I can pull mine apart and see if I can come up with something. I agree, the "external" parts need dome protection
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On 7/11/2019 11:39 AM, alan victor wrote: There is some value added packaging if it can be done at a reasonable cost. The slide switch and the rotary wheel switch are subject to failure or breakage. Especially when used in the field. The LCD display in the field is nearly impossible to read unless you shield it from the sun. I used it to measure an antenna outdoors and had to either put it in a black box or wait till I had some cloud cover. Some sort or reasonable shroud for protection and enhanced viewing for field use would be great. The USB port seems ok. A port for firmware updates would be nice. Comments? Alan
________________________________
From: [email protected] <[email protected]> on behalf of Larry Rothman <ac293@...>
Sent: Thursday, July 11, 2019 2:50 PM
To: [email protected]
Subject: Re: [nanovna-users] Extended back cover
Folks,
Instead of reinventing the wheel to design a case, have a look at the 1553BBK series Hammond housing.
It's approx $12 CAD.
It looks like a small amount of internal trimming might be needed but it looks perfect.
Regards,
Larry
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Some people don't have the "ability" to modify that box. This way, if you just wanted to add a (or bigger) battery, it is only 4 screws and double sided tape (which I could probably throw in).
Shipping is the other variable, but it could be put in a padded envelope and mailed (I will have to look into the hazardous material rules)
Frank
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On 7/11/2019 10:50 AM, Larry Rothman wrote: Folks,
Instead of reinventing the wheel to design a case, have a look at the 1553BBK series Hammond housing.
It's approx $12 CAD.
It looks like a small amount of internal trimming might be needed but it looks perfect.
Regards,
Larry
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There is some value added packaging if it can be done at a reasonable cost. The slide switch and the rotary wheel switch are subject to failure or breakage. Especially when used in the field. The LCD display in the field is nearly impossible to read unless you shield it from the sun. I used it to measure an antenna outdoors and had to either put it in a black box or wait till I had some cloud cover. Some sort or reasonable shroud for protection and enhanced viewing for field use would be great. The USB port seems ok. A port for firmware updates would be nice. Comments? Alan ________________________________ From: [email protected] < [email protected]> on behalf of Larry Rothman <ac293@...> Sent: Thursday, July 11, 2019 2:50 PM To: [email protected]Subject: Re: [nanovna-users] Extended back cover Folks, Instead of reinventing the wheel to design a case, have a look at the 1553BBK series Hammond housing. It's approx $12 CAD. It looks like a small amount of internal trimming might be needed but it looks perfect. Regards, Larry
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I think it depends on the battery. I'm looking for "surplus" batteries to keep the cost down. I had mine open, and never looked to see the mAh rating on the battery. I figure under 1000mAh should be good
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On 7/11/2019 10:27 AM, Eric Haskell [KC4YOE] wrote: I am still interested, depending on price.
Norman Eric Haskell, KC4YOE
3709 Oakbriar Lane
Colleyville, TX 76034 USA
________________________________
From: [email protected] <[email protected]> on behalf of Frank S <ka2fwc@...>
Sent: Thursday, July 11, 2019 7:25 AM
To: [email protected]
Subject: Re: [nanovna-users] Extended back cover
If anyone is interested, I'll find a battery and make up a package with
screws and figure out a price. I can make the backs in black or white
(or other colors)
Frank
On 7/11/2019 5:44 AM, Nuno wrote:
Nice job!
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Folks,
Instead of reinventing the wheel to design a case, have a look at the 1553BBK series Hammond housing.
It's approx $12 CAD.
It looks like a small amount of internal trimming might be needed but it looks perfect.
Regards,
Larry
|
I am still interested, depending on price. Norman Eric Haskell, KC4YOE 3709 Oakbriar Lane Colleyville, TX 76034 USA ________________________________ From: [email protected] < [email protected]> on behalf of Frank S <ka2fwc@...> Sent: Thursday, July 11, 2019 7:25 AM To: [email protected]Subject: Re: [nanovna-users] Extended back cover If anyone is interested, I'll find a battery and make up a package with screws and figure out a price. I can make the backs in black or white (or other colors) Frank On 7/11/2019 5:44 AM, Nuno wrote: Nice job!
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If anyone is interested, I'll find a battery and make up a package with screws and figure out a price. I can make the backs in black or white (or other colors)
Frank
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On 7/11/2019 5:44 AM, Nuno wrote: Nice job!
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Re: Narrow band filters and LO phase noise/jitter?
In this video, Alan also correctly designates the IF BW as Resolution BW in his notes.
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On Thu, Jul 11, 2019 at 07:28 AM, <hellhound604@...> wrote:
Another video nice video explaining RBW is this one
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Re: Narrow band filters and LO phase noise/jitter?
and is it the same as IF BW ? Nope. Traditional analyzers with non-baseband IF scan wider bands
mixed down to some intermediate frequency,
so IF BW must be wide enough to pass all signals to be subsequently resolved.
Spectrum (and Network) analyzers have multiple up/down conversions in their RF chain before reaching the last IF section. The IF BW of those middle converters (before the last IF) is fairly wide however the BW of in the last IF section before the detector is indeed the same as Resolution BW There are multiple LC or crystal filters which determine the IF BW which is in fact the RBW at this stage (such as 1MHz, 100KHz, 30KHz, 1KHz and so on) so if we define the IF BW of the whole RF section as the narrowest BW which always occurs in the last IF of any receiver then yes IF BW is the same as RBW in spectrum or network analyzers. in older SA, in order to implement very narrow RBW such as 1Hz or 10Hz, they would actually do another down conversion in the last IF section would do the filtering at several KHz and then up convert it back again to the IF frequency. in modern SA they implement these very narrow RBW in DSP after detector and sampling by using digital filtering. As such, they can achieve much faster frequency scans at very narrow RBW
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Re: Narrow band filters and LO phase noise/jitter?
Another video nice video explaining RBW is this one
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Re: Narrow band filters and LO phase noise/jitter?
What does RBW stand for Resolution bandwidth. This video [1:50/5:14] uses an example of a 300 Hz RBW to resolved equal amplitude signals separated by 1 kHz: and is it the same as IF BW ? Nope. Traditional analyzers with non-baseband IF scan wider bands mixed down to some intermediate frequency, so IF BW must be wide enough to pass all signals to be subsequently resolved.
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Re: Narrow band filters and LO phase noise/jitter?
The IF BW is " intermediate frequency bandwidth" What does RBW stand for and is it the same as IF BW ?
Thanks in advance
Greg
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-----Original Message----- From: [email protected] < [email protected]> On Behalf Of alan victor via Groups.Io Sent: 10 July 2019 19:42 To: [email protected]Subject: Re: [nanovna-users] Narrow band filters and LO phase noise/jitter? Excellent point. Is there a tag between the analyzer sweep range and its resolution BW? I should do a cal over a reasonable narrow frequency range and see if this helps the situation. Otherwise it may very well be RBW limited. ________________________________ From: [email protected] < [email protected]> on behalf of amirb <amir.borji@...> Sent: Wednesday, July 10, 2019 4:15 PM To: [email protected]Subject: Re: [nanovna-users] Narrow band filters and LO phase noise/jitter? it's not that surprising, I think, considering that the RBW (or IF BW) of this instrument is definitely not narrow enough to give you the resolution required for like a 1KHz or perhaps even 5KHz span. of course number of sample points is another bottleneck but not as critical as the RBW. Does anybody know what the RBW actually is?
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Re: Narrow band filters and LO phase noise/jitter?
My last message was meant in response to Oristo. Forgot to quote it.
"Use of 74LVC4066 Quad bilateral switch instead of SA612 mixer is elegant;
given square wave Si5351 output, its ideal mixer becomes a switch...
That would be a nice upgrade for nanoVNA2 (picoVNA?)"
It might also be better to redesign the resistance bridge for wider impedance measurement.
Current balanced 50 ohm bridge, NanoVNA design, does not have wide range. The FA-VA5 and EU-1KY antenna analyzers
have different front end designs. The FA-VA5 has a reasonable measurement range of 5 to 1000 ohms, far better than NanoVNA.
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Re: Narrow band filters and LO phase noise/jitter?
It might also be better to redesign the resistance bridge for wider impedance measurement.
Current balanced 50 ohm bridge, NanoVNA design, does not have wide range. The FA-VA5 and EU-1KY antenna analyzers
have different front end designs. The FA-VA5 has a reasonable measurement range of 5 to 1000 ohms, far better than NanoVNA.
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Re: Narrow band filters and LO phase noise/jitter?
I would think that just putting resistors in series with each side of the crystal would raise the impedance enough to unload the Q. I would start with 1 K ohm on each side (for the series measurement), and see if it narrows the response. Of course this comes at the expense of increasing the attenuation of the DUT.
Stuart K6YAZ
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-----Original Message----- From: alan victor <avictor73@...> To: nanovna-users < [email protected]> Sent: Wed, Jul 10, 2019 5:02 pm Subject: Re: [nanovna-users] Narrow band filters and LO phase noise/jitter? A thought experiment and an issue with comparison of the single crystal with the matched filter counterpart. A single crystal in series mode is embedded in a 50 ohm system, in this measurement. Essentially, operating with a doubly loaded Q. If this de-Q effect is significant, the issue we are trying to address may not show itself. We really would like to transform the VNA source and load in affect to an impedance level that would operate the xtal as close as possible to its unloaded Q value. Of course, NOT a straight forward task.
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Re: Narrow band filters and LO phase noise/jitter?
Yes, because of the strong impedance mismatch between the crystal and the VNA there may be some passband ripple.
But it is still instructive to see what the passband curve looks like with closely scanned/calibrated NanoVNA.
I'll leave the impedance matching problem to you. Maybe APLAC simulation will help.
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Re: Narrow band filters and LO phase noise/jitter?
A thought experiment and an issue with comparison of the single crystal with the matched filter counterpart. A single crystal in series mode is embedded in a 50 ohm system, in this measurement. Essentially, operating with a doubly loaded Q. If this de-Q effect is significant, the issue we are trying to address may not show itself. We really would like to transform the VNA source and load in affect to an impedance level that would operate the xtal as close as possible to its unloaded Q value. Of course, NOT a straight forward task.
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Re: Narrow band filters and LO phase noise/jitter?
Thanks, George, for the FA-VA5 video hyperlink:
Use of 74LVC4066 Quad bilateral switch instead of SA612 mixer is elegant;
given square wave Si5351 output, its ideal mixer becomes a switch...
That would be a nice upgrade for nanoVNA2 (picoVNA?)
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Re: Narrow band filters and LO phase noise/jitter?
Here is some information on phase noise on the chip, Si5351A used in the VNA.
It is reasonable, nothing extraordinary, however, the loop configured in the VNA may do some noise correction. In any case, I'll look at a crystal. If that plays out and the required resolution is quite small, it may imply that the span I must use is much less than what I currently selected.
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Eric Haskell [KC4YOE]
Oristo
Nuno