Hi Andy On Wed, Nov 20, 2019 at 06:37 PM, Andy wrote: OK I started testing the charging current on my NVNA.
Typically 650ma on an empty 400ma supplied cell, oh dear !!! That's 1.625C. Exceeds spec of 1C max. Bad mojo. Please try charging from a USB2 standard port and measure the current. I wasn't expecting that to be honest, I really did assume that there would be
some controller regulating the current. Something is limiting the current given that you were using a 2.1A mains adapter. My guess it is the battery protection module in the battery itself. Search for DW01-P One Cell Lithium-ion/Polymer Battery Protection IC. I consider that the IP5303 datasheet to be a bit misleading in my opinion. It is certainly hard to understand what the charge current will be in practice. Before I did the test, I also measure the current on a supposedly charged
cell, and it wasn't actually any different. My guess is that the battery voltage never reached 4.1V so the IP5303 just kept going.. Guess I'll be modding mine for an 18650 cell shortly. Not convinced this is the best option now. An 18650 would require an external battery protection module. I've been doing some tests using an old cell phone battery. It is a NEC MAS-BD0021-A001 1100mAh Li-Ion. Must be at least 15 years old. From a full charge it will run the nvna for 4 hours before the over discharge protection kicks in. A full charge using a 1A mains adapter takes 3 hours and the charge current never exceeds 400mA i.e. 0.37C. On a USB2 standard port the charge current never exceeds 200mA i.e. 0.18C. Cannot find a spec for this particular battery but that looks good to me. Note that supplied SD 602040 is a Li-Po; the NEC is a Li-Ion battery. The different discharge characteristics may need mods to the discharge table in the firmware. I haven't looked at that yet. 73 Nick
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Re: [nanovna-f] Why are Archives visible to subscribers only?
I tend to be annoyed Content is available by web searches including site:groups.io/g/nanovna-users developers can get back to work That work includes compiling requirements, including input from subscribers
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FYI, bought one of the 'deal's ($21), from ebay. Got a tracking number and was told it had been shipped. Never arrived so i contacted the seller and got no reply. Ebay got involved when i contacted the seller, gave them 5 days to make good and when they did not, ebay gave me a full refund!EBay makes your purchase no risk, so go ahead and take a chance. Sometimes you get a good one.Ron
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-------- Original message --------From: "David Feldman via Groups.Io" <wb0gaz@...> Date: 11/23/19 5:27 AM (GMT-07:00) To: [email protected] Subject: Re: [nanovna-users] Deal on ebay As this ("deal on ebay") has been a recurring theme for some time (these sorts of offers happen on other items, nanovna is one of the subject items for this sort of spam/scam), I would like to suggest the following:The majority of these non-delivery "deals" arise from misuse of an existing ebay account. If you purchase from one of these listings, you can (and very much should) seek a refund from ebay after the delivery time passes with no delivery. Almost all of these listings share common characteristics - abnormal buy-it-now pricing (<USD 25), few seller feedbacks (<100, sometimes very few with private or hidden details), no other related items listed (i.e., other items that don't seem to be rf electronics), and no evidence of feedback for sale/delivery of the nanovna. Be sure you're looking at a listing for the nanovna proper (there are numerous multi-item listings that show a price range and might initially look faulty but are not necessarily so.)Any ebay user can click "report item" link (navigation for US version users is this, other languages may vary --- right side, part way down the screen to the right of "shipping and payments", you may need to scroll down to find it, as it's a simple text link and not very easy to see). Click on "report item" (then you may need to re-supply your ebay password), then choose report category = "listing practices", then choose from reason for report = "fraudulent listing activities", then choose from detailed description = "you suspect that a listing is fraudulent". Finally, click submit report. ebay usually will remove these listings sooner than might otherwise be the case. Doing this properly may help reduce the preponderance of these dead-end listings.Thank you for your interest in and support of nanovna-users,Dave
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I would suggest that with the NanoVNA being already such a low price, there is a cost to one's time and effort to engage questionable vendors or potentially faulty or misrepresented products. While I think that there is definitely a benefit to the low price, the interest it seems to be based largely on the price appears with relatively little concern as to the quality or performance. I think ultimately many hams that are new to the idea of the VNA will dismiss it as uninteresting junk if it is perceived as simply being cheaper. On Sat, Nov 23, 2019 at 10:41 AM Gary Rogerson via Groups.Io <gary.rogerson= [email protected]> wrote: Hope it¡¯s not old news, but I just ordered one at Walmart.com for ~$38.
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Re: [nanovna-f] Why are Archives visible to subscribers only?
My opinion aligns more with David. The basic question is if this is a product support group or a private group for developers or otherwise includes proprietary information. If this forum is only for developers or is likely to include proprietary info, then it makes sense that the archives are private. But if the purpose of the forum is to provide product support to users, then it makes more sense that the archives are open. Last I heard the NanoVNA was an Open Source project so there should be no proprietary info?
Personally, I tend to be annoyed when I have to join a group in order to research the answer to a simple problem, or even a complex one. When I have joined a group, I get even more annoyed when I see half the postings are asking for answers to the same problems that were answered multiple times in recent weeks. If the message archives are open and searchable, at least some of the questions will be answered before they ask the group AGAIN.
I consider the best reason for an open support group is that eventually there will be enough expert users that newbie questions can be answered by them and the developers can get back to work on the next version or product upgrade. But this is just my opinion.
73, Doug Reed, N0NAS.
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Hope it¡¯s not old news, but I just ordered one at Walmart.com for ~$38.
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go to walmart .com you get it there for a couple bucks more 3 day delivery and ou know you haven't been scammed. But also, read the fine print because you only get bare bones, no cables, no calibration standard and no shielding. All things that would not deter me because I have them and can shield the unit easy but are not preferable by most people.
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Dave, excellent information. I have 3000+ purchases on eBay. Lots of items from China. I always do as you suggest, check the Seller's Feedback and number of sales.
Just one last thought...¡ Recently, I purchased an 'F' model from a store in China. It was the 'usual' price, around $140. Excellent Feedback (99.3%) on 20,000+ sales. MY problem was: I ordered it on the last day of September. I was told by the Seller that the entire country goes on 'holiday' the first week of October, including all shipping, etc.
Sure enough, weeks went by with no updates on the Tracking Number. I contacted the Seller and he told me he couldn't track it either.
I was given a refund very quickly and ordered another 'F' from another Seller, for the same price. It showed up within the expected time.
ron
N4UE
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For those that want to experiment with a nice tool to add/remove transmission/coax line impact there is this very advance excel tool It requires excel from Office 97 or newer and macro's enabled. It includes a large database of transmission/coax models and (like simSmith) can read all the VNA output files. This tool could be some inspiration for nanoVNA-Saver :-) -- NanoVNA Wiki: /g/nanovna-users/wiki/homeNanoVNA Files: /g/nanovna-users/filesErik, PD0EK
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Coax cable length influence on calibration
Hi all,
today I performed a NanoVNA calibration test to find out if the coax cable length and quality has any negative influence specially on the S11 return loss.
The calibration setup is 10kHz-900MHz at 808 points.
For the test I used high quality coax cable (M17/152) and standard coax cable (RG174U).
The reference test was done directly on the NanoVNA port connectors. For the thru test a 5 cm long semi rigid coax cable was used (picture 1).
Next, a 20 cm long M17/152 coax cable was tested (picture 2).
Then, a 93 cm long M17/152 coax cable was tested (picture 3).
And last, a 70 cm long RG174U coax cable was tested (picture 4).
Picture 5 shows the test result for the RG174U coax cable for S21.
All test conditions have been repeated. The differences between the two tests were negligibly.
One can see, that the coax cable length has some negative impact on S11, specially with the 20 cm long coax cable.
The quality of the coax cable plays obviously a minor roll.
Do the experts among us have an explanation why this is as such?
Best regards
Norbert, DG1KPN
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Simulated port extension methods,:
1. 1 - 500Mhz sweep shorted RG-58C/U (Belden 8262)
2. subtract ideal coaxial line
3. subtract datasheet loss data coaxial line
4. subtract datasheet loss data coaxial line (zoom)
5. subtract advanced model RG-58C/U (Belden 8262) coaxial line (zoom)
Of course, this is simulation only. But you can try load real measurements (s1p) format.
I not a Nanovna or external program developer.
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As this ("deal on ebay") has been a recurring theme for some time (these sorts of offers happen on other items, nanovna is one of the subject items for this sort of spam/scam), I would like to suggest the following:
The majority of these non-delivery "deals" arise from misuse of an existing ebay account. If you purchase from one of these listings, you can (and very much should) seek a refund from ebay after the delivery time passes with no delivery.
Almost all of these listings share common characteristics - abnormal buy-it-now pricing (<USD 25), few seller feedbacks (<100, sometimes very few with private or hidden details), no other related items listed (i.e., other items that don't seem to be rf electronics), and no evidence of feedback for sale/delivery of the nanovna. Be sure you're looking at a listing for the nanovna proper (there are numerous multi-item listings that show a price range and might initially look faulty but are not necessarily so.)
Any ebay user can click "report item" link (navigation for US version users is this, other languages may vary --- right side, part way down the screen to the right of "shipping and payments", you may need to scroll down to find it, as it's a simple text link and not very easy to see). Click on "report item" (then you may need to re-supply your ebay password), then choose report category = "listing practices", then choose from reason for report = "fraudulent listing activities", then choose from detailed description = "you suspect that a listing is fraudulent". Finally, click submit report. ebay usually will remove these listings sooner than might otherwise be the case. Doing this properly may help reduce the preponderance of these dead-end listings.
Thank you for your interest in and support of nanovna-users,
Dave
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A firmware upgrade for the NanoVNA was just announced by edy555:
"Just released ,NanoVNA firmware 0.5.1 , add marker function 'group delay to electrical delay"
Hard to translate the Japanese description, but I believe it allows the electrical delay values to be changed by dragging the marker - in addition to using the onscreen keyboard.
- Herb
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Of course. Port extension not ideal. Simplest method only compensated the electrical lenght. More advenced method use simple frequency depend loss model. Best the complex model.
With nanovna + zplots possibly caracterize unkown coax parameters.
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Re: [nanovna-f] Why are Archives visible to subscribers only?
Hi David,
Maybe because members of the group have disclosed the information to the group - if you are interested, you have to log in. This is the case elsewhere.
The -F group is another group, if you have a problem with them, ask for another group.
Regards, Gyula HA3HZ
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Hi Sam,
Take care with port extension. At low freq you can get away with it without much error. However, as you go to higher freq, it can really mess things up.
Better off knowing what the fixture parasitic looks like and use proper de embedding arithmetic to "move the measure" plane.
Alan
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Has anyone considered using TNC connectors? Not as heavy as N Types and, according to Amphenol, good from DC to 10 Gig.
Paul
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On Wed, Nov 20, 2019 at 10:11 AM, Larry Rothman wrote: Please DO NOT USE any LiIon battery that is beginning to swell !!!? Recycle it.Once a LiIon battery is starting to swell, its internal chemistry is unstable. Larry, While I appreciate your abundance of caution, I have observed that these flat batteries "just begin" to swell almost immediately (i.e., a fraction of a mm and they will spin on the desk) after only a few cycles, and they continue to slowly expand throughout their useful lives (2-3 years), until they will no longer fit in the phone and the back cover cannot be snapped in place -- and none of them have ever gone exothermic. At that point I discard them in my 55-gallon burn barrel with the trash, and burn them up, without noticeable incident. I think it's likely that the rare ones that do go exothermic have faulty protection circuits, or careless re-purposing; hence my question about the 2 additional terminals. Thanks for the Instructables article; it's good to know the contacts can be soldered without ruining the battery. 73, --kv5r
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I agree with David. I bought a Nano VNA which is very good for the money but my eyes are not good enough for it to be of any use as a portable instrument so I immediately ordered a NanoVNA-F purely for the larger screen. The NanoVNA is now primarily used with the PC. 73 Conrad PA5Y ________________________________ From: [email protected] < [email protected]> on behalf of Dr. David Kirkby, Kirkby Microwave Ltd via Groups.Io <drkirkby@...> Sent: 22 November 2019 17:30 To: [email protected] < [email protected]> Subject: Re: [nanovna-users] F303 and 4" LCD for next generation NanoVNA #circuit #flash_size #improvement #enclosure #battery On Fri, 22 Nov 2019 at 15:32, David J Taylor via Groups.Io <gm8arv= [email protected]> wrote:
For me, having the extra resolution of the 4.3-inch display would be a
significant benefit, and the extra size would not be unwelcome. More than
101 points per plot would be possible. The increased weight would be more
than offset by increased usage time. We already see some of these
advantages in the NanoVNA-F.
73,
David GM8ARV
I agree with David - weight is not an issue. I think if Hugen wants to sell these in a reasonable quantity, I think the screen will need to be at least as big as the NanoVNA-F, as I think many people will buy the NanoVNA-F for a better screen. Dave. -- Dr. David Kirkby, Kirkby Microwave Ltd, drkirkby@... Telephone 01621-680100./ +44 1621 680100 Registered in England & Wales, company number 08914892. Registered office: Stokes Hall Lodge, Burnham Rd, Althorne, Chelmsford, Essex, CM3 6DT, United Kingdom
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On Fri, 22 Nov 2019 at 15:32, David J Taylor via Groups.Io <gm8arv= [email protected]> wrote:
For me, having the extra resolution of the 4.3-inch display would be a
significant benefit, and the extra size would not be unwelcome. More than
101 points per plot would be possible. The increased weight would be more
than offset by increased usage time. We already see some of these
advantages in the NanoVNA-F.
73,
David GM8ARV
I agree with David - weight is not an issue. I think if Hugen wants to sell these in a reasonable quantity, I think the screen will need to be at least as big as the NanoVNA-F, as I think many people will buy the NanoVNA-F for a better screen. Dave. -- Dr. David Kirkby, Kirkby Microwave Ltd, drkirkby@... Telephone 01621-680100./ +44 1621 680100 Registered in England & Wales, company number 08914892. Registered office: Stokes Hall Lodge, Burnham Rd, Althorne, Chelmsford, Essex, CM3 6DT, United Kingdom
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Oristo
Gyula Molnar
Dr. David Kirkby, Kirkby Microwave Ltd