Re: updated and calibrated nanovna h4 yields incorrect swr readings
Hello Stan,
What model, manufacurer and from what supplier did you obtain the quality sma coax cables?
Thanks.
Al
|
Re: updated and calibrated nanovna h4 yields incorrect swr readings
Not me, but..... Pasternack is a good supplier, although a bit pricey.
I believe DigiKey also carries their products.
Dave - W?LEV
toggle quoted message
Show quoted text
On Wed, Sep 6, 2023 at 9:42?PM Allan Johnston <adhjohnston@...> wrote: Hello Stan,
What model, manufacurer and from what supplier did you obtain the quality
sma coax cables?
Thanks.
Al
On Wed, Sep 6, 2023, 4:11 PM Stan Dye <standye@...> wrote:
It is not uncommon for the sma-terminated pigtail cables that come with the
nanovna to fail, or to not have been assembled well. Sometimes the shield
is not soldered at the connector, so it passes test at the factory, but
fails the first time you bend it. I ordered a set of better sma pigtail
cables, and haven't had a problem with them.
On Wed, Sep 6, 2023, 2:51 PM Allan Johnston <adhjohnston@...> wrote:
Dave, W0LEV,
It's looking like an intermittent good then bad connection with the
NanoVNA.
The nanovna is connected with the unit's supplied connectors/coax and
additional connector as needed for the antenna.
See attached "nanovna usual bad trace" jpeg that shows the connectors.
The RigExpert connection does not include the small diameter nanovna
coax
cable.
As I set up the RigExpert and NanoVNA for review and photos I
discovered
the flaky intermittent connection in the run of small coax and connectors.
The bad connection is so random that I cannot tell what connector is
the
problem.
More hunting!
Thank you for your response. Your questions helped me discover what is
biting me. At least I know the NanoVNA is working.
If you or anyone else has comments on the trace or the
equipment/coax/connector setup that may help me out then please don't
hesitate to respond.
Al. KA0VIA
On Wed, Sep 6, 2023 at 12:31?PM W0LEV <davearea51a@...> wrote:
How are you connecting the NANOVNA? Identical to the method used for the
RigExpert? Where does the trace show on the Smith Chart of the
NANOVNA?
Is the trace consistent with the SWR indication?
Once your NANOVNA is calibrated, have you gone back with your cal.
standards and verified the calibration took correctly? Have you
verified
your cal. standards on the RigExpert or some other method?
I know.....just a bunch of questions, but I'm searching for possible
problems.
Dave - W?LEV
On Wed, Sep 6, 2023 at 5:27?PM Allan Johnston <adhjohnston@...
wrote:
The Nanovna h4 in use was purchased from R&L Electronics a year or
so
ago.
Last month I updated the software.
The Nanovna has never given me "good" results as compared to a RigExpert
AA 650 zoom when measuring HF, VHF or UHF antennas.
The Nanovna has been calibrated for each frequency range. The
RigExpert
AA-650 zoom passes the self test.
Example; the Rigexpert reads a SWR of close to 1:1 for a 2 meter
antenna
that is externally mounted while the Nanovna results show 50:1.
Any ideas?
Thanks,
Al, KA0VIA
--
*Dave - W?LEV*
--
Dave - W?LEV
-- *Dave - W?LEV*
--
Dave - W?LEV
|
Re: updated and calibrated nanovna h4 yields incorrect swr readings
Hello Stan,
What model, manufacurer and from what supplier did you obtain the quality
sma coax cables?
Thanks.
Al
toggle quoted message
Show quoted text
On Wed, Sep 6, 2023, 4:11 PM Stan Dye <standye@...> wrote: It is not uncommon for the sma-terminated pigtail cables that come with the
nanovna to fail, or to not have been assembled well. Sometimes the shield
is not soldered at the connector, so it passes test at the factory, but
fails the first time you bend it. I ordered a set of better sma pigtail
cables, and haven't had a problem with them.
On Wed, Sep 6, 2023, 2:51 PM Allan Johnston <adhjohnston@...> wrote:
Dave, W0LEV,
It's looking like an intermittent good then bad connection with the
NanoVNA.
The nanovna is connected with the unit's supplied connectors/coax and
additional connector as needed for the antenna.
See attached "nanovna usual bad trace" jpeg that shows the connectors.
The RigExpert connection does not include the small diameter nanovna coax
cable.
As I set up the RigExpert and NanoVNA for review and photos I discovered
the flaky intermittent connection in the run of small coax and connectors.
The bad connection is so random that I cannot tell what connector is the
problem.
More hunting!
Thank you for your response. Your questions helped me discover what is
biting me. At least I know the NanoVNA is working.
If you or anyone else has comments on the trace or the
equipment/coax/connector setup that may help me out then please don't
hesitate to respond.
Al. KA0VIA
On Wed, Sep 6, 2023 at 12:31?PM W0LEV <davearea51a@...> wrote:
How are you connecting the NANOVNA? Identical to the method used for the
RigExpert? Where does the trace show on the Smith Chart of the
NANOVNA?
Is the trace consistent with the SWR indication?
Once your NANOVNA is calibrated, have you gone back with your cal.
standards and verified the calibration took correctly? Have you
verified
your cal. standards on the RigExpert or some other method?
I know.....just a bunch of questions, but I'm searching for possible
problems.
Dave - W?LEV
On Wed, Sep 6, 2023 at 5:27?PM Allan Johnston <adhjohnston@...>
wrote:
The Nanovna h4 in use was purchased from R&L Electronics a year or so ago.
Last month I updated the software.
The Nanovna has never given me "good" results as compared to a RigExpert
AA 650 zoom when measuring HF, VHF or UHF antennas.
The Nanovna has been calibrated for each frequency range. The
RigExpert
AA-650 zoom passes the self test.
Example; the Rigexpert reads a SWR of close to 1:1 for a 2 meter
antenna
that is externally mounted while the Nanovna results show 50:1.
Any ideas?
Thanks,
Al, KA0VIA
--
*Dave - W?LEV*
--
Dave - W?LEV
|
Re: updated and calibrated nanovna h4 yields incorrect swr readings
Glad you found the problem. These cables have been problematic from day
one. I've even had a few with the NANOVNAs. Even a few bad USB cables.
Dsve - W?LEV
toggle quoted message
Show quoted text
On Wed, Sep 6, 2023 at 8:51?PM Allan Johnston <adhjohnston@...> wrote: Dave, W0LEV,
It's looking like an intermittent good then bad connection with the
NanoVNA.
The nanovna is connected with the unit's supplied connectors/coax and
additional connector as needed for the antenna.
See attached "nanovna usual bad trace" jpeg that shows the connectors.
The RigExpert connection does not include the small diameter nanovna coax
cable.
As I set up the RigExpert and NanoVNA for review and photos I discovered
the flaky intermittent connection in the run of small coax and connectors.
The bad connection is so random that I cannot tell what connector is the
problem.
More hunting!
Thank you for your response. Your questions helped me discover what is
biting me. At least I know the NanoVNA is working.
If you or anyone else has comments on the trace or the
equipment/coax/connector setup that may help me out then please don't
hesitate to respond.
Al. KA0VIA
On Wed, Sep 6, 2023 at 12:31?PM W0LEV <davearea51a@...> wrote:
How are you connecting the NANOVNA? Identical to the method used for the
RigExpert? Where does the trace show on the Smith Chart of the NANOVNA?
Is the trace consistent with the SWR indication?
Once your NANOVNA is calibrated, have you gone back with your cal.
standards and verified the calibration took correctly? Have you verified
your cal. standards on the RigExpert or some other method?
I know.....just a bunch of questions, but I'm searching for possible
problems.
Dave - W?LEV
On Wed, Sep 6, 2023 at 5:27?PM Allan Johnston <adhjohnston@...>
wrote:
The Nanovna h4 in use was purchased from R&L Electronics a year or so ago.
Last month I updated the software.
The Nanovna has never given me "good" results as compared to a RigExpert
AA 650 zoom when measuring HF, VHF or UHF antennas.
The Nanovna has been calibrated for each frequency range. The RigExpert
AA-650 zoom passes the self test.
Example; the Rigexpert reads a SWR of close to 1:1 for a 2 meter
antenna
that is externally mounted while the Nanovna results show 50:1.
Any ideas?
Thanks,
Al, KA0VIA
--
*Dave - W?LEV*
--
Dave - W?LEV
-- *Dave - W?LEV*
--
Dave - W?LEV
|
Re: updated and calibrated nanovna h4 yields incorrect swr readings
It is not uncommon for the sma-terminated pigtail cables that come with the
nanovna to fail, or to not have been assembled well. Sometimes the shield
is not soldered at the connector, so it passes test at the factory, but
fails the first time you bend it. I ordered a set of better sma pigtail
cables, and haven't had a problem with them.
toggle quoted message
Show quoted text
On Wed, Sep 6, 2023, 2:51 PM Allan Johnston <adhjohnston@...> wrote: Dave, W0LEV,
It's looking like an intermittent good then bad connection with the
NanoVNA.
The nanovna is connected with the unit's supplied connectors/coax and
additional connector as needed for the antenna.
See attached "nanovna usual bad trace" jpeg that shows the connectors.
The RigExpert connection does not include the small diameter nanovna coax
cable.
As I set up the RigExpert and NanoVNA for review and photos I discovered
the flaky intermittent connection in the run of small coax and connectors.
The bad connection is so random that I cannot tell what connector is the
problem.
More hunting!
Thank you for your response. Your questions helped me discover what is
biting me. At least I know the NanoVNA is working.
If you or anyone else has comments on the trace or the
equipment/coax/connector setup that may help me out then please don't
hesitate to respond.
Al. KA0VIA
On Wed, Sep 6, 2023 at 12:31?PM W0LEV <davearea51a@...> wrote:
How are you connecting the NANOVNA? Identical to the method used for the
RigExpert? Where does the trace show on the Smith Chart of the NANOVNA?
Is the trace consistent with the SWR indication?
Once your NANOVNA is calibrated, have you gone back with your cal.
standards and verified the calibration took correctly? Have you verified
your cal. standards on the RigExpert or some other method?
I know.....just a bunch of questions, but I'm searching for possible
problems.
Dave - W?LEV
On Wed, Sep 6, 2023 at 5:27?PM Allan Johnston <adhjohnston@...>
wrote:
The Nanovna h4 in use was purchased from R&L Electronics a year or so ago.
Last month I updated the software.
The Nanovna has never given me "good" results as compared to a RigExpert
AA 650 zoom when measuring HF, VHF or UHF antennas.
The Nanovna has been calibrated for each frequency range. The RigExpert
AA-650 zoom passes the self test.
Example; the Rigexpert reads a SWR of close to 1:1 for a 2 meter
antenna
that is externally mounted while the Nanovna results show 50:1.
Any ideas?
Thanks,
Al, KA0VIA
--
*Dave - W?LEV*
--
Dave - W?LEV
|
Re: updated and calibrated nanovna h4 yields incorrect swr readings
Dave, W0LEV,
It's looking like an intermittent good then bad connection with the NanoVNA.
The nanovna is connected with the unit's supplied connectors/coax and
additional connector as needed for the antenna.
See attached "nanovna usual bad trace" jpeg that shows the connectors.
The RigExpert connection does not include the small diameter nanovna coax
cable.
As I set up the RigExpert and NanoVNA for review and photos I discovered
the flaky intermittent connection in the run of small coax and connectors.
The bad connection is so random that I cannot tell what connector is the
problem.
More hunting!
Thank you for your response. Your questions helped me discover what is
biting me. At least I know the NanoVNA is working.
If you or anyone else has comments on the trace or the
equipment/coax/connector setup that may help me out then please don't
hesitate to respond.
Al. KA0VIA
toggle quoted message
Show quoted text
On Wed, Sep 6, 2023 at 12:31?PM W0LEV <davearea51a@...> wrote: How are you connecting the NANOVNA? Identical to the method used for the
RigExpert? Where does the trace show on the Smith Chart of the NANOVNA?
Is the trace consistent with the SWR indication?
Once your NANOVNA is calibrated, have you gone back with your cal.
standards and verified the calibration took correctly? Have you verified
your cal. standards on the RigExpert or some other method?
I know.....just a bunch of questions, but I'm searching for possible
problems.
Dave - W?LEV
On Wed, Sep 6, 2023 at 5:27?PM Allan Johnston <adhjohnston@...>
wrote:
The Nanovna h4 in use was purchased from R&L Electronics a year or so ago.
Last month I updated the software.
The Nanovna has never given me "good" results as compared to a RigExpert
AA 650 zoom when measuring HF, VHF or UHF antennas.
The Nanovna has been calibrated for each frequency range. The RigExpert
AA-650 zoom passes the self test.
Example; the Rigexpert reads a SWR of close to 1:1 for a 2 meter antenna
that is externally mounted while the Nanovna results show 50:1.
Any ideas?
Thanks,
Al, KA0VIA
--
*Dave - W?LEV*
--
Dave - W?LEV
|
Re: Nano VNA of a modified 40m hor loop NVIS antenna
Thank you for the reply. I¡¯m a long time NVIS emcomm loop user but I just moved and purchased the H4 to build a new loop for 80 and another for 40. I¡¯ve had excellent success using the 10KW common mode 1:1 coax to ladder line balun from DXE with a short run of LMR400 to the outside and then the ladder up to the loop. JJ Knight N5MNX ________________________________ From: [email protected] < [email protected]> on behalf of W0LEV <davearea51a@...> Sent: Wednesday, September 6, 2023 12:12:55 PM To: [email protected] < [email protected]> Subject: Re: [nanovna-users] Nano VNA of a modified 40m hor loop NVIS antenna 40-meters between your target times of 1000 to 1400 local will be problematic if the fof2 is not at or above 7-MHz. Here in N. Colorado, of late, it has been, but over the last couple of years during the lull between Solar Cycles 24 and 25, NVIS was impossible due to the low fof2 which came in lower than 5 MHz. For a look at the fof2 in your area, check the following: <> Of course, I regularly use the Boulder, Colorado, ionogram as it's only some 30-miles to my south. Dave - W?LEV On Wed, Sep 6, 2023 at 11:58?AM Barry K3EUI <k3euibarry@...> wrote: JJ Night
To answer your question¡
There is nothing special about this antenna, other than it is a closed
LOOP of 140 ft heavy wire #10 because I had a few hundred feet of this wire.
I wanted good daytime NVIS antenna for prop of only a few hundred miles
from Phila around 10AM to 2 PM.
I was not interested in a low-angle DX signal for evening use (I have a
vertical that does that well)
The amount of wire did not matter too much (120-140 ft to start).
I feed this with about 75 ft of RG213 (nothing special)
The shape is a rectangle, only 20 ft or so above ground. I had a few big
strong trees as tie points.
I tried a 4:1 balun at first (thinking impedance of 100 ohms) and that did
not work well.
I replaced that with a simple 1:1 BALUN (choke).
At the low height above ground, I expected a lower impedance than putting
it up 50 ft.
I could attach the Nano VNA right at the feedpoint - direct - to avoid the
feedline messing with impedance.
I then hooked it up to a CLC Tuner (in my shack) in case the SWR was high
at the digi part of the band.
Because I had about 140 ft wire in the loop, the resonant point was just
below 7 MHz (about 6.8 MHz).
It worked fine for two weeks, but then I thought maybe I could improve it
by shortening it.
I pruned it back about 10 feet (harder to do for me on a 90 degree day)
and then I saw that the minimum SWR fell around 7.1 MHz, right where I
wanted it.
The NANO VNA that I own is already 3 years old (Amazon model) and I¡¯m
using NANO VNA SAVER app on a Win10 (10 yr old) desktop. I had to make the
CALIB first with a 3-30 MHz span at a 10x mag. That took a few minutes to
do the OPEN, SHORT, and 50 0hm LOAD with the standards that came with the
rig.
I did a sweep from 3-30 MHz using the 50 ohm standard and everything
looked perfect on the 6 graphs.
That was reassuring!
The closed loop works far better than a pair of Hamsticks mounted
horizontally (14 ft total). Well, obviously!
It works just about as well as a simple 66 ft Inverted V center-fed dipole
(my standard) but I see much less QSB on the closed loop than from the
dipole. I like to use 7047 kHz W1AW CW bulletins as my standard to compare
antennas at 9AM to 10AM. And¡ it helps me copy CW by ear.
So nothing special about anything that I did.
I put in a CLC tuner in my shack, and this does sharpen up all of the
graphs, but I did not really need it.
My goal: see if I could build a better DAYTIME NVIS antenna for low part
of the 40m band.
I love the sound card digi modes and FLDIGI and am working on a new 40m
EMCOMM digi mode net which should begin on October 1st: Mid-Atlantic 40m
NBEMS net (7068 kHz vfo).
We plan to run this net every Sunday at 10AM to 11AM for a few months to
see how well ¡°fickle forty¡± does at that hour with THOR22 (checkin) and
THOR56 (traffic). We know that 80m collapses by 10 AM for NVIS.
I really did not need a Nano VNA to build and test this antenna. I am now
doing A/B tests to see if folks I work on 40m digi modes can hear any
differences between the closed loop and Inverted V simple dipole.
I took the back-to-back Hamsticks down (may be good for a portable setup)
And I still have a 36 ft vertical with two above ground radials (upside
down T) for evening DX.
What are you trying to accomplish in your antenna?
Without the SAVER software, I¡¯d be lost (color blind).
de k3eui Barry
near Philly
Sept 06 2023
-- *Dave - W?LEV* -- Dave - W?LEV
|
Re: updated and calibrated nanovna h4 yields incorrect swr readings
How are you connecting the NANOVNA? Identical to the method used for the
RigExpert? Where does the trace show on the Smith Chart of the NANOVNA?
Is the trace consistent with the SWR indication?
Once your NANOVNA is calibrated, have you gone back with your cal.
standards and verified the calibration took correctly? Have you verified
your cal. standards on the RigExpert or some other method?
I know.....just a bunch of questions, but I'm searching for possible
problems.
Dave - W?LEV
toggle quoted message
Show quoted text
On Wed, Sep 6, 2023 at 5:27?PM Allan Johnston <adhjohnston@...> wrote: The Nanovna h4 in use was purchased from R&L Electronics a year or so ago.
Last month I updated the software.
The Nanovna has never given me "good" results as compared to a RigExpert
AA 650 zoom when measuring HF, VHF or UHF antennas.
The Nanovna has been calibrated for each frequency range. The RigExpert
AA-650 zoom passes the self test.
Example; the Rigexpert reads a SWR of close to 1:1 for a 2 meter antenna
that is externally mounted while the Nanovna results show 50:1.
Any ideas?
Thanks,
Al, KA0VIA
-- *Dave - W?LEV*
--
Dave - W?LEV
|
updated and calibrated nanovna h4 yields incorrect swr readings
The Nanovna h4 in use was purchased from R&L Electronics a year or so ago.
Last month I updated the software.
The Nanovna has never given me "good" results as compared to a RigExpert AA 650 zoom when measuring HF, VHF or UHF antennas.
The Nanovna has been calibrated for each frequency range. The RigExpert AA-650 zoom passes the self test.
Example; the Rigexpert reads a SWR of close to 1:1 for a 2 meter antenna that is externally mounted while the Nanovna results show 50:1.
Any ideas?
Thanks,
Al, KA0VIA
|
Re: Nano VNA of a modified 40m hor loop NVIS antenna
40-meters between your target times of 1000 to 1400 local will be
problematic if the fof2 is not at or above 7-MHz. Here in N. Colorado, of
late, it has been, but over the last couple of years during the lull
between Solar Cycles 24 and 25, NVIS was impossible due to the low fof2
which came in lower than 5 MHz. For a look at the fof2 in your area, check
the following:
Of course, I regularly use the Boulder, Colorado, ionogram as it's only
some 30-miles to my south.
Dave - W?LEV
toggle quoted message
Show quoted text
On Wed, Sep 6, 2023 at 11:58?AM Barry K3EUI <k3euibarry@...> wrote: JJ Night
To answer your question¡
There is nothing special about this antenna, other than it is a closed
LOOP of 140 ft heavy wire #10 because I had a few hundred feet of this wire.
I wanted good daytime NVIS antenna for prop of only a few hundred miles
from Phila around 10AM to 2 PM.
I was not interested in a low-angle DX signal for evening use (I have a
vertical that does that well)
The amount of wire did not matter too much (120-140 ft to start).
I feed this with about 75 ft of RG213 (nothing special)
The shape is a rectangle, only 20 ft or so above ground. I had a few big
strong trees as tie points.
I tried a 4:1 balun at first (thinking impedance of 100 ohms) and that did
not work well.
I replaced that with a simple 1:1 BALUN (choke).
At the low height above ground, I expected a lower impedance than putting
it up 50 ft.
I could attach the Nano VNA right at the feedpoint - direct - to avoid the
feedline messing with impedance.
I then hooked it up to a CLC Tuner (in my shack) in case the SWR was high
at the digi part of the band.
Because I had about 140 ft wire in the loop, the resonant point was just
below 7 MHz (about 6.8 MHz).
It worked fine for two weeks, but then I thought maybe I could improve it
by shortening it.
I pruned it back about 10 feet (harder to do for me on a 90 degree day)
and then I saw that the minimum SWR fell around 7.1 MHz, right where I
wanted it.
The NANO VNA that I own is already 3 years old (Amazon model) and I¡¯m
using NANO VNA SAVER app on a Win10 (10 yr old) desktop. I had to make the
CALIB first with a 3-30 MHz span at a 10x mag. That took a few minutes to
do the OPEN, SHORT, and 50 0hm LOAD with the standards that came with the
rig.
I did a sweep from 3-30 MHz using the 50 ohm standard and everything
looked perfect on the 6 graphs.
That was reassuring!
The closed loop works far better than a pair of Hamsticks mounted
horizontally (14 ft total). Well, obviously!
It works just about as well as a simple 66 ft Inverted V center-fed dipole
(my standard) but I see much less QSB on the closed loop than from the
dipole. I like to use 7047 kHz W1AW CW bulletins as my standard to compare
antennas at 9AM to 10AM. And¡ it helps me copy CW by ear.
So nothing special about anything that I did.
I put in a CLC tuner in my shack, and this does sharpen up all of the
graphs, but I did not really need it.
My goal: see if I could build a better DAYTIME NVIS antenna for low part
of the 40m band.
I love the sound card digi modes and FLDIGI and am working on a new 40m
EMCOMM digi mode net which should begin on October 1st: Mid-Atlantic 40m
NBEMS net (7068 kHz vfo).
We plan to run this net every Sunday at 10AM to 11AM for a few months to
see how well ¡°fickle forty¡± does at that hour with THOR22 (checkin) and
THOR56 (traffic). We know that 80m collapses by 10 AM for NVIS.
I really did not need a Nano VNA to build and test this antenna. I am now
doing A/B tests to see if folks I work on 40m digi modes can hear any
differences between the closed loop and Inverted V simple dipole.
I took the back-to-back Hamsticks down (may be good for a portable setup)
And I still have a 36 ft vertical with two above ground radials (upside
down T) for evening DX.
What are you trying to accomplish in your antenna?
Without the SAVER software, I¡¯d be lost (color blind).
de k3eui Barry
near Philly
Sept 06 2023
-- *Dave - W?LEV*
--
Dave - W?LEV
|
Re: Nano VNA of a modified 40m hor loop NVIS antenna
Capacitor,inductor,capacitor Ok... with a capacitor, inductor, capacitor + inducteur you can do a fixed two band matching network :) Thank -- F1AMM Fran?ois -----Message d'origine----- De la part de Jim Lux Envoy¨¦ : mercredi 6 septembre 2023 15:49
|
Re: Nano VNA of a modified 40m hor loop NVIS antenna
a closed LOOP of 140 ft heavy wire #10
I feed this with about 75 ft of RG213 (nothing special)
The shape is a rectangle, only 20 ft or so above ground. I have almost the same antenna as you. Over 40 m no station arrives harder than on my trap doublet at 12 m height. In general, a station arrives between -6dB and -10dB on the loop than on the doublet. In the other direction, for the correspondent, the observation is the same. On the other hand, in reception, I almost always notice an improvement in the signal-to-noise ratio. I am thinking that no NVIS propagation is possible in my region (France) over 40 m. In France, the 1 to 6 MHz band is generally usable for NVIS propagation, while in the tropics it is rather the 4 to 12 MHz band () Is it possible on Philadelphie ? Over 20 m (14 MHz) this antenna significantly improves the received signal, often by +6dB to +10dB. I was not able to reliably test the signal received from my correspondent.... The antenna is equipped, at the coaxial cable / antenna connection, with a double 'L' adapter of my design - production. 73 -- Fran?ois -----Message d'origine----- De la part de Barry K3EUI Envoy¨¦ : mercredi 6 septembre 2023 13:59
|
Re: Nano VNA of a modified 40m hor loop NVIS antenna
Capacitor,inductor,capacitor
toggle quoted message
Show quoted text
On Sep 6, 2023, at 6:10 AM, Fran?ois <18471@...> wrote:
?
I put in a CLC tuner in my shack,
Please wat is a "CLC tuner" ?
--
F1AMM
Fran?ois
-----Message d'origine----- De la part de Barry K3EUI
Envoy¨¦ : mercredi 6 septembre 2023 13:59
|
Re: Nano VNA of a modified 40m hor loop NVIS antenna
I put in a CLC tuner in my shack, Please wat is a "CLC tuner" ? -- F1AMM Fran?ois -----Message d'origine----- De la part de Barry K3EUI Envoy¨¦ : mercredi 6 septembre 2023 13:59
|
Re: Nano VNA of a modified 40m hor loop NVIS antenna
JJ Night
To answer your question¡
There is nothing special about this antenna, other than it is a closed LOOP of 140 ft heavy wire #10 because I had a few hundred feet of this wire.
I wanted good daytime NVIS antenna for prop of only a few hundred miles from Phila around 10AM to 2 PM.
I was not interested in a low-angle DX signal for evening use (I have a vertical that does that well)
The amount of wire did not matter too much (120-140 ft to start).
I feed this with about 75 ft of RG213 (nothing special)
The shape is a rectangle, only 20 ft or so above ground. I had a few big strong trees as tie points.
I tried a 4:1 balun at first (thinking impedance of 100 ohms) and that did not work well.
I replaced that with a simple 1:1 BALUN (choke).
At the low height above ground, I expected a lower impedance than putting it up 50 ft.
I could attach the Nano VNA right at the feedpoint - direct - to avoid the feedline messing with impedance.
I then hooked it up to a CLC Tuner (in my shack) in case the SWR was high at the digi part of the band.
Because I had about 140 ft wire in the loop, the resonant point was just below 7 MHz (about 6.8 MHz).
It worked fine for two weeks, but then I thought maybe I could improve it by shortening it.
I pruned it back about 10 feet (harder to do for me on a 90 degree day) and then I saw that the minimum SWR fell around 7.1 MHz, right where I wanted it.
The NANO VNA that I own is already 3 years old (Amazon model) and I¡¯m using NANO VNA SAVER app on a Win10 (10 yr old) desktop. I had to make the CALIB first with a 3-30 MHz span at a 10x mag. That took a few minutes to do the OPEN, SHORT, and 50 0hm LOAD with the standards that came with the rig.
I did a sweep from 3-30 MHz using the 50 ohm standard and everything looked perfect on the 6 graphs.
That was reassuring!
The closed loop works far better than a pair of Hamsticks mounted horizontally (14 ft total). Well, obviously!
It works just about as well as a simple 66 ft Inverted V center-fed dipole (my standard) but I see much less QSB on the closed loop than from the dipole. I like to use 7047 kHz W1AW CW bulletins as my standard to compare antennas at 9AM to 10AM. And¡ it helps me copy CW by ear.
So nothing special about anything that I did.
I put in a CLC tuner in my shack, and this does sharpen up all of the graphs, but I did not really need it.
My goal: see if I could build a better DAYTIME NVIS antenna for low part of the 40m band.
I love the sound card digi modes and FLDIGI and am working on a new 40m EMCOMM digi mode net which should begin on October 1st: Mid-Atlantic 40m NBEMS net (7068 kHz vfo).
We plan to run this net every Sunday at 10AM to 11AM for a few months to see how well ¡°fickle forty¡± does at that hour with THOR22 (checkin) and THOR56 (traffic). We know that 80m collapses by 10 AM for NVIS.
I really did not need a Nano VNA to build and test this antenna. I am now doing A/B tests to see if folks I work on 40m digi modes can hear any differences between the closed loop and Inverted V simple dipole.
I took the back-to-back Hamsticks down (may be good for a portable setup)
And I still have a 36 ft vertical with two above ground radials (upside down T) for evening DX.
What are you trying to accomplish in your antenna?
Without the SAVER software, I¡¯d be lost (color blind).
de k3eui Barry
near Philly
Sept 06 2023
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Re: NanoVNA-APP chart options question
Hi Mark, Roger,
For NanoVNA-App (DiSlord version) these informations are calculated, but not plotted.
They are displayed on the Info Panel (info button must be turned on), right side at the lower part. Compared to my Libre Office calculation sheet, values are perfectly relevant.
73 Jean-Roger
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Re: Nano VNA of a modified 40m hor loop NVIS antenna
You can¡¯t go wrong with a loop. Would you walk me through how you went about testing it and tuning it? I have to build a new one myself and I¡¯m curious how you connected it to your vna. JJ Knight N5MNX ________________________________ From: [email protected] < [email protected]> on behalf of Barry K3EUI <k3euibarry@...> Sent: Tuesday, September 5, 2023 2:26:28 PM To: [email protected] < [email protected]> Subject: [nanovna-users] Nano VNA of a modified 40m hor loop NVIS antenna How are folks doing on a 40m NVIS antenna for daytime short-range COMS? A bit more tweaking of my 40m closed LOOP NVIS antenna for 7075 kHz Less than 1.5:1 SWR across 40m band Over 50dB return loss at resonant frequency 7075 kHz The Nano VNA graphs make this loop antenna easy to "tune up" I'm ready to try it out: 7068 kHz Sunday at 10 AM EDT with THOR 22 This antenna is about 2-3 S-units (15dB) stronger than back-to-back 40m 7 ft Hamsticks and also a few S-units stronger than my 40m vertical (34 ft lashed to a tree) on daytime coms de k3eui
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Re: Not available at Ali Express / Zeenko
Anyone with basic IT expertise will tell you the same. On Tue, 5 Sept 2023 at 17:16, Julio VE3FH via groups.io <ve3fh@...> wrote:
No, none of my computers and other devices has been compromised.
I will make no further comments on this pointless exchange because it has veered way off topic for the reflector plus you are dead set on exonerating PayPal and any other "reputable" payment processors of any responsibility.
73,Julio VE3FH
On Thursday, August 31, 2023 at 09:02:22 p.m. EDT, Dragan Milivojevic <d.milivojevic@...> wrote:
Your computer was compromised, nothing to do with Ebay or Paypal.
On Fri, 1 Sept 2023 at 01:25, Julio VE3FH via groups.io
<ve3fh@...> wrote:
No, I totally disagree with your statement. Based on personal experience, every time I had a credit card compromised it was shortly after either some eBay order or some PayPal payment processing. Last year when I called the bank to report a fraudulent transaction the first thing they asked me was if I had used the card on PayPal adding that several customers reported similar transactions that day with the commonality being PayPal.
I actually I have a second credit card that I use to pay for gas, groceries, etc. and never use online, guess what? that one never got hacked.
I agree with you though that there's no such thing as free shipping, the reality is that S&H is included in the price but no merchant is going to advertise that way, that's just a marketing tactic.
73,Julio VE3FH
On Wednesday, August 30, 2023 at 06:05:16 p.m. EDT, Dragan Milivojevic <d.milivojevic@...> wrote:
You have a million times greater chance of your card details getting
stolen when paying for gas than
the same happening when using PayPal.
On Wed, 30 Aug 2023 at 23:00, Julio VE3FH via i
<ve3fh@...> wrote:
I share your concerns. I bought my TinySA from the SeeSii store in ebay.ca, it and arrived in six days and shipping was USD $2.99, they do carry the NanoVNA H4 and I'll probably buy a NanoVNA from them shortly. The issue with ebay is that payments are processed by paypal so you risk your credit card being compromised, it happened to me at least three times already.
73,Julio VE3FH
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Re: NanoVNA-APP chart options question
On Tue, Sep 5, 2023 at 10:24 AM, Mark KQ4EKK wrote:
Is there a way to select those 5 options in NanoVNA-APP?
|S21|
S21 |Z| shunt
S21 |Z| series
S21 R+jX shunt
S21 R+jX series
NanoVNA app does not calculate/plot S21 impedance measurements. BTW S21 impedance measurements are not very accurate using NanoVNA's because they do not do 12 point error calibration and do not have precise 50 ohm source and termination impedances. You also need a good test jig or stray capacitance will greatly affect the measurements. If you search the archives of this group you will find many discussion posts on this topic. Using a -H4 I have found that i can make fairly good measurements from 2 to 3000 ohms impedance using the s11 shunt method. Roger
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Re: Not available at Ali Express / Zeenko
ae1th@, you mention this is the case with gift cards... I can see that as being a policy. Gift cards, while being great options, they have no real tracking ability especially on the internet. Many scammers out there are stealing money from people with fake IRS or whatever scams and are asking for payment in the form of gift cards. Some unsuspecting people and many of them being people that usually cant afford to lose money, fall for this scams and pay. And then there are the straight credit card frauds or theaves that go to stores and buy gift cards to convert it quickly and then use the gift card or sell the gift cards. Paypal caught onto this and probably made it a policy to not use gift cards. People can also quickly convert the gift cards to bitcoin via paypal payments and then they are clean and completely anonymous when purchasing. So, no more paypal as a gateway.... Price we need to pay for those that are bad out there.
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Barry K3EUI
Roger Need
