That is the kind of confirmation I was looking for, thanks Ismo! Between that and the fact that R&L is out of stock on the H4 right now, makes me feel good about getting the SAA2N instead.
Again, Thanks, Ismo!
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On Wed, Feb 3, 2021 at 08:10 AM, Ismo V??n?nen OH2FTG wrote:
From what I understand SAA2N has better dynamic range than the 1.5GHz nanoVNA
and thus is better for duplexer and cavity filter tuning.
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Re: backyard antenna ranges
Jim,
Nice idea. I had been thinking of this myself. I am working on a discone antenna and given it's wide-band and omnidirectional response thought that it would serve well as a receiving antenna for measuring antenna pattern and gain. I'll be sure to let the group know how it works out.
Mark Walter
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When looking at the front end of the nanovna you see a 10?F capacitor in series with the MXD8641¨CSP4T Switch. This switch can resist 100V in electrostatic discharge sensitivity testing (Machine Model). This test is done with a loaded 200pF capacitor and a 0.5 ?H inductor in series.
A typical koaxcable (RG213 od RG58) with 100pF/m and 20m length will have 20nF of capacitance. If this koax is loaded to 200V by electrostatic, it will damage the MXD8641. Also if you measure an outdoor antenna and there is electrostatic in the air, you may damage your measuring equipment also.
It may be a good thing to protect your nanovna with ESD-diodes when measuring long koaxcables and/or outdoor antennas.
73, DK5DN
Am 04.02.2021 um 10:30 schrieb Stephen Laurence:
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Does this mean that a long length of coax can store/return dangerous (to the vna) voltages, for example like a Tesla coil, or was the coax connected to something at the other end?
Should we all be installing esd diodes to the port 1 input? Port 2 already has a 14db attenuator. Is there a limit to the length we can measure?
Steve L
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Re: How do I load DMR-CLEAR_MEMORY_DFU.dfu
On Wed, Feb 3, 2021 at 09:23 PM, John AE5X wrote:
All better now - I was expecting it to indicate that it was in DFU mode. No
indication of it, but it was. Thanks again,
--
John AE5X
Yes, manually putting it into DFU mode doesn't give you any indications except: - on the H and previous devices, the screen is white - on the H4, the screen stays dark If you search through my posts, there is a mod that places a jumper from the centre pin of the jog sw to the boot0 input. This lets you hold down the jog while turning the unit on - same as the H4. makes life easier. ...Larry
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Does this mean that a long length of coax can store/return dangerous (to the vna) voltages, for example like a Tesla coil, or was the coax connected to something at the other end?
Should we all be installing esd diodes to the port 1 input? Port 2 already has a 14db attenuator. Is there a limit to the length we can measure?
Steve L
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Sorry if my last message was lacking a little in context. The directions I was following were in the document mentioned earlier in this thread, nvna-s-pve-rev-d.pdf
¡ª Greg
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I've been trying to follow the directions given above to install nanovna-saver on my Linux Mint 20 system. It's a pretty standard installation; I haven't (knowingly) done anything unusual.
I've encountered issues:
python3.7 is no longer available in the standard repos; it's now python3.8 I followed the directions substituting 3.8 for 3.7
All seems to go well until Item 7, "7. Install the latest versions of pip, setuptools and wheel". In that section
(nvna-s) greg@greg-Mint1:~/.venv/nvna-s$ curl | python
produces:
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
100 1884k 100 1884k 0 0 8376k 0 --:--:-- --:--:-- --:--:-- 8376k
WARNING: pip is configured with locations that require TLS/SSL, however the ssl module in Python is not available.
WARNING: Retrying (Retry(total=4, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError("Can't connect to HTTPS URL because the SSL module is not available.")': /simple/pip/
... [Repeated a number of times] ...
Could not fetch URL There was a problem confirming the ssl certificate: HTTPSConnectionPool(host='pypi.org', port=443): Max retries exceeded with url: /simple/pip/ (Caused by SSLError("Can't connect to HTTPS URL because the SSL module is not available.")) - skipping
ERROR: Could not find a version that satisfies the requirement pip
ERROR: No matching distribution found for pip
I went back and installed python3-openssl, but continue to get the same error.
I'm a C programmer, but I confess I'm pretty ignorant about python, so I need some help!
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Re: How do I load DMR-CLEAR_MEMORY_DFU.dfu
All better now - I was expecting it to indicate that it was in DFU mode. No indication of it, but it was. Thanks again,
--
John AE5X
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Re: How do I load DMR-CLEAR_MEMORY_DFU.dfu
Nope, but tnx anyway. Gives me an excuse to buy the 4" version.
--
John AE5X
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Re: How do I load DMR-CLEAR_MEMORY_DFU.dfu
John, Just put the device into dfu mode by shorting the boot0 pins on the side (open the cover) and powering it up. Then, use defuse demo as always.? All of this is noted in various user guides...... On Wed., 3 Feb. 2021 at 7:19 p.m., John AE5X<ae5x@...> wrote: No joy. -- John AE5X
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Re: How do I load DMR-CLEAR_MEMORY_DFU.dfu
On Wed, Feb 3, 2021 at 04:19 PM, John AE5X wrote:
No joy.
If you can't get it into DFU mode on your -H4 (4 inch screen) by pushing the jog switch/power you might have to open the case and jumper the Boot pins to get it into DFU mode. I have not done this before. Maybe someone else will jump in and help. If you can get it into DFU mode I would just try reloading Hugen's last firmware release and see if that works. Roger
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Re: How do I load DMR-CLEAR_MEMORY_DFU.dfu
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Re: How do I load DMR-CLEAR_MEMORY_DFU.dfu
On Wed, Feb 3, 2021 at 02:39 PM, John AE5X wrote: I have the dreaded white screen after attempting a firmware update. Reading
past postings indicates that I need to load DMR-CLEAR_MEMORY_DFU.dfu
My PC no longer sees the vna, therefore "Available DFU Devices" in DfuSe is
blank and nothing can be selected. What step(s) am I missing?
Have you tried powering off and then holding down the jog wheel while you power on to go into DFU mode? If that works try loading your firmware release again (make sure it is for the H4) and see if that works. If it does I would do a clearconfig 1234, calibrate the touch screen and then save. Then do a a calibration and save to slot 0. Power off/on and make sure it all works with your different loads. Roger
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Re: NanoVNA RF Demo Kit connection
On Wed, Feb 3, 2021 at 08:52 PM, arnold slag wrote:
Same problem here!
Have a look in the wiki: /g/nanovna-users/wiki/1659273, Rudi DL5FA
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Re: How do I load DMR-CLEAR_MEMORY_DFU.dfu
Correction: nanoVNA-H
No "4"
--
John AE5X
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How do I load DMR-CLEAR_MEMORY_DFU.dfu
into a nanoVNA-4?
I have the dreaded white screen after attempting a firmware update. Reading past postings indicates that I need to load DMR-CLEAR_MEMORY_DFU.dfu
My PC no longer sees the vna, therefore "Available DFU Devices" in DfuSe is blank and nothing can be selected. What step(s) am I missing?
Tnx/73,
--
John AE5X
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Re: backyard antenna ranges
On 2/3/21 11:50 AM, Dave W6OQ wrote: "I've also found the same general idea very useful in measuring the relative coupling between my various ham antennas so that I can decide if I need to worry about protecting receivers on a given antenna from transmitters on others...."
That's a very usable idea! Thanks
Oddly, I was just about to measure the port to port isolation on a RCS-8V, to see if it's safe to leave the NanoVNA connected to one port, and the 100W transceiver to the other.? +50 dBm on one port, probably want to keep power on the other ports <0dBm, so we'll find out if the measurement floor is low enough for the measurement.
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Your long coax cable has destroyed input components (C1 or input switch MXD 8614) at connector 1 of your nanovna. This may happen due to electrostatics on the cable. You should shorten the cable bevor making measurements.
You can measure the input reflection of your defective nanovna with another vna. When the measured nanovna is off, you normaly measure an open. When you switch it on, then you should measure a 50 ohm at the input, but only for seconds. When the measured nanovna is energized with RF, then your measurement is disturbed by this RF.
73, DK5DN
Am 03.02.2021 um 20:06 schrieb Thomas Kerns:
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I have an SAA2N that has been working fine. Yesterday I was using it to measure a long run of coax, and it was working fine. Then it just started acting like it was not sending a signal out of port 0. I reset the calibration, and noticed on the smith chart with nothing attached to port 0, the dot was near the left side of the smith chart that would normally indicate a short. I put the 50 ohm load on it, and the dot did not move, nor when I put on the short.
I decided to calibrate it, so ran through the calibration procedure, and now I get the spaghetti screen (lines all over the place). If I reset the calibration, it goes back to the trace on the left side of the smith chart.
It is acting like there is a short on port 0. Has anybody had this happen? I tried resetting everything, and results are exactly the same...
Thoughts?
Thanks!
Tom
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Measuring HF balun Performance
I thought these might be of interest to the group.
Properly Testing Baluns by W8JI
Measuring HF Balun Performance by W6WO
Roger
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Re: NanoVNA RF Demo Kit connection
Same problem here!
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Op do 29 okt. 2020 14:20 schreef Richard <raitchd@...>: I have a new RF Demo Kit board that came with two connecting wires. One
end is an SMA male connector and the other end is something that I have
never seen before. It is supposed to connect to the test positions on
the circuit board. I have not been able to make the connection because
it is very resistant and may take a lot more force than I am willing to
do before I learn more about it. Any suggestions would be appreciated.
Richard KC9UB
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schweppe
Roger Need
