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Re: Antenna Queries de k3eui Barry prior to Nano VNA talk
A DC source has no complex portion and is not characterized by impedance,
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only the real term in the R ¡À jX. Further, if no current is drawn from the source, the presence of the R term isn''t there. The ¡À jX term requires AC and is absent for DC. However, once you draw a varying current from that DC source as in SSB or keyed RF (CW), then the complex portion appears. Example: Take AWG #000 (or whatever) large solid copper conductor. At DC, the cross sectional current density is homogenous. However, even at 60 Hz, skin effect due to resistance and inductance (+ jX) is evident and measurable. The cross sectional current density is no longer homogenous even at 60 Hz. Dave - W?LEV On Tue, Jul 6, 2021 at 9:53 PM Jim Lux <jim@...> wrote:
On 7/6/21 8:46 PM, Anne Ranch wrote:My favorite question , not directly related to nanoVNAantenna. --
*Dave - W?LEV* *Just Let Darwin Work* |
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Re: Any more "development " in bluetooth?
#bluetooth
NanoVNA-H/H4 contain free pins named as Rx and Tx (you can see pcb or scheme)
Exist connection modules like HC-05 or HC-06 It allow easy connect any device vs UART port over Bluetooth, device need only receive commands from UART port and answer to it Need only configure module and connect to PC, and use any software as on USB connection |
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Re: Any more "development " in bluetooth?
#bluetooth
Anne Ranch
Pardon my ignorance
I assume yours is software only solution. ( I did not read your posts in detail - so forgive me if it is there ) I see few posts "solder wire to ...." and I would prefer NOT to do that. I do have HC-06 somewhere... So to be idiotic - I now know I have nanoVNA-H and I can use dfu-util... What other info do I need to check first and then upgrade my firmware? BTW I did try "hold the multipurpose whee down then switch the power on" Same result flash of white screen then flash of logo then the screen goes crazy PS have been told l to search the forum , but I prefer most recent " been there , done that " interactions. With that said the hardware has USB connection to outside world functioning as "serial connection" now where do all these other therms come from ? TTL (transistor transistor logic ) ? UART (universal asynchronous RX TX ) that all looks as hardware "hackers" terminology, but I thought this is primarily a users group. |
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full 2 port measurements
I was thinking about how to make full two port measurements.? The easy way is to get a coax transfer switch.? But given how cheap the NanoVNA is (i.e. less than the cost of the relay), what about just getting two NanoVNAs and hooking them up back to back with coax T's.? that is hook Ch0 on one to Ch1 on the other, etc.
As long as the frequencies happen not to be synchronized, they won't interfere (or you could stop one, measure with the other, then swap). The input Z should be consistent (it's a resistor bridge or pad in both cases) and it would "calibrate out" |
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Re: Any more "development " in bluetooth?
#bluetooth
You can use my firmware, it allow connect to PC over any Serial TTL module
HC-05 or HC-06 Or use any WiFi to TTL Search this forum for more info |
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Any more "development " in bluetooth?
#bluetooth
Anne Ranch
When I joined this forum - abut a year or so ago - I also started
my CAT bluetooth project. Hence I asked few questions about if there are any plans to add bluetooth to nanoVNA. I actually went as far as finding STM processor with build in bluetooth. Then it kind-of died. So - are there any news as far as implementing bluetooth - without modifying the existing hardware ? |
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Re: DFU updating
#dfu
William Smith
It can be even twistier than that. Win10 re-enumerates every time you plug or unplug a device, any time you (re?)connect with RDP, any time any USB device goes to sleep or wakes up, and probably other events as well.
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This can play havoc with WSJT-x digital modes, because the audio port you were connected to, while it has the same name, is no longer connected, and needs to be disconnected and restarted. I wouldn't be surprised to learn that nanoVNA software has similar issues. 73, Willie N1JBJ On Jul 7, 2021, at 9:20 AM, Jim Lux <jim@...> wrote: |
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Re: DFU updating
#dfu
On 7/6/21 9:15 PM, Anne Ranch wrote:
Thanks, sure explains few things. When your PC boots it should re-enumerate all the USB devices. In Windows, you can force this in device manager (and there used to be a command line technique, as well, but I don't know if it exists in Win 10. It probably does, but some googling will be required to find it) The unit shows up as a com port and unless you're unlucky, you can probably figure out *which* com port by looking at the VID and PID of the USB device (or by unplugging and replugging, and seeing which com port disappears and reappears) As far as USB devices go, the NanoVNA has been pretty good. |
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Re: impedance test of a TV antenna, How do I adjust 50 ohm to 75 ohm
On Tue, Jul 6, 2021 at 09:10 AM, Jim Lux wrote:
Thanks for your reply. As I understood the question, the transformer was to be added as an aid for measurement. Yes, if it is part of the original setup, it would need to be included in the measurement and "rolled into the calibration.". Again, thank you, larry |
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Re: DFU updating
#dfu
Anne Ranch
Thanks, sure explains few things.
As I just posted elsewhere, I am ignorant about my toy version. ( And I am NOT taking it apart to find out... and I was just kidding about taking Polaroid of screen flash ) I am currently working on my version of bluetooth access to FT857 CAT and I am painfully aware how "screw up" any communication with PC can get. As far as USB - that is how it supposedly work - the USB device supposedly announce himself to the USB bus AFTER it gets thru its power-up. And if the USB bus , hence booting PC in this case, is not ready for it ...who knows what will happen next. In short - USB (standard) starts communication FROM USB device to whatever , not from whatever to USB device... Bluetooth is even messier. |
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Re: Antenna Queries de k3eui Barry prior to Nano VNA talk
On 7/6/21 8:46 PM, Anne Ranch wrote:
My favorite question , not directly related to nanoVNA Which breaks horribly if your source has very high or very low impedance - Consider a DC power supply. |
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Re: Further Confusion about nanoVNA versions
#firmware
On 7/6/21 8:33 PM, Anne Ranch wrote:
Forgive me if I get clumsy, but I am still trying to adjust to this forum.connect to it as a serial terminal, and send the "info" command or? "version" command info ¨C prints firmware info on console. Can be used to verify F/W build date. - This is similar the Version selection in the on-screen GUI menu Kernel: Compiler: Architecture: Core Variant: Port Info: Platform: Board: Build time: 4.0.0 GCC 7.2.1 20170904 (release) [ARM/embedded-7-branch revision 255204] ARMv6-M Cortex-M0 Preemption through NMI STM32F072xB Entry Level Medium Density devices NanoVNA Sep 19 2019 - 08:34:02 version ¨C returns simple version name and/or release ¨C Not the same as the GUI version command. See info command. eg: ¡°edy555 0.2.2 extended with scan command¡± or ¡°0.3.0m¡± I will dust off my old Polaroid to get a "selfie" of the flash so I can read it ...video as you boot, then single frame. I am NOT in favor of taking the hardware apart just to find the birthplace of the thing. |
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Re: Antenna Queries de k3eui Barry prior to Nano VNA talk
Anne Ranch
My favorite question , not directly related to nanoVNA
Why is having minimal SWR important ? Optional answer: SWR is an indicator of IMPEDANCE match between x and y devices - directly related to "power transfer" between. source - TX - and load - antenna. Demonstrate by applying Ohm's law. |
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Re: Further Confusion about nanoVNA versions
#firmware
Anne Ranch
Forgive me if I get clumsy, but I am still trying to adjust to this forum.
AT this point I am not concerned whose version I own. What bothers me - when the silly gizmo powers up I get a flash of info which I am assuming has the version in it somewhere.... I will dust off my old Polaroid to get a "selfie" of the flash so I can read it ... I am NOT in favor of taking the hardware apart just to find the birthplace of the thing. Very bad concept I learned whilst taking apart my parents alarm clock. ( Yes, I got the nanoVNA-saver working, still working - slowly - on DFU...) |
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Re: Further Confusion about nanoVNA versions
#firmware
Both companies came from the same people. They are the same. I have ran Deepelec firmware in mine for almost 2 years now with absolutely zero issues. I tried the latest version by sysjoint for $hits and giggles but felt like I took several steps backwards in doing so and flashed 1.0.2 from Deepelec again.
And it may be a very good possibility the same Gerber files were used in production as again both companies came from the same roots. Same packaging and everything, not sure if that was all a matter of convenience or both claiming it was their idea or what.... There's some info on that in the nanovna-f group if you dig back a ways |
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Re: Antenna Tuner with NanoVNA incorporated.
Anne Ranch
Now I am a firm believer in KISS concept.
There is nothing wrong with "show and tell " as you propose it. To be of practical use I assume you are going to use resonant antenna @ selected frequency. Further assume that you can vary the frequency not the size of the antenna. Either way - your nanoVNA will indicate that the antenna is too short or too long depending on frequency in use. It will give you corresponding values of parameters of your choice - nice, but still only show "out of resonance" to the average viewer. Perhaps you can come up with "gimmick" to involve the audience. "given current state of antenna - off resonance with such and such parameters as measured by nanoVNA - calculate the required adjustment in length to "tune it up". Just a crazy thought ... |
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Re: Further Confusion about nanoVNA versions
#firmware
An overall high level block flow diagram being "identical" does not mean they are "identical". In the RF world, since line widths, spacings, routing, vias, etc are all variables, I wouldn't assume they are "identical" unless the same Gerber files were used for both in production.
73 Kees K5BCQ |
Cory Ricci K9CDR
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