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Re: Metalising plastic cases (Re: [nanovna-users] JNCRadio VNA 3G - Vector Network Analyzer - 50k to 3GHz)
Using your numbers Lou, I would not call a 20dB reduction in E-field "very poorly as a shield". The most difficult part of using any spray is getting it in to tight corners. I''ve done "touch up" on conductive spray painted parts with a small brush and the same paint sprayed on a piece of plastic as a "pallet". You do need to work fast though.
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Re: Nanovna-H4, looking for a case this will fit in.
Harbor Freight sells a small case like that as well...
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73, and thanks, Dave (NK7Z) ARRL Volunteer Examiner ARRL Technical Specialist, RFI ARRL Asst. Director, NW Division, Technical Resources On 1/16/22 05:53, Dale - 2W0ODS wrote:
I bought a MAX002S IP67 case from Amazon last night and it turned up this morning. |
Re: Nanovna-H4, looking for a case this will fit in.
The following is a copy of my post of 30th August 2021 which illustrates my solution to the enclosure/connector issues:
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The attached pictures show my solution to the SMA issue. 1) BNCs match all my other test gear removing the need for adapters when interfacing.Indeed BNCs are the standard connector used for professional test gear up to a few, GHz. (Perhaps 10GHz - Have to check that). 2) Any risk of straining the SMA attachment point to the PCB is eliminated. 3) The additional weight of the enclosure reduces the risk of the nanoVNA being dragged off the workbench by the attached cables. 4) The aluminium enclosure adds a measure of screening - probably a marginal. benefit. 5) The number of connection cycles permissible with BNCs while not infinite, is far, far greater than the the very small number of connection cycles specified for SMAs (in the hundreds if I remember correctly). The enclosure is made from extruded aluminium "U" section, readily available from eBay, with suitable apertures cut. I'm not sure that the reference planes for the BNC calibration pieces are perfect, but empirically, the results are the same as those obtained with the calibration devices supplied with the nanoVNA. Michael. (GW7BBY/GB2MOP). On 30/08/2021 04:25, Jim Lux wrote:
On 8/29/21 7:22 PM, scottad5u1@... wrote:My day job involves these connectors and others.? Many of my microwave connections use SMA.? I have discovered a few interesting things.This is totally the case.? Maybe you won't see it at 10MHz (but you might), but above 1 GHz, for sure. It's the "consistency" not the "mating force" |
Re: Metalising plastic cases (Re: [nanovna-users] JNCRadio VNA 3G - Vector Network Analyzer - 50k to 3GHz)
On Sat, Jan 15, 2022 at 11:51 PM, Roland Turner wrote:
I disagree with that blanket statement. The requirements and performance measurements are very different. There are a lot of variable, but for example, a surface that reflects 90% and transmits 10% of incident radiation might work very well as an antenna but very poorly as a shield. |
Re: Nanovna-H4, looking for a case this will fit in.
I bought a MAX002S IP67 case from Amazon last night and it turned up this morning.
It's absolutely perfect for my use and is waterproof too. Everything I need fits in, I've put the USB-C to USB-C cable in the back with the SMA-SMA leads and I have the calibration pieces in a little bag too. The foam is to cut out as it consists of little squares joined together, I've left one row to the left of the Nanovna as I will fit some SMA-M - SMA-F to save wear on the main SMA sockets and then I will remove a cube of foam by each SMA socket. |
NanoVNA Saver Markers Disappeared
Hello all...
I'm not sure this is the right place to ask this, but did not find any other. I downloaded the new version (0.3.10) and I no longer have the markers in the chart windows. Version 0.3.9 works fine. Any ideas what I did wrong? NanoVNA H4 Windows 10 64 bit Thank you. Ed |
Re: JNCRadio VNA 3G - Vector Network Analyzer - 50k to 3GHz
MIL-SPEC is applied to an item that meets or exceeds the Milatary specifications that is effect for that product being made.
The Company I worked for built products for the military. Power supplies for Amram, HV power suppies for several Headsup displays on Milatary Jets and Subs, as well as power converters and magnetics for most every Air plane manufacturer in the Free World. Retired Electronics Manufactureing Engineer of 35 years at OECO LLC, Milwaukie, Oregon Clyde Lambert KC7BJE |
Metalising plastic cases (Re: [nanovna-users] JNCRadio VNA 3G - Vector Network Analyzer - 50k to 3GHz)
On 15/1/22 23:47, 2sheds wrote:
I like the Al case, but as somebody mentioned, it likely doesn't justify doubling the price.The Sep/Oct 2016 issue of QEX contains an article on metalising the surfaces of 3D-printed plastic microwave horn antennas, the problem being working with curved shapes to improve performance over the more conventional (cheaper...) flat-surface designs that could be made with copper or brass sheet. The authors used MG Chemicals 843-340G Super Shield Silver Coated Copper Conductive Coating <> which can be obtained inexpensively from the usual electronics suppliers. The like-for-like results at 10 GHz (i.e. 3D-printing a test design using flat surfaces) were comparable to the use of foil or solid metal. If it's good enough to be an antenna conductor, it's almost certainly good enough for EMI shielding. Note that one of the problems that the authors had was gaps in the horn and its coupler enough to see light through, which naturally leaked microwave. A complete seal might be the harder problem. - Roland 9V1RT |
Re: JNCRadio VNA 3G - Vector Network Analyzer - 50k to 3GHz
On 1/15/22 4:43 PM, Jeff Green wrote:
Posted from a Wendy's in Bardstown (it sucks).copper foil tape is readily available, has a conductive adhesive, and works quite well. It's available in a variety of widths. Thin copper foil is also available - it's used by people making electric guitars and similar.? Some Scotch 77 or 74 spray adhesive and it's not coming off very easily. The shielding effectiveness is tricky to estimate. Most leakage is from wires that penetrate the shielding (so your USB cable). Second would be leakage through slits or gaps in the shielding - you need the perimeter of the hole to be << 1/2 wavelength, so at HF, that's pretty easy. At HF, the challenge is skin depth. The shielding needs to be > 5 skin depths. Skin depth in copper at 1 MHz is about 2.5 mils (0.0025 inches, 64 microns), so your shield would need to be 12 mils thick, which is a lot of 1 mil thick tape.? On the other hand, 0.032 aluminum (20 ga) is pretty good. is your friend. One also needs to worry about magnetic fields, for which lossy ferrite material in an elastomer are useful.
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Re: JNCRadio VNA 3G - Vector Network Analyzer - 50k to 3GHz
According to: the product is NOT available to the normal consumer, if I read the ad correctly.
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Mike C. On 1/15/2022 3:25 PM, Jeff Green wrote:
Posted on the road. |
Re: semi automatic quartz measuring
In my opinion there is no problem with sweeping 'couse I think about selecting crystals for filter (only) so initial frequency is known with high accuracy.
Dislord - is that possible to "ask" nanovna from PC (firnware with crystal measuring feature) for send crystal parameters to PC or is it impossible without modyfying firmware? mrn |
Re: JNCRadio VNA 3G - Vector Network Analyzer - 50k to 3GHz
Very interesting, but the nauseating company advert that the link goes to, (which would have irritated a 3yr old child), gave NO INFORMATION ON THE ACTUAL RF SUPPRESSION, EITHER MAGNITUDE OR FREQUENCY, regarding the rf suppression their products might provide.
Yours, irritated, Steve L, G7PSZ |
Re: JNCRadio VNA 3G - Vector Network Analyzer - 50k to 3GHz
Exactly¡. Just like ¡®military grade¡¯ translates to ¡®made by the lowest bidder¡¯. :)
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"Silence is golden. Duct tape is silver." On Jan 15, 2022, at 10:47, 2sheds <2sheds@...> wrote: |
Re: JNCRadio VNA 3G - Vector Network Analyzer - 50k to 3GHz
It's kinda like saying something is "Mil-SPEC". What does that mean?
I worked in a private company that did lot/most of its work for US Gov customers and you get used to those claims and others similar in nature. Since my final job before retiring was running a qualification review board of completed systems/subsystems for aerospace payloads i am especially sensitive when performing the final review to include extensive audits of parts, materials and processes to the point of on-site surveillance and complete parts audits. It is outrageously expensive but necessary when ultimately installed in something that will be beyond repair once in orbit. I don't need or want that in my nanovna and can usually do my own verification/validations to the extent required. I like the Al case, but as somebody mentioned, it likely doesn't justify doubling the price. When will affordable metal 3D printers be available? I guess there are work-arounds for EMI shielding that accomplish what we need. |
Re: JNCRadio VNA 3G - Vector Network Analyzer - 50k to 3GHz
"China does not play by the rules of the rest of the world. "
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And the USA does? Someone once stated that USA will newer be a dictatorship as there is no need, you are propagandised to such an extent that it would be counter productive. On Sat, 15 Jan 2022 at 00:26, W0LEV <davearea51a@...> wrote:
Yep. China does not play by the rules of the rest of the world. Their |
Re: JNCRadio VNA 3G - Vector Network Analyzer - 50k to 3GHz
My apologies, I missed the (now glaringly obvious) markings on the case.
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I was referring to more modest "Guaranteed quality: CE, FCC and RoHS compliance". claim, for whatever value such a claim has. - Roland 9V1RT ------------------------------------------------------------------------ On 15/1/22 02:49, W0LEV wrote:
They certainly do "claim" FCC and CE (the EU) approval by the presence of |
Re: JNCRadio VNA 3G - Vector Network Analyzer - 50k to 3GHz
William Smith
Any bets on how long it will take for someone to make a ¡°fake ¡°Chinese export mark where the letters are ¡°inadvertently¡° spaced out a little bit more than normal, so as to be indistinguishable from the European conformance mark?
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73, Willie N1JBJ
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Re: JNCRadio VNA 3G - Vector Network Analyzer - 50k to 3GHz
The real one has a larger space between the letters. []
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-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Mike C. Sent: Friday, January 14, 2022 6:18 PM To: [email protected] Subject: Re: [nanovna-users] JNCRadio VNA 3G - Vector Network Analyzer - 50k to 3GHz Gonna have to be more specific, "where's the beef?" Really impossible to see any difference. Other than the # marks, exactly the same. Mike C. On 1/14/2022 5:44 PM, Jeff Green wrote: Check out this: ;data=04%7C01%7Cvh2%40buffalo.edu%7Caed662ea9f3f480afa6108d9d7b435fb%7C96464a8af8ed40b199e25f6b50a20250%7C0%7C0%7C637777992429775194%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=wpfDK3QH7mnpq92MA1T%2By6x7VAi1BkCXctXPOMrWEyE%3D&reserved=0. The place I used to work got burned big time by "China Export" and "Conformit¨¦ Europ¨¦ene." |
Re: JNCRadio VNA 3G - Vector Network Analyzer - 50k to 3GHz
Yep. China does not play by the rules of the rest of the world. Their
people are generally good. But the government is crooked as .......well.......you fill in the missing word. Anything and everything to better the "state". Follow the leader blindly off a cliff and don't ask questions. Working regulatory on the EMC/RFI side, the last 25 to 30 years, I watched China, single handedly, convince the world markets it was all right to cheap at testing and approvals and that your exposure just did not justify the expense of doing things correctly and legally. They set the bar for blatant cheating with the 'more-or-less" proper marks (never "quite" correct) with absolutely no backing behind them. Now, even some major US companies weigh their exposure in the marketplace and follow China's example. Again, where the dickens is our FCC??!!!!! China these days fully realizes that CFR 47 (the FCC) is not worth the paper it's printed on. Dave - W?LEV On Fri, Jan 14, 2022 at 10:45 PM Jeff Green <Jeff.L.Green1970@...> wrote: Check out this:-- *Dave - W?LEV* *Just Let Darwin Work* |
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