Keyboard Shortcuts
ctrl + shift + ? :
Show all keyboard shortcuts
ctrl + g :
Navigate to a group
ctrl + shift + f :
Find
ctrl + / :
Quick actions
esc to dismiss
Likes
- Nanovna-Users
- Messages
Search
Re: TinyPFA
Yes, these are the internal reference limits, only relevant when you measure against the internal reference
For phase noise measurements you should always use an external reference -- NanoVNA Wiki: /g/nanovna-users/wiki/home NanoVNA Files: /g/nanovna-users/files Erik, PD0EK |
Re: NonoVNA App for Win10
Hi Sam,
The latest Version 1.1.215 from DiSlord, dated 29-May-2023, works fine on my Windows 10 installation. You should be able to find it here: Click on the link on the third row down for ¡®NanoVNA-App.exe¡¯. That should take you to a new page. You can either click on the link for ¡®View raw¡¯ or on the ¡®Download raw¡¯ link at the far right side of the light gray line ¡®Code¡¯ line. Alternately, here¡¯s a direct link that should download the file: Good luck. Ken -- WB?OCV From: Sam Reaves Sent: Saturday, August 5, 2023 02:38 PM To: [email protected] Subject: [nanovna-users] NonoVNA App for Win10 Is there a version of the NanoVNA App available for Windows 10? When I try to install the version that I have Win10 complains in a big blue banner "This App can't be run your PC". I have tried compatibility and run as administrator mode without success. Thanks! |
Re: TinyPFA
See the slide on measuring phase noise almost at the end of this presentation
-- NanoVNA Wiki: /g/nanovna-users/wiki/home NanoVNA Files: /g/nanovna-users/files Erik, PD0EK |
Re: TinyPFA
If you take a VCO under test and phase lock it to an appropriate XO and use that XO to input to the PFA. Can you obtain close in PN as well via the Allen variance close in and then from a time jitter the PN at some offset, say 1 kHz?
I have a test for far offsets but limited on close in PN. Alan |
Re: TinyPFA
It depends on the accuracy you need
For 1e-13 accuracy the two input frequencies (could be harmonics) have to be within 0.5 Hz of each other. If 1e-10 is sufficient accuracy you can first calibrate the internal TCXO of the tinyPFA with a GPSDO or other reference and than measure a source at any frequency between 100kHz and 300 MHz against the calibrated internal TCXO. It should even be possible to measure at a harmonic of this range. -- NanoVNA Wiki: /g/nanovna-users/wiki/home NanoVNA Files: /g/nanovna-users/files Erik, PD0EK |
Re: Different SWR readouts between NanoVNA-H and NanoVNA Saver
I have a NanoVNA-F and went through the calibration process and then was measuring a few of my HT antennas to get comfortable with the VNA. I noticed very different readings if I held the VNA with two hands, one hand, and not touching it on a wooden surface. Is there a specific way to hold or not hold the VNA when doing measurements? Do you need to ground it?
I was getting values like 1.3 with two hands, 1.5 - 2.3 with left or right hand, and 3+ with it resting on a wood table. Brian W1BKW |
Re: Static Energy and Is This the Correct Group?
#newbie
#beginners1
#general_vna
On Fri, Aug 4, 2023 at 06:34 PM, Ken Sejkora wrote:
Not if the transformer has continuity between inner and outer conductors, but it only takes a second, cultivates a good habit and will do no harm. 73, Don N2VGU |
Re: FONT? and 2 other ?s - NanoVNA-H 4
Fonts size, not possible change (or need more work for UI and text position and sizes)
Remember state (select and save config) allow save several state (like freq range, bandwidth, points count, options) while device power off (but battery present). SD card better format in FAT32, for LiteVNA and Card reader mode better set bigger sector size (32-64k) this allow more faster read file structure from card and see card data. H4 and Lite also support ExFAT filesystem. |
Re: Double Discone VSWR
On Thu, Aug 3, 2023 at 11:33 PM, John Nightingale wrote:
Interestingly I cannot confirm that coax cable necessarily degrades over time! Of course, if cable gets waterlogged, it will degrade. But properly used, which means avoiding water ingress, it can last for a very long time. I sometimes measure the loss of the various transmission lines in my station, and even a long piece of RG8, that is over 40 years old, still meets its specs! It's right that I wouldn't buy a used flea-market-special cable without thoroughly checking it. But I would also not disregard it as being certainly bad. If the price is good, and I need it, I would test it, and buy it if it's still fine. It's easy enough to take the NanoVNA to the hamfest! Yes, that error happens to many hams. I remember one who asked me to check why he couldn't hit the local UHF repeater. His radio and antenna were both new, he said, and the SWR was fine. I went to his place. He lived in a second floor of a 22 story building, had run an RG58 feedline through a ventilation shaft all the way to the roof, and installed his antenna there - and there was a solder short in his coax connector at the upper end of the cable. The SWR, as measured at his second floor shack, was absolutely great... To be fair, I have to mention that he was a new ham. But many hams have real trouble understanding that the more lossy the coax cable is, the better will the SWR be, and that's still not a good idea to use bad cable to improve the SWR! |
Re: Static Energy and Is This the Correct Group?
#newbie
#beginners1
#general_vna
Hi Don,
I agree ¨C always a good practice to short center conductor and shield together before connecting to an instrument. Even better is to short them together and connect the shorted junction to an earth ground. I try to do that whenever possible. As you point out, coax has an inherent capacitance, and considerable breakdown voltage, so a long run of coax can store up a considerable charge, especially when terminated to a well insulated wire antenna. However, just for the sake of argument and to exercise the neural muscles, is it necessary to do so if you have a balun or unun between the antenna and coax? I would think both would shunt any static charge to ground unless you had a true galvanic isolation configuration, with no electrical coupling between the primary and secondary of the coupling transformer. Not likely in a transmitting antenna, but who know. Again, I¡¯m not disputing your comment. I¡¯m just trying to promote understanding, including mine, of antenna configurations. Regardless, it is still an invaluable practice to short center-to-shield before measuring, just to prevent any unforeseen failures on a known configuration. Ken -- WB?OCV From: Donald S Brant Jr Sent: Friday, August 4, 2023 05:51 PM To: [email protected] Subject: Re: [nanovna-users] Static Energy and Is This the Correct Group? #newbie #beginners1 #general_vna On Fri, Aug 4, 2023 at 02:13 PM, Peter N0PGM wrote: This is good practice before connecting any cable to any instrument. I usually short the inner and outer conductors against the outer conductor of the connector to which it will be attached; I wouldn't use my hand, especially with an antenna feedline which may be quite long and hold a considerable charge which could pack a wallop. 73, Don N2VGU |
Re: TinyPFA
On 8/4/23 2:42 PM, W0LEV wrote:
Thanks, David, for answering my question. So the reference must be quite You might wait for Erik to weigh in. I don't know that it wouldn't work with appropriately harmonically related frequencies. I suppose it sets the receive LO, and the back end only has a few kHz BW. But if you had a 10 MHz and a 20 MHz, it might work, since you'd be beating the 2nd harmonic of the LO for the 20, and the first harmonic for the 10. But this is also why you see a lot of folks rigging up various and sundry programmable dividers to get it down to 1 pps, which you can compare with TAPR TICC or similar - For ADEV, anyway. And tons of emails over the years on the time-nuts list about how to make this or that measurement, where you don't want the measurement system to degrade the measurement (after all, that divider isn't noise free!) - you know, when you're comparing your cryogenic sapphire resonator against your active hydrogen maser in the garage. Dave - W?LEV |
Re: Static Energy and Is This the Correct Group?
#newbie
#beginners1
#general_vna
On Fri, Aug 4, 2023 at 02:13 PM, Peter N0PGM wrote:
This is good practice before connecting any cable to any instrument. I usually short the inner and outer conductors against the outer conductor of the connector to which it will be attached; I wouldn't use my hand, especially with an antenna feedline which may be quite long and hold a considerable charge which could pack a wallop. 73, Don N2VGU |
Re: TinyPFA
Thanks, David, for answering my question. So the reference must be quite
toggle quoted message
Show quoted text
close to the measured frequency. Won't work with my 10 MHz GPS reference. Of course, I have several signal generators, but none as good as the GPS referenced 10 MHz. Dave - W?LEV On Fri, Aug 4, 2023 at 8:45?PM David McQuate <mcquate@...> wrote:
I believe that the maximum frequency difference between the PFA's two-- *Dave - W?LEV* --
Dave - W?LEV |
Re: TinyPFA
I believe that the maximum frequency difference between the PFA's two
toggle quoted message
Show quoted text
inputs in 200 Hz (not kHz or MHz), so the two signals you are comparing must be very close in frequency. Dave - WA8YWQ On 2023-08-04 13:25, W0LEV wrote:
So if I have a GPS reference of a couple of parts in 10^13, that will be my-- *Dave - W?LEV* --
Dave - W?LEV |
Re: TinyPFA
So if I have a GPS reference of a couple of parts in 10^13, that will be my
toggle quoted message
Show quoted text
accuracy, and only at 10 MHz output from my GPS "clock"? With the 10 MHz reference from GPS, will it measure ADEV on other non-10 MHz frequencies (I'm thinking of DTV unmodulated carriers and HF signals off the ionosphere)? In the past for DTV carriers, I've dumped my 10 MHz GPS referenced output into a comb generator and picked the tine which is closest to the DTV carrier. That is selected on the a spectrum analyzer which is then zeroed to the tine. Then I measure the frequency of the DTV carrier. The measurement is "sort'a" referenced to the 10 MHz GPS derived output through the comb generator. Not perfect, but it gets me down to 0.001 Hz. Dave - W?LEV Dave - W?LEV On Fri, Aug 4, 2023 at 7:36?PM Erik Kaashoek <erik@...> wrote:
On Fri, Aug 4, 2023 at 10:56 AM, W0LEV wrote:--GPS. *Dave - W?LEV* --
Dave - W?LEV |
Re: Static Energy and Is This the Correct Group?
#newbie
#beginners1
#general_vna
The coax cable capacitance stores up a charge and if you short the ends of the coax together you discharge it. When shorted you can also touch the terminals to ground of you want to be really cautious.
Roger |
Re: TinyPFA
On Fri, Aug 4, 2023 at 10:56 AM, W0LEV wrote:
The tinyPFA can measure the phase difference of two 10MHz signals with 1e-13 accuracy in one second Its accuracy and resolution is better than any of the big timer/counters but less then the phasestation devices. It's sole purpose it to measure frequency stability or ADEV of one source against another source -- NanoVNA Wiki: /g/nanovna-users/wiki/home NanoVNA Files: /g/nanovna-users/files Erik, PD0EK |
to navigate to use esc to dismiss