Re: v5.3 won't start after v6.2 crashed
On Tue, Aug 8, 2023 at 08:06 AM, WY6K Mike Watts wrote:
Even though I have rebooted several times NanoVNA-Saver will not start. The
DOS window opens but then it does nothing. It seems to me that v6.2 broke
something that v5.3 needs to run. Maybe python? I don't know what to do to
get it going again....
You have a corrupted NanoVNA-Saver ini file which contains all the settings parameters. You have to do a file search for this file ----> NanoVNASaver.ini and then delete it. Then try running Saver again and it should now work for you. Roger
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Re: v5.3 won't start after v6.2 crashed
Under windows?
Do you use the exe file?
For the exe, you don't need python installed.
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Re: v5.3 won't start after v6.2 crashed
Did you wait a very long time? Like 4 or 5 minutes after the dos window appears? Sometimes it takes a very long time for python to get everything started up after a change. On Tue, Aug 8, 2023, 8:06 AM WY6K Mike Watts via groups.io <wy6k= [email protected]> wrote: Even though I have rebooted several times NanoVNA-Saver will not start.
The DOS window opens but then it does nothing. It seems to me that v6.2
broke something that v5.3 needs to run. Maybe python? I don't know what
to do to get it going again....
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Re: Best Way to Measure Antenna SWR
I would think you would want to know exactly where the antenna stood before complicating matters by assuming the antenna is ok and your not knowing where your hi swr readings are coming from. Fred N4CLA On Mon, Aug 7, 2023 at 10:58?AM John Baines via groups.io <jbaines= [email protected]> wrote: Peter,
It depends what you want.
Measuring at the antenna allows you to check the resonant frequency and
the complex impedance of the antenna (to design a match to the coax
impedance - often 50 ohms)
Measuring at the indoor end of the coax lets you see the complex impedance
of the antenna plus coax system to determine whether a tuning unit is
needed.
73
John
M0JBA
On 7 Aug 2023, at 15:47, Peter N0PGM <pgmelton@...> wrote:
Hello,
Once my antenna is up it will have a 50ft run of coax that enters my home. Do I measure the swr at the base of the antenna (before the 50ft of
coax) or inside the house (at the end of the coax)?
Thanks in advacne,
Peter
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v5.3 won't start after v6.2 crashed
Even though I have rebooted several times NanoVNA-Saver will not start. The DOS window opens but then it does nothing. It seems to me that v6.2 broke something that v5.3 needs to run. Maybe python? I don't know what to do to get it going again....
|
Re: Best Way to Measure Antenna SWR
Cable loss to antenna will reduce the forward, then return reflected power.
It can be calibrated out but the round trip loss reduces the dynamic range of network analyzer by the round trip dB loss. If you are looking to get impedance at the antenna you must calibrate out the cable because you also need the phase information correct for network analyzer to figure terminal impedance at end of cable.
Also on NanoVNA, when measuring antennas you have to be careful of strong nearby radio transmitters, like AM or FM broadcast stations. The input mixer chip of NanoVNA can be overloaded by strong RF signals.
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Francesco, I purchased mine from a vendor on E-Bay in China. My F-V2 had just died and was thinking about buying a replacement. I had already seen reviews of this model and decided to give it a go. I was shocked that I received mine in about 10 days. It arrived in near perfect condition.
The firmware is pretty good but not 100% stable. I'm seeing some strange issues with reading when doing tight calibrations. For example, if I calibrate from 700-1100 meg and run a simple SWR sweep then the device gets into a weird state. I have to reset the calibration and load a known-working save file.
The functionality is really nice. The large screen is amazing and makes it really fun to use. It is very hefty however. If you want something that's pocketable then this definitely is NOT the device for you. It's large and heavy.
There are some UI issues that I don't like but they are workarounds for them. You can easily touch-drag markers anywhere on the screen if they get in the way, etc.
I hope the firmware becomes more stable in the short term. I'm debating about buying another F-V2 in the mean time for something pocketable. The firmware on the V2 was near perfect, at least for my needs.
-Nick, k7cj
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Re: Best Way to Measure Antenna SWR
NOPE!? ? Due to coax losses, the analyzer doesn't see the reflected power.
SWR is LOWER with a long coax.
Assuming the coax is not damaged of course.
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On Monday, August 7, 2023 at 02:34:59 PM CDT, Dave via groups.io <dvfuller@...> wrote:
I think that's what Roger was trying to say. The SWR at the antenna will be higher because of losses to the return signal back at the receiver.
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Re: Best Way to Measure Antenna SWR
/The SWR at the transmitter will be higher at the antenna than at the receiver.///
Shouldn't the SWR be lower, because at the transmitter, power reflected from the antenna will be attenuated by losses in the transmission line?
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On 8/7/23 11:35, Roger Need via groups.io wrote: On Mon, Aug 7, 2023 at 07:47 AM, Peter N0PGM wrote:
Once my antenna is up it will have a 50ft run of coax that enters my home. Do
I measure the swr at the base of the antenna (before the 50ft of coax) or
inside the house (at the end of the coax)?
The SWR at the transmitter will be higher at the antenna than at the receiver. The more attenuation in the transmission line the greater the difference. See attached graph below.
Roger
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Re: Best Way to Measure Antenna SWR
On Mon, Aug 7, 2023 at 07:47 AM, Peter N0PGM wrote: Once my antenna is up it will have a 50ft run of coax that enters my home. Do
I measure the swr at the base of the antenna (before the 50ft of coax) or
inside the house (at the end of the coax)?
The SWR at the transmitter will be higher at the antenna than at the receiver. The more attenuation in the transmission line the greater the difference. See attached graph below. Roger
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Re: Best Way to Measure Antenna SWR
Coaxial cables have loss. With long cables it is best to match the antenna to 50 ohms before connecting it to the cable. If this is not done, a mismatch between the cable impedance and the antenna reflects some power back to the transmitter. The cable loss dissipates some of the reflected power and less of it is reaches the transmitter than was actually pushed back by the antenna. If the cable is mismatched at both the antenna and transmitter ends, then part of the power reflected by the antenna travels back and forth between mismatches creating further losses in the cable. Power lost in the cable does not get radiated and does not show up as bad VSWR at the transmitter end giving the false impression of a better match than is actually present. __Joe VE6JSL On Mon, Aug 7, 2023 at 09:06 Zack Widup <w9sz.zack@...> wrote: I generally measure it at the end of the coax in the shack. That way I see
what the rig is going to see. I have had really long stretches of coax to
the antenna and the NanoVNA was unable to measure the SWR. I think it
required more power to overcome cable losses. In that case I had to check
it with a lot shorter length of coax.
73, Zack W9SZ
On Mon, Aug 7, 2023 at 9:47?AM Peter N0PGM <pgmelton@...> wrote:
Hello,
Once my antenna is up it will have a 50ft run of coax that enters my home.
Do I measure the swr at the base of the antenna (before the 50ft of coax)
or inside the house (at the end of the coax)?
Thanks in advacne,
Peter
-- __Joe Leizerowicz 6424 34 Avenue NW, Calgary, AB T3B 1N1 403-604-7791
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Re: Best Way to Measure Antenna SWR
I really don't know. I just didn't seem to be getting a signal back through
the coax for some reason. My RigExpert AA-600 did OK in measuring the SWR
on the same coax and antennas, though. This was all on the HF ham bands -
3.5, 7, 14, 21 and 28 MHz. I don't know of any really strong signals on HF
that might cause that.
73, Zack W9SZ
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On Mon, Aug 7, 2023 at 12:17?PM W0LEV <davearea51a@...> wrote: I'd propose the lack of ability to measure SWR is not due to the long coax,
but due to strong local sources of RF.
Dave - W?LEV
On Mon, Aug 7, 2023 at 3:06?PM Zack Widup <w9sz.zack@...> wrote:
I generally measure it at the end of the coax in the shack. That way I see
what the rig is going to see. I have had really long stretches of coax to
the antenna and the NanoVNA was unable to measure the SWR. I think it
required more power to overcome cable losses. In that case I had to check
it with a lot shorter length of coax.
73, Zack W9SZ
On Mon, Aug 7, 2023 at 9:47?AM Peter N0PGM <pgmelton@...> wrote:
Hello,
Once my antenna is up it will have a 50ft run of coax that enters my home.
Do I measure the swr at the base of the antenna (before the 50ft of coax)
or inside the house (at the end of the coax)?
Thanks in advacne,
Peter
--
*Dave - W?LEV*
--
Dave - W?LEV
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Re: Best Way to Measure Antenna SWR
I'd propose the lack of ability to measure SWR is not due to the long coax,
but due to strong local sources of RF.
Dave - W?LEV
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On Mon, Aug 7, 2023 at 3:06?PM Zack Widup <w9sz.zack@...> wrote: I generally measure it at the end of the coax in the shack. That way I see
what the rig is going to see. I have had really long stretches of coax to
the antenna and the NanoVNA was unable to measure the SWR. I think it
required more power to overcome cable losses. In that case I had to check
it with a lot shorter length of coax.
73, Zack W9SZ
On Mon, Aug 7, 2023 at 9:47?AM Peter N0PGM <pgmelton@...> wrote:
Hello,
Once my antenna is up it will have a 50ft run of coax that enters my home.
Do I measure the swr at the base of the antenna (before the 50ft of coax)
or inside the house (at the end of the coax)?
Thanks in advacne,
Peter
-- *Dave - W?LEV*
--
Dave - W?LEV
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I think we should all consider that the Discone is actually and improved
version of rhe Biconical dipole and not the other way around.
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On Mon, Aug 7, 2023, 8:53 AM K8HTB <k8htb@...> wrote: If you are connected to a pc I put a clamp on ferrite on the usb cable.
Also have to be careful if you are holding the vna as you become part of
the antenna.
I made a large metal ground plane fixture and calibrate the cable
connected to it about 15 feet away from the whips I test. Usually having
two different readings is an indication of coupling isolation issues.
K8HTB Joe
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Re: Best Way to Measure Antenna SWR
Measure it BOTH times.
First to make sure the antenna is properly tuned while it is still easy to work on.
Second on the tower to make sure the coax fittings and the coax line are good.Kent WA5VJB
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On Monday, August 7, 2023 at 09:47:24 AM CDT, Peter N0PGM <pgmelton@...> wrote:
Hello,
Once my antenna is up it will have a 50ft run of coax that enters my home. Do I measure the swr at the base of the antenna (before the 50ft of coax) or inside the house (at the end of the coax)?
Thanks in advacne,
Peter
|
Re: Best Way to Measure Antenna SWR
I generally measure it at the end of the coax in the shack. That way I see
what the rig is going to see. I have had really long stretches of coax to
the antenna and the NanoVNA was unable to measure the SWR. I think it
required more power to overcome cable losses. In that case I had to check
it with a lot shorter length of coax.
73, Zack W9SZ
toggle quoted message
Show quoted text
On Mon, Aug 7, 2023 at 9:47?AM Peter N0PGM <pgmelton@...> wrote: Hello,
Once my antenna is up it will have a 50ft run of coax that enters my home.
Do I measure the swr at the base of the antenna (before the 50ft of coax)
or inside the house (at the end of the coax)?
Thanks in advacne,
Peter
|
Re: Best Way to Measure Antenna SWR
Peter,
It depends what you want.
Measuring at the antenna allows you to check the resonant frequency and the complex impedance of the antenna (to design a match to the coax impedance - often 50 ohms)
Measuring at the indoor end of the coax lets you see the complex impedance of the antenna plus coax system to determine whether a tuning unit is needed.
73
John
M0JBA
toggle quoted message
Show quoted text
On 7 Aug 2023, at 15:47, Peter N0PGM <pgmelton@...> wrote:
Hello,
Once my antenna is up it will have a 50ft run of coax that enters my home. Do I measure the swr at the base of the antenna (before the 50ft of coax) or inside the house (at the end of the coax)?
Thanks in advacne,
Peter
|
Best Way to Measure Antenna SWR
Hello,
Once my antenna is up it will have a 50ft run of coax that enters my home. Do I measure the swr at the base of the antenna (before the 50ft of coax) or inside the house (at the end of the coax)?
Thanks in advacne,
Peter
|
Thanks for all the great advise. I really appreciate it. I'm still in the process of ordering everthing I need to install my antenna. It involves drilling holes in exterior wall, installing interior and exterior boxes and ground cables and putting up the antenna.
I'll be able to ground the antenna cable with the ground I am bringing into the house.
Thanks again,
Peter
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If you are connected to a pc I put a clamp on ferrite on the usb cable. Also have to be careful if you are holding the vna as you become part of the antenna.
I made a large metal ground plane fixture and calibrate the cable connected to it about 15 feet away from the whips I test. Usually having two different readings is an indication of coupling isolation issues.
K8HTB Joe
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Roger Need
WY6K Mike Watts
Paul - AI7JR
Peter N0PGM #3460