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Re: Saver software - Offest Delay seems inoperative
Op 12-5-2022 om 04:03 schreef Rich NE1EE:
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On 2022-05-11 18:20:-0700, you wrote:I am using NanoVNA Saver 3.10. Offset delay works for me.Thanks for the update...It might be related to Saver version, because 0.4 is the latest...and it might be related to -H4 firmware version...what are you running? |
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Re: Saver software - Offest Delay seems inoperative
On 2022-05-11 18:20:-0700, you wrote:
I am using NanoVNA Saver 3.10. Offset delay works for me.Thanks for the update...It might be related to Saver version, because 0.4 is the latest...and it might be related to -H4 firmware version...what are you running? |
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Re: Saver software - Offest Delay seems inoperative
On Wed, May 11, 2022 at 09:02 AM, Ralph Gable wrote:
I am using NanoVNA Saver 3.10. Offset delay works for me. I calibrated my NanoVNA-H4 device (Not in Saver) from 50 kHz. to 300 MHz. and then attached a 12 inch cable to CH0 (Port 1). You can see the result on the Smith Chart. Then added an offset delay to de-embed for the cable. Smith Chart now shows an open at far right of Smith chart. Roger |
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Re: Saver software - Offest Delay seems inoperative
On 2022-05-11 15:46:+0000, you wrote:
However, the Saver software ...Maybe nothing :-) There are some things in Saver that don't work well. I havna tried this approach, but have applied e-delay on my -H4, and it works as expected. I take two approaches to using remote software. 1. Cal the device, including e-delays, and tell the software to use that cal data, even if I use multiple sweeps. 2. Reset the device, so that there is no cal, then do the cal in software. It might be that this is the only way the Offset Delay can be applied. Please try that...and let us know. I assume from the lack of responses that no one reading so far, I included, know the answer, and I am not set up to run a test. ~R~ |
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Re: suggestion on open new topics
1 - Keeping topics fresh and to the point enhances the groups.io Message Search function.
2 - I lock my group topics after 20 days. (By the end of 10-15 responses, almost every thread gets hijacked to a different topic. 3 - groups.io provides a number of ways to access messages, including digests, emails and online and they do work differently. Larry AC9OX |
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Re: suggestion on open new topics
On Tue, May 10, 2022 at 11:36 PM, Maurizio IZ1MDJ wrote:
When a topic has not had any posts for a period of time (months or years) it is better to start a new topic. Posting to the old topic is considered "necroposting" and is discouraged in most groups. Roger |
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Re: suggestion on open new topics
groups.io does not offer the full capabilities of an actual "forum"
software where you can properly categorize content. While those are ideal, to have the best function and access it would require significant funding to get on an AWS or other platform. The amount of traffic this listserv gets would require higher data packages. On Wed, May 11, 2022 at 10:14 AM va3rr via groups.io <va3rr= [email protected]> wrote: Many groups.io users receive their content via email listserv. While I-- Eric M. Gildersleeve ~ KD7CAO Google Voice: 940-784-3029 |
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Re: suggestion on open new topics
On 2022-05-10 23:36:-0700, you wrote:
Hi to allI am on another forum where we have created topic posts, and those posts are only links to message threads about that topic. Anyone can add to the topic post thread. For example, here we might have threads that address measuring the length of coax, or adjusting the calibration plane with e-delay. Part of the difficulty will be that folks hijack threads, so a thread might have a subject of "adjusting the calibration plane with e-delay." and the subject really be about measuring with tweezers! ;-) No specific criticism intended...I just grabbed 2 ideas from recent posts. ~R~ 72/73 de Rich NE1EE The Dusty Key On the banks of the Piscataqua |
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Re: nanoVNA Tweezer L/C Measurement Accuracy Examples
Tom,
Thank you for taking the time to make your post. In particular I noted the following: - The calculated inductance of your 4.7 uH inductor varied from 4.56 to 4.82 uH _(+2.5 to -3%) over a wide reactance range of +j15 to +j443 - The calculated inductance of your 100 nH inductor varied from 98.04 to 100.74 uH _(+.7 to -.2%) also over a wide reactance range of +j2 to +j94 - The calculated capacitance of your 4.70 pF capacitor varied from 4.51 to to 4.62 pF _(-4%) over an extremely wide reactance range of -j1.5 to -j11,788 Very nice test results. It shows how a good test jig can accurately measure inductors and capacitors. You have also shown that while +j50 and -j50 may be the most accurate measurement points it is possible to still get excellent results with reactances much higher and lower than this with a VNA. Roger |
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nanoVNA Tweezer L/C Measurement Accuracy Examples
Greetings All,
As L/C component value measurement appears to be a present topic of interest here I decided throw my 2 cents in by posting a couple of tables that show the measurements results from tests I made with my nanoVNA tweezers. The tables illustrate the level of accuracy I obtained using tweezers with my nanoVNA running under "nanoVNA Saver" PC app control. As mentioned in an earlier post my nanoVNA tweezers were described in the Nov/Dec/2021 issue of QEX magazine. The attached tables along with some descriptive text can be download from the ARRL's QEX article support files site via the following link: The measurements were made over a frequency range of 50KHz to 150MHz (which is the practical upper limit for use of this method) for ranges of 1pF to 470pF, +/-1% (+/- 0.1pf and 0.25pF for the 1pF and 4.7pF values respectively) tolerance 0805 size SMD capacitors and 10nH to 4.7uH, +/-2%, 0805 inductors. They were installed in isolation on a low stray capacitance designed PC board. The reactance range for the capacitors tested was roughly 7 Ohms for 470pF at 50MHz to 1 megOhm for 1pF at 15MHz. The reactance range for the inductors tested was roughly 1 Ohm for 10nH@15MHz to 500 Ohms for 4.7uH@15MHz. The measured capacitor values obtained were all within the manufacture specified tolerances. The lower value inductors also measured within the manufactures +/-2% tolerance specification. However at the lower frequency range the larger value 1 and 4.7uH inductors were found to be about 3% from specified values at some frequencies. (As one would expect better measurement accuracy at lower frequencies I wonder if these larger inductors happen to be in fact slightly out of tolerance???) I find the tweezers to be a useful addition to my instrumentation inventory. For a case-in-point whilst experimenting with a class E, 14MHz 5W output power amplifier I needed to wind a pair of toroid inductors for the output network. The amplifier efficiency pivots on a proper output network. The optimum initial inductor values were calculated using a very useful class E amplifier design spreadsheet by WA0ITP that is based on specs from NM0S. The toroid inductors needed required less than 10 turns which means a single turn influenced the achievable inductance value by about 20%. After getting the L values as close as I could I entered the tweezer measured L values into the spreadsheet and re-calculated the optimum capacitor values. Out of the gate without any tuning I found the output power was just over 5 Watts with an efficiency of about 80%. There is no doubt that a proper test jig used with an expensive industrial quality VNA would provide a more stable and accurate measurement method for L/C components across a relatively wide frequency spectrum. However I also believe a set of tweezers can be a useful and easy to use nanoVNA accessory for those experimenters wishing to make L/C component measurements at frequencies below 150MHz with quite good accuracy. -- Tom, VA7TA Attachments: TweezerResultsCapacitors.jpg (54170) TweezerResultsInductors.jpg (68925) |
Rich NE1EE
Roger Need
Larry McElhiney
Eric KD7CAO
va3rr
Gregg Messenger VE6WGM
