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Re: NanoVNA firmvare, compiled by DiSlord #firmware with MiniSD support #firmware

 

My test SD cards foto


Re: NanoVNA firmvare, compiled by DiSlord #firmware with MiniSD support #firmware

 

In my test i use
Samsung EVO Plus 128Gb HD XL
Samsung EVO Plus 32Gb SD HC
Kingston MicroSD HC1 16Gb

All worked, detected
128Gb flash not write (used exFat filesystem, not supported), but card answer and read sectors ok

All others card answer and work
My card powerup log on 1 screenshot
SD_SendCmd err CMD0, 0xFF, 0x00000000
CMD0 Ok
CMD8 Ok
CMD8 0xAA010000
CMD8 Ok, run ACMD41
ACMD41 99
ACMD41 0x0080FFC0
CardType 4
My card powerup log on 2 screenshot
CMD0 Ok
CMD8 Ok
CMD8 0xAA010000
CMD8 Ok, run ACMD41
ACMD41 99
ACMD41 0x0080FFC0
CardType 4
Try made several screenshots, possible card can`t powerup from first 2 commands


Calibration using Anritsu "tee" #calibration #solt

 

I have access to an Anritsu VNA at my job, and with it we have the calibration "tee" which has open, short and load using N connectors. Would I make more accurate measurements using this for calibration or do the standards that come with the NanoVNA work well enough? Also, will using this for S-O-L but using the through that came with it have any adverse effect? Should I use an "N" through or will that make no difference?

Thanks for any help! I'm a decent tech but am definitely not anything close to an RF engineer lol!


Re: NanoVNA firmvare, compiled by DiSlord #firmware with MiniSD support #firmware

 

Hi Jos
I think you might ask DiSlord if the SD card driver supports SDHC type cards or the older type.?
Larry


Sent from Rogers Yahoo Mail on Android

On Sun, 24 May 2020 at 9:28 am, Jos Stevens<jrs@...> wrote: Hi DtSlord,

Thank you very much for the new firmware with microSD support, fantastic
!??? I have added the connector to my H-4 and flashed the firmware.

I have 2 questions? :

1 I tried to set the time by the new "time"command, but when I type
"time 2020 05 24 13 30 00", I get back : "Too many arguments, max 4".???
I tried several formats but no success, could you please give me the
correct format ?

2) I have one 8 GB microSD-HC card only , when I insert it and press the
bandwitdth display on the NanoVNA-H4, I get the error message :??
"SD_Send Cmd err CMD0, 0xFF , 0x00000000" twice and "CardType 0".?? Does
this mean that this card is not supported? ? It is empty and formatted
in FAT32.? I have ordered another card :? "Sandisc 32 GB Ultra
memorycard UHS-1 A1", ??? Will this one is will be Ok ?

In advance, thanks for your response.

Jos


Re: NanoVNA firmvare, compiled by DiSlord #firmware with MiniSD support #firmware

 

Flash last fitmware from this post
/g/nanovna-users/message/13787
In it i fix some problems

Time command syntac is:
time y 2020
time m 5
time d 24
time h 13
time min 30
time sec 10
"SD_Send Cmd err CMD0, 0xFF , 0x00000000" twice and "CardType 0"
Card not detected or answer, try update firmware


Re: NanoVNA firmvare, compiled by DiSlord #firmware with MiniSD support #firmware

 

Hi DtSlord,

Thank you very much for the new firmware with microSD support, fantastic !??? I have added the connector to my H-4 and flashed the firmware.

I have 2 questions? :

1 I tried to set the time by the new "time"command, but when I type "time 2020 05 24 13 30 00", I get back : "Too many arguments, max 4".??? I tried several formats but no success, could you please give me the correct format ?

2) I have one 8 GB microSD-HC card only , when I insert it and press the bandwitdth display on the NanoVNA-H4, I get the error message :?? "SD_Send Cmd err CMD0, 0xFF , 0x00000000" twice and "CardType 0".?? Does this mean that this card is not supported? ? It is empty and formatted in FAT32.? I have ordered another card :? "Sandisc 32 GB Ultra memorycard UHS-1 A1", ??? Will this one is will be Ok ?

In advance, thanks for your response.

Jos


Re: Homebrew sheilding

G7TAO
 

On Sat, May 23, 2020 at 02:04 PM, Dave B wrote:


round some srbp (Tufnol) formers THAT I made first.

Hello,

Have you got any images of the formers you made and any more close ups of your finished work? I've got a clone, non-shielded and wondered about adding something to it. Given the plethora of units on eBay I don't think I could have been sure to get one with shielding


Re: NanoVNA bricked

 

Hi folks,

I got a bricked VNA (white screen) from a very frustrated OM (very cheap: a glass of beer only, hi).
- First: I tried the "DfuSe"-way - no success - as expected.
- Second: I used the "STM32CubeProgrammer" and shortened Pin "VCC" with Pin "Boot0" to reach the programming mode. Using the concerning "nnn.hex" File - IT WORKS !
- Third: I tried the method which is decribed above with the ST-Link - IT WORKS also !
So nobody need a "sacrificial" device in his stock - I think. Give it away (for much more than one glass of beer only.., hi)
(I use WIN10 prof.)

Peter , DD6USB

P.S.
It was worth a glass of beer I think.......


Re: NanoVNA #calibration

 

What I see in the plot that you posted is a filter that is about 170 kHz wide at the -3 dB points and centered at 10.715 MHz. This is consistent with a Murata SFELF10M7HA00-B0 that has a spec of 180 +/-40 kHz and a center frequency of 10.7 MHz +/-30 kHz. The fact that all the filters exhibit the same response wouldn't surprise me if you purchased them at the same time, they probably came from the same batch, and the tolerance is likely based on batch to batch differences caused by process variations rather than random variations within a batch.

It is a little harder to understand/explain the fact that the low frequency side runs out of dynamic range at -60 dB and the high side gets there at 5 dB higher at -55 dB. Since these filters are symmetrical, have you tried swapping the input and output by turning the filter around at the fixture?

Also, you haven't really detailed your circuit for matching the 50 ohm of the VNA to the 330 ohm of the filter. If I were doing it, I would use a minimum loss matching pad. This would consist of a 54.281014769949586 ohm resistor (it is the value that the calculator gave - LOL) across the input and output coax to the VNA and a series resistor of 304.01167774007837 ohms up to the filter input/output. This would give a loss of 13.867585162369918 dB on each side. 5% values: 56 and 300. 1% values: 54.9 and 301. I am sure the 5% values would be just fine. You could bridge the filter location with a short on your test fixture to determine the exact loss through the pads, then place the filter in the fixture and easily find the filter insertion loss.


Re: NanoVNA-V2 Support Page

 

Who can increase the font size in the firmware?


Re: NanoVNA #calibration

 

Radu,
Please note there is a big difference between upper case C and lower case c as an indication of calibration.?
Refer to the User Guide in the Forum files section. I emphasized this in the section on calibration.?
If you see c0 instead of C0 then the unit is NOT calibrated. (The number can be 0 thru 4)
Remember to always press the Reset menu button before calibration and then Save to one of the memories ( 0 is the power-on recall default memory).?



On Sat, 23 May 2020 at 10:29 PM, Radu Bogdan Dicher<vondicher@...> wrote: Larry,
Thank you for your input. When I run the scan, I see "c1" on the top/left
side, and I'm always keeping it current.
That said, I just tried in both modes - RECALL 0, and RECALL 1 - and I
can't see a difference in the graph shape. Maybe my calibration hasn't been
successful?... Or, maybe this is a sign the device is defective?
Thank you,
Radu.


<>
Virus-free.
www.avg.com
<>
<#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>

On Sat, May 23, 2020 at 4:04 PM Larry Rothman <nlroth@...> wrote:

Please remember that if even if you've saved your new calibration to c1,
if you power cycle the Nano, it automatically recalls c0 and you need to
manually recall c1 every time you turn the unit ON

On top of that, many Nano units will power cycle when connected to USB
power.


? On Sat, 23 May 2020 at 6:56 PM, Radu Bogdan Dicher<vondicher@...>
wrote:? Just to document this a bit better - I placed my calibration data
on "c1,"
which I'm recalling (and I see on the left side of the screen, on top)
before running measurements. I calibrated for a CENTER of 10.7MHz, and a
SPAN of 1.4MHz. This was done with the cables in place, including the patch
extension (per guidelines), but my little kit that allows me to socket the
filters was not connected during calibration (I came to wonder if I should
do that).

To continue establishing the baseline of my setup, the kit has proper
termination for the filters (~330ohm) and cables (~50ohm), and also a 10pF
cap on the filters output (per Murata datasheet).


<

Virus-free.
www.avg.com
<

<#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>

On Sat, May 23, 2020 at 3:29 PM Radu Bogdan Dicher via groups.io
<vondicher=
[email protected]> wrote:

Hi all,
Having some confidence I've completed calibration on the band of interest
to me (I think I did 10MHz to 11MHz), I am getting the same titled scan
of
pretty much any number of filters I threw at this (I enclose a sample). I
am not sure if I need to return this, or request a replacement some other
way.
I contacted the seller (R&L), but it doesn't look like they have stock at
all and they haven't had any in a while.
[image: image.png]
Thank you all for you input.
Radu.

<

Virus-free.
www.avg.com
<

<#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>

On Wed, May 6, 2020 at 8:23 PM Radu Bogdan Dicher via groups.io
<vondicher=
[email protected]> wrote:

I think I figured it, a bit trial and error and such. The idea seems to
be
to turn off two traces out of four and make sure the two left follow
certain inputs (LOGMAG for each CH). Past this step, it's a bit weird
how
the calibration menu steps one ahead on you, making it a bit confusing
as
to whether it completed the previous step or not. But it seems the
traces
settle in a way that tells me the device read "itself" and calibrated
accordingly.

I'm repeating the procedure, as my 10.7MHz filters plots still lean
lower
on the left side. This is across multiple filters, can't be due to
them,
still think it's the device.

On Wed, May 6, 2020 at 7:41 PM Radu Bogdan Dicher via groups.io
<vondicher=
[email protected]> wrote:

I'm at the start of the calibration procedure, and I've connected
both
cables on CH0 and CH1, while using the pass-through attachment ("F-F
SMA"
in the v1.1 guidelines, in my interpretation) on the other end of the
SMA
cable coming from CH0.

The menu steps are clear until step 4, which calls for a "4. SINGLE."
I'm
not sure what this is. I don't see it anywhere following/around
TRACE 0
(which is there). I wonder if this is due to recent changes in the
menu
structure. Or maybe I am just missing something...

Thank you all for your help.
Radu.

On Tue, May 5, 2020 at 7:14 PM Radu Bogdan Dicher via groups.io
<vondicher=
[email protected]> wrote:

Thank you all.

Firstly - on the attachments. Paul: I guess by elimination works
great!
;)
In fact, makes complete sense and thank you.

Secondly - on the filters. Jim: yes, I am terminating the measuring
rig
properly by impedance matching (closest possible to 330ohm to
filters
and
50ohm to the NanoVNA). Even after eliminating unnecessary
complications (50ohm BNC cables, SMA adapters, etc.), the filters
response
is still screwy (though much improved), and this is across multiple
filters. I assume next step on this pursuit is to recalibrate. I
assume
this is probably about as good as factory calibration, so there's
not
much
to loose there.

Thirdly - on the manuals/files: Thank you for that repository, I
wasn't
aware of it!

Radu.

On Tue, May 5, 2020 at 6:37 PM Jim Allyn - N7JA <
jim@...>
wrote:

If the filters are not properly impedance matched, they will not
be
symmetrical.? In fact, the passband may be horribly distorted
compared
to
what you expect.? Further, the group delay of the filter will be
screwy,
which is important to those going for minimum distortion in their
FM
receivers.









<

Virus-free.
www.avg.com
<

<#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>



<

Virus-free.
www.avg.com
<

<#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>







<>
Virus-free.
www.avg.com
<>
<#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>


Re: NanoVNA firmvare, compiled by DiSlord #firmware

 

Hello,

You still need to compile it, but I have attached a nanovna-SAVER release that its compatible with the V2 and H4, with the addition of a small form
where one can add "attenuation" threshold to S21, courtesy from user @gaionim .

Luis, CT2FZI

On Fri, May 1, 2020 at 09:56 PM, DiSlord wrote:


Download NanoVNASaver development version from

Little fix Hardware.py to support H4 and 201 datapoint

All work good


Re: NanoVNA firmvare, compiled by DiSlord #firmware

 

Update NanoVNA H4 firmware to v0.9.1 beta

Work around errors in SD card support:
Cleanup my SD card support code
Implement read/write data CRC16 check
Implement command CRC7 check
Fix SPI bus problems
Enable support short and long filenames
Now firmware have beta status and look stable (at this time no errors on read/write on my test card while made 100 screenshots)
Debug console log still present, need for support


Frequency error during warm-up

 

I measured the CW frequency error during "my" NanoVNA warm-up.

Without the DiSlord's installed FW, the actual error would be shifted higher !

May be not a TCXO but XO as i wrote in a past message.

Error during assembly ? Cost reason ? They are just assumptions.

Rudi

PS As i don't have a temperature sensor to measure the internal

closed NanoVNA-H value, i'v just measured the elapsed time since power-up.

(Sorry for my English language)


Re: NanoVNA large font feature request.

 

Looks like it's on its way into Hugen's NanoVNA-H:



Just checked my NanoVNA-H Feb 21 2020 firmware and i don't see that menu
yet.



Thanks,

Chris.

On Sun, May 24, 2020 at 12:29 PM Chris Keladis via groups.io <ckeladis=
[email protected]> wrote:

Thanks Larry, will submit there.



Chris.

On Sun, 24 May 2020, 11:57 am Larry Rothman, <nlroth@...> wrote:

A much better place for feature requests is in the GitHub repo for the
individual developers where it can be commented on and tracked.



On Sat, 23 May 2020 at 9:05 PM, Chris Keladis<ckeladis@...>
wrote: Was just reading about Reald's "big font overlay" feature from
his
firmware, looks something like this:

[image: image.png]

This is great to have as a standard feature in all firmwares. Would also
be
useful on 4" displays as well.

I know Hugen and others are on the list so just wanted to submit this as
a
feature request ::)




Thanks,

Chris.










Re: NanoVNA #calibration

 

Larry,
Thank you for your input. When I run the scan, I see "c1" on the top/left
side, and I'm always keeping it current.
That said, I just tried in both modes - RECALL 0, and RECALL 1 - and I
can't see a difference in the graph shape. Maybe my calibration hasn't been
successful?... Or, maybe this is a sign the device is defective?
Thank you,
Radu.


<>
Virus-free.
www.avg.com
<>
<#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>

On Sat, May 23, 2020 at 4:04 PM Larry Rothman <nlroth@...> wrote:

Please remember that if even if you've saved your new calibration to c1,
if you power cycle the Nano, it automatically recalls c0 and you need to
manually recall c1 every time you turn the unit ON

On top of that, many Nano units will power cycle when connected to USB
power.


On Sat, 23 May 2020 at 6:56 PM, Radu Bogdan Dicher<vondicher@...>
wrote: Just to document this a bit better - I placed my calibration data
on "c1,"
which I'm recalling (and I see on the left side of the screen, on top)
before running measurements. I calibrated for a CENTER of 10.7MHz, and a
SPAN of 1.4MHz. This was done with the cables in place, including the patch
extension (per guidelines), but my little kit that allows me to socket the
filters was not connected during calibration (I came to wonder if I should
do that).

To continue establishing the baseline of my setup, the kit has proper
termination for the filters (~330ohm) and cables (~50ohm), and also a 10pF
cap on the filters output (per Murata datasheet).


<

Virus-free.
www.avg.com
<

<#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>

On Sat, May 23, 2020 at 3:29 PM Radu Bogdan Dicher via groups.io
<vondicher=
[email protected]> wrote:

Hi all,
Having some confidence I've completed calibration on the band of interest
to me (I think I did 10MHz to 11MHz), I am getting the same titled scan
of
pretty much any number of filters I threw at this (I enclose a sample). I
am not sure if I need to return this, or request a replacement some other
way.
I contacted the seller (R&L), but it doesn't look like they have stock at
all and they haven't had any in a while.
[image: image.png]
Thank you all for you input.
Radu.

<

Virus-free.
www.avg.com
<

<#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>

On Wed, May 6, 2020 at 8:23 PM Radu Bogdan Dicher via groups.io
<vondicher=
[email protected]> wrote:

I think I figured it, a bit trial and error and such. The idea seems to
be
to turn off two traces out of four and make sure the two left follow
certain inputs (LOGMAG for each CH). Past this step, it's a bit weird
how
the calibration menu steps one ahead on you, making it a bit confusing
as
to whether it completed the previous step or not. But it seems the
traces
settle in a way that tells me the device read "itself" and calibrated
accordingly.

I'm repeating the procedure, as my 10.7MHz filters plots still lean
lower
on the left side. This is across multiple filters, can't be due to
them,
still think it's the device.

On Wed, May 6, 2020 at 7:41 PM Radu Bogdan Dicher via groups.io
<vondicher=
[email protected]> wrote:

I'm at the start of the calibration procedure, and I've connected
both
cables on CH0 and CH1, while using the pass-through attachment ("F-F
SMA"
in the v1.1 guidelines, in my interpretation) on the other end of the
SMA
cable coming from CH0.

The menu steps are clear until step 4, which calls for a "4. SINGLE."
I'm
not sure what this is. I don't see it anywhere following/around
TRACE 0
(which is there). I wonder if this is due to recent changes in the
menu
structure. Or maybe I am just missing something...

Thank you all for your help.
Radu.

On Tue, May 5, 2020 at 7:14 PM Radu Bogdan Dicher via groups.io
<vondicher=
[email protected]> wrote:

Thank you all.

Firstly - on the attachments. Paul: I guess by elimination works
great!
;)
In fact, makes complete sense and thank you.

Secondly - on the filters. Jim: yes, I am terminating the measuring
rig
properly by impedance matching (closest possible to 330ohm to
filters
and
50ohm to the NanoVNA). Even after eliminating unnecessary
complications (50ohm BNC cables, SMA adapters, etc.), the filters
response
is still screwy (though much improved), and this is across multiple
filters. I assume next step on this pursuit is to recalibrate. I
assume
this is probably about as good as factory calibration, so there's
not
much
to loose there.

Thirdly - on the manuals/files: Thank you for that repository, I
wasn't
aware of it!

Radu.

On Tue, May 5, 2020 at 6:37 PM Jim Allyn - N7JA <
jim@...>
wrote:

If the filters are not properly impedance matched, they will not
be
symmetrical. In fact, the passband may be horribly distorted
compared
to
what you expect. Further, the group delay of the filter will be
screwy,
which is important to those going for minimum distortion in their
FM
receivers.









<

Virus-free.
www.avg.com
<

<#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>



<

Virus-free.
www.avg.com
<

<#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>







<>
Virus-free.
www.avg.com
<>
<#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>


Re: NanoVNA large font feature request.

 

Thanks Larry, will submit there.



Chris.

On Sun, 24 May 2020, 11:57 am Larry Rothman, <nlroth@...> wrote:

A much better place for feature requests is in the GitHub repo for the
individual developers where it can be commented on and tracked.



On Sat, 23 May 2020 at 9:05 PM, Chris Keladis<ckeladis@...>
wrote: Was just reading about Reald's "big font overlay" feature from his
firmware, looks something like this:

[image: image.png]

This is great to have as a standard feature in all firmwares. Would also be
useful on 4" displays as well.

I know Hugen and others are on the list so just wanted to submit this as a
feature request ::)




Thanks,

Chris.








Re: NanoVNA large font feature request.

 

A much better place for feature requests is in the GitHub repo for the individual developers where it can be commented on and tracked.?



On Sat, 23 May 2020 at 9:05 PM, Chris Keladis<ckeladis@...> wrote: Was just reading about Reald's "big font overlay" feature from his
firmware, looks something like this:

[image: image.png]

This is great to have as a standard feature in all firmwares. Would also be
useful on 4" displays as well.

I know Hugen and others are on the list so just wanted to submit this as a
feature request ::)




Thanks,

Chris.


NanoVNA large font feature request.

 

Was just reading about Reald's "big font overlay" feature from his
firmware, looks something like this:

[image: image.png]

This is great to have as a standard feature in all firmwares. Would also be
useful on 4" displays as well.

I know Hugen and others are on the list so just wanted to submit this as a
feature request ::)




Thanks,

Chris.


Re: NanoVNA #calibration

 

Please remember that if even if you've saved your new calibration to c1, if you power cycle the Nano, it automatically recalls c0 and you need to manually recall c1 every time you turn the unit ON

On top of that, many Nano units will power cycle when connected to USB power.?


On Sat, 23 May 2020 at 6:56 PM, Radu Bogdan Dicher<vondicher@...> wrote: Just to document this a bit better - I placed my calibration data on "c1,"
which I'm recalling (and I see on the left side of the screen, on top)
before running measurements. I calibrated for a CENTER of 10.7MHz, and a
SPAN of 1.4MHz. This was done with the cables in place, including the patch
extension (per guidelines), but my little kit that allows me to socket the
filters was not connected during calibration (I came to wonder if I should
do that).

To continue establishing the baseline of my setup, the kit has proper
termination for the filters (~330ohm) and cables (~50ohm), and also a 10pF
cap on the filters output (per Murata datasheet).


<>
Virus-free.
www.avg.com
<>
<#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>

On Sat, May 23, 2020 at 3:29 PM Radu Bogdan Dicher via groups.io <vondicher=
[email protected]> wrote:

Hi all,
Having some confidence I've completed calibration on the band of interest
to me (I think I did 10MHz to 11MHz), I am getting the same titled scan of
pretty much any number of filters I threw at this (I enclose a sample). I
am not sure if I need to return this, or request a replacement some other
way.
I contacted the seller (R&L), but it doesn't look like they have stock at
all and they haven't had any in a while.
[image: image.png]
Thank you all for you input.
Radu.

<

Virus-free.
www.avg.com
<

<#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>

On Wed, May 6, 2020 at 8:23 PM Radu Bogdan Dicher via groups.io
<vondicher=
[email protected]> wrote:

I think I figured it, a bit trial and error and such. The idea seems to
be
to turn off two traces out of four and make sure the two left follow
certain inputs (LOGMAG for each CH). Past this step, it's a bit weird how
the calibration menu steps one ahead on you, making it a bit confusing as
to whether it completed the previous step or not. But it seems the traces
settle in a way that tells me the device read "itself" and calibrated
accordingly.

I'm repeating the procedure, as my 10.7MHz filters plots still lean lower
on the left side. This is across multiple filters, can't be due to them,
still think it's the device.

On Wed, May 6, 2020 at 7:41 PM Radu Bogdan Dicher via groups.io
<vondicher=
[email protected]> wrote:

I'm at the start of the calibration procedure, and I've connected both
cables on CH0 and CH1, while using the pass-through attachment ("F-F
SMA"
in the v1.1 guidelines, in my interpretation) on the other end of the
SMA
cable coming from CH0.

The menu steps are clear until step 4, which calls for a "4. SINGLE."
I'm
not sure what this is. I don't see it anywhere following/around TRACE 0
(which is there). I wonder if this is due to recent changes in the menu
structure. Or maybe I am just missing something...

Thank you all for your help.
Radu.

On Tue, May 5, 2020 at 7:14 PM Radu Bogdan Dicher via groups.io
<vondicher=
[email protected]> wrote:

Thank you all.

Firstly - on the attachments. Paul: I guess by elimination works
great!
;)
In fact, makes complete sense and thank you.

Secondly - on the filters. Jim: yes, I am terminating the measuring
rig
properly by impedance matching (closest possible to 330ohm to filters
and
50ohm to the NanoVNA). Even after eliminating unnecessary
complications (50ohm BNC cables, SMA adapters, etc.), the filters
response
is still screwy (though much improved), and this is across multiple
filters. I assume next step on this pursuit is to recalibrate. I
assume
this is probably about as good as factory calibration, so there's not
much
to loose there.

Thirdly - on the manuals/files: Thank you for that repository, I
wasn't
aware of it!

Radu.

On Tue, May 5, 2020 at 6:37 PM Jim Allyn - N7JA <
jim@...>
wrote:

If the filters are not properly impedance matched, they will not be
symmetrical.? In fact, the passband may be horribly distorted
compared
to
what you expect.? Further, the group delay of the filter will be
screwy,
which is important to those going for minimum distortion in their
FM
receivers.









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