Re: Surgical Tubing for SMA connectors
I used heat shrink, colors like my earlier VNA
Black for short
Green go 50 ohm
Clear for open.
Wanted purple for 75 but didn't find any yet.
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On Sat, Feb 27, 2021, 8:26 PM Pierre Martel <petem001@...> wrote: Great Idea!!! tl will help me a lot as I keep dropping those!
Le sam. 27 f¨¦vr. 2021 ¨¤ 16:12, Roger Bury <simplex-2@...> a ¨¦crit
:
I use 7/16 surgical tubing on my calibration SMA connectors. Makes them
easier to hold and find when i drop them.
73
Roger KC7OM
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Re: Surgical Tubing for SMA connectors
On 2/28/2021 5:54 PM, Will Fares wrote: Now, the one question I have with my meager nanovna experience is does a little connector saver alter the test point characteristics for our typical use. I would say that if you calibrated with the connector saver on you should be good to go. Just as long as the connector saver is of decent quality. Joe
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Re: Surgical Tubing for SMA connectors
I second Joe's (K1IKE) recommendation of using a "connector saver". I just realized I had a couple of them in my connector box so they will be installed immediately.
The major part of my career was in aerospace and particularly satellites and as a final reviewer of vendor proposals if I didn't see use of connector savers on box assembly and test I questioned the vendor's experience. Also, we must see that the nanovna as an experimental solution with limitations until we implement a better mousetrap that has better characteristics... within our budgets.
Now, the one question I have with my meager nanovna experience is does a little connector saver alter the test point characteristics for our typical use. I am looking at approximately 10.2 mm added to nanovna connector length. That's approx 3% added to wavelength at 3 GHz not accounting for line velocity, etc. I haven't contemplated working 3 GHz but given where we're going it may be that I do get my feet wet soon.
Thoughts? Ideas?
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Re: Surgical Tubing for SMA connectors
Joe,
At least on the three NanoVNA-H's and one NanoVNA-H4 I have, the standards do have rotating nuts. There was no easy way provided to prevent the centers from rotating, however. I cut a screwdriver slot in a couple of them to hold them, and carefully drilled and tapped another to attach an extending rod to hold on to. It would be nice if the originals had such holding rods, but I guess that would have increased the brass cost.
--John Gord
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On Sun, Feb 28, 2021 at 02:15 PM, Joe wrote:
On 2/28/2021 1:49 PM, Gyula Molnar wrote:
Because the fixing nut, which should rotate, cannot rotate, but forces the fixed to remain with the middle mandrel and move with it. The result is that
the center pin will sooner or later not connect with the correct torque
because it is worn out from a lot of rotation.
Hello Gyula and all,
This is true for standard SMA connectors, but the short/open/load tools
supplied with the NanoVNA do not have separate rotating collars on them.
The 3 devices are one solid piece each. The two 6 inch jumpers
supplied with the device do have collars that rotate.
I have used the Anritsu Sitemaster and Cellmaster for many years.
During certification training we were taught not to allow the
short/open/load devices to rotate while putting them on the set set.
The proper procedure is to hold the device so it cannot spin and only
turn the outer collar. The reason for this is, as you said, is to
minimize the wear on the center pin. The center male pin is only plated
and constant spinning of it can wear off the plating, causing a bad
connection. If you really are concerned, the solution might be to get a
couple of SMA Male/Female "connector savers". For the occasional user,
this probably will not be a problem.
I've had some of my calibration tools for over 30 years now and they are
still good because I'm careful to use them properly. BTW, Anritsu used N
connectors on their calibration tools.
Quality SMA connectors are good for around 500 connection cycles. BUT
this is if you install and remove them properly, AND if they are quality
connectors. We really don't know the lineage of the ones supplied with
the NanoVNA. Finger tight, like you stated, is fine. Just because you
can put a wrench on them doesn't mean they have to be white knuckle tight.
73, Joe, K1ike
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Re: Surgical Tubing for SMA connectors
That depends on where you got them. The ones supplied with
Hugens H4 rotate and the ones I got with a clone before that one
also rotate.
This is true for standard SMA connectors, but the short/open/load tools
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supplied with the NanoVNA do not have separate rotating collars on them.
The 3 devices are one solid piece each. The two 6 inch jumpers
supplied with the device do have collars that rotate.
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Re: Surgical Tubing for SMA connectors
On 2/28/2021 1:49 PM, Gyula Molnar wrote: Because the fixing nut, which should rotate, cannot rotate, but forces the fixed to remain with the middle mandrel and move with it. The result is that the center pin will sooner or later not connect with the correct torque because it is worn out from a lot of rotation. Hello Gyula and all, This is true for standard SMA connectors, but the short/open/load tools supplied with the NanoVNA do not have separate rotating collars on them. The 3 devices are one solid piece each. The two 6 inch jumpers supplied with the device do have collars that rotate. I have used the Anritsu Sitemaster and Cellmaster for many years. During certification training we were taught not to allow the short/open/load devices to rotate while putting them on the set set. The proper procedure is to hold the device so it cannot spin and only turn the outer collar. The reason for this is, as you said, is to minimize the wear on the center pin. The center male pin is only plated and constant spinning of it can wear off the plating, causing a bad connection. If you really are concerned, the solution might be to get a couple of SMA Male/Female "connector savers". For the occasional user, this probably will not be a problem. I've had some of my calibration tools for over 30 years now and they are still good because I'm careful to use them properly. BTW, Anritsu used N connectors on their calibration tools. Quality SMA connectors are good for around 500 connection cycles. BUT this is if you install and remove them properly, AND if they are quality connectors. We really don't know the lineage of the ones supplied with the NanoVNA. Finger tight, like you stated, is fine. Just because you can put a wrench on them doesn't mean they have to be white knuckle tight. 73, Joe, K1ike
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Re: Surgical Tubing for SMA connectors
These are nice cases for the nanovna and tinysa! Get Outlook for Android<> ________________________________ From: [email protected] < [email protected]> on behalf of Jim Shorney <jshorney@...> Sent: Sunday, February 28, 2021 12:09:43 PM To: [email protected] < [email protected]> Subject: Re: [nanovna-users] Surgical Tubing for SMA connectors Interesting what you can find if you look around. Where I work I often get surplus zippered gig bags from microphones and other small items. These work nicely for small portable devices. The one I use for my Tascam DR-05 has room for several SD cards and a spare set of batteries. Also the much discussed boxes from Harbor Freight in the USA come in various sizes and shapes for not a lot of money. 73 -Jim NU0C On Sun, 28 Feb 2021 08:43:16 -0800 af4ze@... wrote: I have started making "kits" for my various tools - I have used zippered cases ( pencil cases originally from the school supply section), heavy duty Zip lock and occasionally ESD bags (grocery store for zip locks, ESDs "recycled" from past shipments), and the little latch-able food storage bins (rectangular, many sizes, next to the Zip lock bags at my supermarket). I've also started using Plano storage bins (often in the fishing tackle section of Walmart, BassPro, etc...).
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Re: Surgical Tubing for SMA connectors
Hi Roger,
It is unfortunate to blend silicone tube and SMA in this way.
Because the fixing nut, which should rotate, cannot rotate, but forces the fixed to remain with the middle mandrel and move with it. The result is that the center pin will sooner or later not connect with the correct torque because it is worn out from a lot of rotation. It is no coincidence that a torque wrench is used to tighten these types of connectors. But for us, it is enough to secure it by hand if it is firmly attached.
The correct solution is when the middle mandrel no longer rotates at the beginning of the thread and the sleeve and mandrel do not wear each other but only slide into it. In short, such an implementation of the idea is unfortunate. If you just want to increase the size of the nut, you have to cut it around there to be able to rotate separately.
73, Gyula HA3HZ
--
*** If you are not part of the solution, then you are the problem. ( ) ***
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On Sun, Feb 28, 2021 at 09:06 AM, Max Donoghue wrote:
The PC software is NanoVNASaver version 0.3.9
Max
Did you set the number of points to 101 under the sweep settings on the nanoVNA? Version 3.9 is known to have some bugs. Try 3.8 Roger
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Then let's run to him again. See the latest version of NanoVNA-Saver 0.3.8. screenshot.
There is a program running on your computer that you think is displaying incorrect data.
There may be setup issues, but the program has not been identified so far.
--
*** If you are not part of the solution, then you are the problem. ( ) ***
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Re: Surgical Tubing for SMA connectors
Interesting what you can find if you look around. Where I work I often get surplus zippered gig bags from microphones and other small items. These work nicely for small portable devices. The one I use for my Tascam DR-05 has room for several SD cards and a spare set of batteries. Also the much discussed boxes from Harbor Freight in the USA come in various sizes and shapes for not a lot of money. 73 -Jim NU0C On Sun, 28 Feb 2021 08:43:16 -0800 af4ze@... wrote: I have started making "kits" for my various tools - I have used zippered cases ( pencil cases originally from the school supply section), heavy duty Zip lock and occasionally ESD bags (grocery store for zip locks, ESDs "recycled" from past shipments), and the little latch-able food storage bins (rectangular, many sizes, next to the Zip lock bags at my supermarket). I've also started using Plano storage bins (often in the fishing tackle section of Walmart, BassPro, etc...).
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The PC software is NanoVNASaver version 0.3.9
Max
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Re: Surgical Tubing for SMA connectors
This is a great idea! Three thoughts to contribute:
1) Be careful about installing the tubing in a way that makes you "spin" the SMA connector instead of the SMA nut - to preserve the center pin contact surfaces, try not to rotate or spin the connector and center pin, only twist the nut.
2) I have started using short sections of colored shrink wrap to "tag" the various bit in a kit. Doesn't help the fingers, but easier on the eyes...
3) You didn't mention it, but in your photo it looks like you have a box for all your VNA bits - this is an excellent practice! I have started making "kits" for my various tools - I have used zippered cases ( pencil cases originally from the school supply section), heavy duty Zip lock and occasionally ESD bags (grocery store for zip locks, ESDs "recycled" from past shipments), and the little latch-able food storage bins (rectangular, many sizes, next to the Zip lock bags at my supermarket). I've also started using Plano storage bins (often in the fishing tackle section of Walmart, BassPro, etc...). Then I keep all the bits with the instrument to make a standard measurement. High quality RF components are still expensive, but the inexpensive imports are good enough for standard measurements, and it is sure nice to have everything in a box "ready to go"...
73
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And why not? Cut the ends off and you have a nice 4-wire interconnect cable for projects. 73 -Jim NU0C On Sun, 28 Feb 2021 11:10:18 -0500 "Ken Sejkora" <kjsejkora@...> wrote: Guilty, as charged ? -- Ken, WB?OCV
From: Joe
Sent: Sunday, February 28, 2021 10:58 AM
To: [email protected]
Subject: Re: [nanovna-users] Bad Cable
Ah, but there is the frugal parsimonious ham that will see it and take
it home. We, oops I mean they can't help themselves......
Joe
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Re: Surgical Tubing for SMA connectors
How about the little yellow caps? They should be easy to spot but one of mine has gone feral.
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Guilty, as charged ? -- Ken, WB?OCV From: Joe Sent: Sunday, February 28, 2021 10:58 AM To: [email protected]Subject: Re: [nanovna-users] Bad Cable Ah, but there is the frugal parsimonious ham that will see it and take it home. We, oops I mean they can't help themselves...... Joe
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Ah, but there is the frugal parsimonious ham that will see it and take it home. We, oops I mean they can't help themselves......
Joe
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On 2/28/2021 9:22 AM, Gene Rozea wrote: We???d just toss them ???
From: Donald S Brant Jr<mailto:dsbrantjr@...>
Sent: Sunday, February 28, 2021 8:58 AM
To: [email protected]<mailto:[email protected]>
Subject: Re: [nanovna-users] Bad Cable
In the lab, whenever I find a defective cable I cut off the end so that someone doesn't pull what looks like a perfectly good cable out and try to use it.
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Re: Does V2.4 have full two port
That was the "yep" bit as in your assumption was correct.
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On Sun, 28 Feb 2021 at 16:07, David Geng <d.geng@...> wrote: Thanks for your reply and interested to see the 6G version coming.
However, I think my current concern is about the 4G, iirc, v2.4, does it
have one directional ports or support full two ports, i.e. s11, s12, s21,
s22 in one go.
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Re: Does V2.4 have full two port
V2.4 (V2 plus4) is still two port one path, but overall architecture is redesigned and port 2 return loss is much improved (typically >20dB) so you can get good results reversing the DUT and using two port one path calibration:
ttps://scikit-rf.readthedocs.io/en/latest/api/calibration/generated/skrf.calibration.calibration.TwoPortOnePath.html
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Re: Does V2.4 have full two port
Thanks for your reply and interested to see the 6G version coming. However, I think my current concern is about the 4G, iirc, v2.4, does it have one directional ports or support full two ports, i.e. s11, s12, s21, s22 in one go.
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2sheds
Gyula Molnar
Roger Need
Jim Shorney
Bear Albrecht
OwO