall under this exemption.
(i) Responsible parties should note that equipment containing more than one device is not exempt from the technical standards in this part unless all of the devices in the equipment meet the criteria for exemption. If only one of the included devices qualifies for exemption, the remainder of the equipment must comply with any applicable regulations. If a device performs more than one function and all of those functions do not meet the criteria for exemption, the device does not qualify for inclusion under the exemptions.
(j) Notwithstanding other provisions of this section, the rules governing certification apply to any equipment produced by any entity identified on the Covered List, as established pursuant to ¡ì 1.50002 of this chapter <>, as producing covered communications equipment.
======================================================================
Frank Evans
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On 8/30/2023 10:46 AM, Mike C. wrote: Hmmmm... so you'll be 'testing' while you're applying the brakes???
On 8/30/2023 10:58 AM, KENT BRITAIN wrote:
? Well, some of them kind of do.? ? ?Part of Dynamic Braking!
Kent
???? On Wednesday, August 30, 2023 at 09:14:21 AM CDT, Mike C.<mg@...>? wrote:
? ? EV's don't have "alternators". :0)
On 8/27/2023 5:52 PM, Rick Murphy wrote:
The AM radio in my car works just fine. Chevy BoltEV.
How short our memories are - does nobody else remember "alternator noise"?
Cars are mobile noise generators.
73,
?? ? ? -Rick
On Sat, Aug 26, 2023 at 9:47?PM N7RWB Craig Cherry via groups.io
<craig.cherry@...> ? wrote:
Ken, looking through FCC part 15 rules on emissions, I don¡¯t see any
exemption for electric car motors or power systems. Do you have a reference
to a FCC document for the exemption you mentioned?
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Re: How do you measure a car antenna?
Hmmmm... so you'll be 'testing' while you're applying the brakes???
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On 8/30/2023 10:58 AM, KENT BRITAIN wrote: Well, some of them kind of do.? ? ?Part of Dynamic Braking!
Kent
On Wednesday, August 30, 2023 at 09:14:21 AM CDT, Mike C.<mg@...> wrote:
EV's don't have "alternators". :0)
On 8/27/2023 5:52 PM, Rick Murphy wrote:
The AM radio in my car works just fine. Chevy BoltEV.
How short our memories are - does nobody else remember "alternator noise"?
Cars are mobile noise generators.
73,
? ? ? -Rick
On Sat, Aug 26, 2023 at 9:47?PM N7RWB Craig Cherry via groups.io
<craig.cherry@...> ? wrote:
Ken, looking through FCC part 15 rules on emissions, I don¡¯t see any
exemption for electric car motors or power systems. Do you have a reference
to a FCC document for the exemption you mentioned?
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Re: nano VNA-H will not connect via USB to control apps on Win10 - help please
1. Nanovna-H and Nanovna-H4 do not require a driver under Windows 10 to connect to Nanovna-app, etc. 2. So either there is some problem with your nanovna, the cable, or the computer. 3. I recommend first testing the nanovna/cable by using a friend's Win10 computer (no previous nanovna connection attempts). 3a. Open device manager 3b. Plug in usb cable to nanovna and computer (with nanovna off) 3c. Turn on nanovna. 3d. The device manager screen should update as the USB PnP detects the device 3e. It should appear under the "Ports (COM & LPT)" category as "USB Serial Device" 3f. When you turn off the nanovna, that same device should disappear from the list. 3g. If this does not happen, either the cable or the nanovna has a problem. 4. If the test in 3 works, your nanovna and cable are good, and there is something goofed up in your computer to diagnose. Which version of firmware is in your nanovnaa-H? It shouldn't matter, but would give us a frame of reference to help you. Stan On Wed, Aug 30, 2023 at 12:52?AM Brian Stokes <brianstokes@...> wrote: Hi Paul
There are no devices shown in gray. nanoVNA-QT can't see the device.
Instructions in say it needs a
driver. I installed CypressDriverInstaller_1.exe
Still doesn't work.
Thanks
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Re: How do you measure a car antenna?
Also, the older tube type car radios used vibrators and a transformer to
generate the necessary plate voltages for the tubes. Those vibrator
circuits generated some noise.
Zack W9SZ
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On Wed, Aug 30, 2023 at 9:58?AM KENT BRITAIN <WA5VJB@...> wrote: Well, some of them kind of do. Part of Dynamic Braking!
Kent
On Wednesday, August 30, 2023 at 09:14:21 AM CDT, Mike C. <mg@...>
wrote:
EV's don't have "alternators". :0)
On 8/27/2023 5:52 PM, Rick Murphy wrote:
The AM radio in my car works just fine. Chevy BoltEV.
How short our memories are - does nobody else remember "alternator noise"?
Cars are mobile noise generators.
73,
-Rick
On Sat, Aug 26, 2023 at 9:47?PM N7RWB Craig Cherry via groups.io
<craig.cherry@...> wrote:
Ken, looking through FCC part 15 rules on emissions, I don¡¯t see any
exemption for electric car motors or power systems. Do you have a reference
to a FCC document for the exemption you mentioned?
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Re: Not available at Ali Express / Zeenko
Same here. I've been very happy with it.
Zack W9SZ
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On Wed, Aug 30, 2023 at 9:51?AM Pirok-W4UNX <jason.pirok@...> wrote: Randl.com is where I got my H4.
On Wed, Aug 30, 2023, 09:24 KD2YYI <tim.sooley@...> wrote:
As someone who just got nanoVNA 4 from amazon I recommend following this
guide from nanovna.com to ensure you get a legit one that is firmware
upgradable.
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Re: USB vs no USB readings Plots change...
Back in the 70's I worked for GE testing yokes on TV's. The yokes had a couple of layers of #22 enameled wire etc... I say all this to open some ideas or complaints regarding using these yokes to do the decoupling of the USB? cable, just thinking..... (I was a technician)
Mike C. Sand Mtn GA
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On 8/29/2023 3:36 AM, Bob Ecclestone VK2ZRE wrote: Hello Mark,
I do not pretend to be an expert here, but I will make a few observations.
1. Many posts in this group have already noted that connecting a NanoVNA to a computer via USB cable results in an effective counterpoise being created which will change the tuning of the system under test.
2. Most professional VNAs are mains powered so you can not do a "battery vs USB" measurement comparison. Nothing to do with "laboratory grade" equipment.
3. Even professional grade battery operated VNAs have significant physical "bulk" compared to a NanoVNA so measurements will be disturbed less than those of the physically smaller sized NanoVNA.
4. Try measuring a 2M or 70cm hand held radio antenna fitted directly to the S11 port. Do the measurement holding the NanoVNA in your hand and with the NanoVNA sitting on a large cardboard box. You will notice a significant difference due to your body affecting the measurement.
So all I can suggest is fitting a ferrite to your USB cable to decouple it. Wind several turns through a large ferrite tube or toroid. Maybe one at each end.
I would suggest type 43 ferrite, but please, anyone with more knowledge here, please step in.
The main thing is you need to try to "kill" the counterpoise effect created by your USB cable.
HTH...Bob VK2ZRE
On 29/08/2023 3:07 am, Mark KQ4EKK wrote:
Thanks to all for their help with this.
Greg, it is not a bad connector,? I changed and tested all connection points, cables, etc. with identical and test units in order to remove those variables.? I always recalibrate for each set of tests.? I have removed all outside interference possibilities that I can.? I do not move anything near the unit, dont touch anything and just take notes on readings.? I attached two pics.? One with USB and one without, you can see the changes clearly.? The test rig is 2 identical built unun (haha, well as much as possible) in a back to back configuration.? The secondaries are connected and the the ground legs are connected.? The test is S21 thru displaying Smith and logmag.? I am able to wave hands over everything with no change, only when I touch something with a fingertip do I see changes (of course).? But it is overall stable.? When USB is connected it changes as indicated on pics.? It is not variable unless I change the usb source (laptop vs pc vs charger etc).? As you said, not a laboratory-grade instrument.? Understood.? I have not tested anything other circuits yet, only my current unun config since I noticed this, but I will shortly to see if it happens during other test and scales.? I just wanted to understand if anyone is seeing this.? Not concerned to much yet, but I usually do testing with the PC apps when working on bench and worried that I may have gotten errors in my old stuff worked on.
Francious, good to know.? I may just be running a sensitive test and I am hunting efficiency, so I am looking closely and these number changes and they reflect a lot of change in overall result.
Donald,? the test system hopping in could be quite possible.? I am testing the wire wrapped toroids with wires only into screw terminals to bnc and nanovna.. I am sure the connections are all good and solid while not optimum.? I was testing many configs to search for best results in turns and caps and toroid materials. Then I noticed the changes in traces and stopped testing in search of the problem (error introductions).? I just want to make sure that this is small issue and not a power circuit problem with my unit or a possible issue in the design of the power/charging system introducing these errors.? And how I can isolate my usb connection further.
thanks all!!
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Re: How do you measure a car antenna?
Well, some of them kind of do.? ? ?Part of Dynamic Braking!
Kent
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On Wednesday, August 30, 2023 at 09:14:21 AM CDT, Mike C. <mg@...> wrote: EV's don't have "alternators". :0) On 8/27/2023 5:52 PM, Rick Murphy wrote: The AM radio in my car works just fine. Chevy BoltEV.
How short our memories are - does nobody else remember "alternator noise"?
Cars are mobile noise generators.
73,
? ? ? -Rick
On Sat, Aug 26, 2023 at 9:47?PM N7RWB Craig Cherry via groups.io
<craig.cherry@...>? wrote:
Ken, looking through FCC part 15 rules on emissions, I don¡¯t see any
exemption for electric car motors or power systems. Do you have a reference
to a FCC document for the exemption you mentioned?
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Re: Not available at Ali Express / Zeenko
Randl.com is where I got my H4.
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On Wed, Aug 30, 2023, 09:24 KD2YYI <tim.sooley@...> wrote: As someone who just got nanoVNA 4 from amazon I recommend following this
guide from nanovna.com to ensure you get a legit one that is firmware
upgradable.
|
Re: How do you measure a car antenna?
EV's don't have "alternators". :0)
toggle quoted message
Show quoted text
On 8/27/2023 5:52 PM, Rick Murphy wrote: The AM radio in my car works just fine. Chevy BoltEV.
How short our memories are - does nobody else remember "alternator noise"?
Cars are mobile noise generators.
73,
-Rick
On Sat, Aug 26, 2023 at 9:47?PM N7RWB Craig Cherry via groups.io
<craig.cherry@...> wrote:
Ken, looking through FCC part 15 rules on emissions, I don¡¯t see any
exemption for electric car motors or power systems. Do you have a reference
to a FCC document for the exemption you mentioned?
|
Re: Not available at Ali Express / Zeenko
As someone who just got nanoVNA 4 from amazon I recommend following this guide from nanovna.com to ensure you get a legit one that is firmware upgradable.
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Re: Not available at Ali Express / Zeenko
I THINK you can buy the nano VNA 4 on Amazon.
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Re: nano VNA-H will not connect via USB to control apps on Win10 - help please
Hi Paul
There are no devices shown in gray. nanoVNA-QT can't see the device. Instructions in say it needs a driver. I installed CypressDriverInstaller_1.exe
Still doesn't work.
Thanks
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Re: nano VNA-H will not connect via USB to control apps on Win10 - help please
Hi Steve
yes, I have 4 cables, all check good using other devices
Thanks
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Re: nano VNA-H will not connect via USB to control apps on Win10 - help please
Hi Brian,
Have you tried a different USB cable?? I use the same cable that I use with my Android cell phone and it works perfectly.? I use Win 10 and I never had to install different drivers... NanoVNA connected right out of the box.? I'm not saying that this will absolutely solve your problem, but sometimes we jump to the conclusion that the problem is much more complicated and difficult than it actually is...? ; )
Good Luck!
Steve N0GWC
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On 8/29/23 8:32 PM, Brian Stokes wrote: I posted this query on Jul 17 #33483
There were no helpful replies.
I have tried installing every USB driver I can find for the nanoVNA but none of them makes the nanoVNA appear in the list of USB devices.
Have installed Cypress driver and 64 bit ST virtual COM port app.
No new COM ports appear when VNA is connected nor when virtual COM port app installed.
Device manager shows new 'Unknown USB device (device descriptor request failed)' when VNA-H is connected and powered up. Cable appears to be good since Device manager sees the VNA.
Tried several apps, VNA-QT, nanoVNA sharp 1.03, nanoVNAsaver, none will connect.
PC is Win 10.
Thanks for your help.
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Re: nano VNA-H will not connect via USB to control apps on Win10 - help please
I don't think you need to add any drivers on Win 10... (Pretty sure, I didn't, anyway. But it's been quite a while.)
You might try going into Device Manager, select View / Show Hidden Devices, and remove the hidden COM devices (they'll be shown in gray.) Disconnect your nanoVNA first...
You could even watch devices and you plugin your nanoVNA, and see what's actually going on. (It actually starts as a USB device, and the driver makes it into a COM device.)
Paul
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On 8/29/23 18:32, Brian Stokes wrote: I posted this query on Jul 17 #33483
There were no helpful replies.
I have tried installing every USB driver I can find for the nanoVNA but none of them makes the nanoVNA appear in the list of USB devices.
Have installed Cypress driver and 64 bit ST virtual COM port app.
No new COM ports appear when VNA is connected nor when virtual COM port app installed.
Device manager shows new 'Unknown USB device (device descriptor request failed)' when VNA-H is connected and powered up. Cable appears to be good since Device manager sees the VNA.
Tried several apps, VNA-QT, nanoVNA sharp 1.03, nanoVNAsaver, none will connect.
PC is Win 10.
Thanks for your help.
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nano VNA-H will not connect via USB to control apps on Win10 - help please
I posted this query on Jul 17 #33483
There were no helpful replies.
I have tried installing every USB driver I can find for the nanoVNA but none of them makes the nanoVNA appear in the list of USB devices.
Have installed Cypress driver and 64 bit ST virtual COM port app.
No new COM ports appear when VNA is connected nor when virtual COM port app installed.
Device manager shows new 'Unknown USB device (device descriptor request failed)' when VNA-H is connected and powered up. Cable appears to be good since Device manager sees the VNA.
Tried several apps, VNA-QT, nanoVNA sharp 1.03, nanoVNAsaver, none will connect.
PC is Win 10.
Thanks for your help.
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Re: NanoVNA for 120 ohm Twin wire Balanced lines
For large, high-Q coils, some crystal set builders use a styrofoam cake dummy like this:
Styrofoam is as close to air as anything solid I know of. It may be tedious to set up, but if you can support whatever you're measuring with fishing line you should be able to eliminate all support interaction. But you still have to worry about other stuff in the room. One time I was trying to accurately measure the Q of a large coil with my HP 4342A Q meter. I was astounded to find that I had to remove myself several feet and crouch down to eliminate interaction with my body. Even then I wasn't sure I got rid of it all. I couldn't read the meter from any farther away.
Brian
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Re: NanoVNA for 120 ohm Twin wire Balanced lines
On 8/29/23 1:55 PM, W0LEV wrote: Large styrofoam blocks are the "standard" in professional communities. At
home, with all the RF test equipment, I use either corrugated boxes or an
empty 50-gallon rubbish can. I could buy large styrofoam blocks from Hobby
Lobby (at least they used to carry them), but I'd have trouble storing them
with wifie.
We use blocks covered with static dissipative film (Amstat, etc.) The surface resistance is sufficiently high that it doesn't load the RF system, but it also prevents the charge that inevitably accumulates on foam from destroying your electronics.
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Re: NanoVNA for 120 ohm Twin wire Balanced lines
Large styrofoam blocks are the "standard" in professional communities. At
home, with all the RF test equipment, I use either corrugated boxes or an
empty 50-gallon rubbish can. I could buy large styrofoam blocks from Hobby
Lobby (at least they used to carry them), but I'd have trouble storing them
with wifie.
Dave - W?LEV
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On Tue, Aug 29, 2023 at 7:56?PM Brian Beezley <k6sti@...> wrote: Corrugation should lower the dielectric constant and loss of any material
roughly in proportion to its air content. So corrugated cardboard should
have better specs than the uncorrugated cardboard specs I quoted. However,
the electric field of the object under test will be maximum where it
touches the support. It's there where the dielectric properties of the
support matter. Increasing the size of a supporting box is unlikely to
reduce the effect of lossy box material.
Using lossy materials with high dielectric constant is fine for casual
measurements. But it pays to use something more transparent to electric
fields when the measurement is important. This also applies to the magnetic
field. Avoid anything ferromagnetic or conductive nearby.
Brian
-- *Dave - W?LEV*
--
Dave - W?LEV
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Mike C.
Paul - AI7JR