On 8/13/23 2:41 PM, Brian Beezley wrote: Thanks, Roger. I've seen plenty of NanoVNA App plots here, but none with phase unwrapped.
Brian
Maybe because nobody bothered to try? <grin> Sometimes, I find the derivative of unwrapped phase (group delay) more useful, too.
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Re: Nano VNA SAVER graphs of a 40m loop antenna
I have a 40m 144' horizontal loop also at about 20'. It is a right triangle. The pointy end is due east and is a little lower. I feed it with BalunDesigns 1:1 balun and then about 55 feet of 450-ohm line . My MFJ-939 or my AT-250 can tune it up on 40m-6m, and the MFJ will even tune it up on 80m. I have worked 115 countries and 50 states on FT8 across various bands in about 7 months, including DX on 40m and even 80m. So I would not say a low loop is NVIS only :) .
Nevertheless, Barry, could you describe your 40' vertical that you say is much better for low-angle DX?
For obligatory NanoVNA content, I will say that the NanoVNA was invaluable in picking the right feedline length. The length is quite touchy, and I did a lot of adding and removing short lengths to find what worked on all bands. The last length is a 3-foot jumper which I sometimes remove for best tuning.
Dan, KB1RT
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I like my SAA-2N, it is the one I generally reach for in the shack. It works fine with external programs or standalone, updates work fine, and I like the type N connectors, as my shack is mostly type N. The provided cables and calibration standards appear to be of high quality and performance. Got mine from R&L. Highly recommended and I have been using VNAs since the '70s and am pretty picky about instruments.
73, Don N2VGU
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I don't see much mention of the SAA-2N v2.2 Does everyone recommend the H4 over the SAA-2N?
The price difference is not of concern I am more concerned about functionality and support.
Brian
W1BKW
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What ever you buy, I'd recommend using its "official shop". There are links on the homepage.
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I would strongly recommend buying from R&L Electronics. You won't get a
clone from them!! Here is the link to them for the NANOVNA-H4:
No connection to them other than having bought a number of NANOVNAs (too
many as they progressed) and TinySAs from them.
Dave - W?LEV
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On Tue, Aug 15, 2023 at 8:01?PM Stan Dye <standye@...> wrote: Nanovna-H4 is a great basic vna, if you don't need multiple GHz
frequencies. It runs the latest firmware and is actively supported. And
you should be able to get one for less than $100
On Tue, Aug 15, 2023, 11:20 AM Leif M <leif.michaelsson@...> wrote:
Have you checked the homepage(s). Like and
I can recommend V2 Plus4 Pro V2.4, it costs 299$ plus 18650 battery. But
today I would try to buy pro version at 399.
There are several Group IO forum for VNAs. For instance
/g/NanoVNAV2/topics
-- *Dave - W?LEV*
--
Dave - W?LEV
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Nanovna-H4 is a great basic vna, if you don't need multiple GHz
frequencies. It runs the latest firmware and is actively supported. And
you should be able to get one for less than $100
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On Tue, Aug 15, 2023, 11:20 AM Leif M <leif.michaelsson@...> wrote: Have you checked the homepage(s). Like and
I can recommend V2 Plus4 Pro V2.4, it costs 299$ plus 18650 battery. But
today I would try to buy pro version at 399.
There are several Group IO forum for VNAs. For instance
/g/NanoVNAV2/topics
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Re: Nano VNA SAVER graphs of a 40m loop antenna
Hi Jim.
Thanks for the reply. The answer is simple. Convenient! A pair of trees are there, about 100 feet apart and between them, nothing.
No balun used. The ends of the dipole are away from each tree by at least 20 feet. So its pretty much floating in space except close
to ground.
The ground is clay and can be damp at times. I cut the wire lengths wrong the first time and swr at 7050 was way off. Remeasured
and sure enough I was off by more than 10 feet! Cut a pair of 5 foot wires, twisted them in place, done. Hung the vna in the air with a
couple of gator clips, done. Coax back to the shack.
Although NEC says this is a zenith burner, there is still reasonable gain at say 45 degrees off horizon.
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Have you checked the homepage(s). Like and I can recommend V2 Plus4 Pro V2.4, it costs 299$ plus 18650 battery. But today I would try to buy pro version at 399. There are several Group IO forum for VNAs. For instance /g/NanoVNAV2/topics
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Re: Nano VNA SAVER graphs of a 40m loop antenna
Hello Alan
Did you start with some ideal calculated length for 7.05 MHz, set the dipole at 7 feet high and then trim the length for best return loss? Or perhaps put up precut wire for a higher frequency and upon measuring found that 7.05 was the best match?
Do you have good soil conductivity? (Not dry, Rocky, Sandy soil?)
You are most likely operating NVIS but I¡¯m curious as to how you arrived at that configuration.
Jim
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I know this is old but thank you so much for posting that link about the larger screen job. That guy did an amazing job and it was enjoyable to scroll through Good day !
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I am doing something wrong. I uploaded bin file of memory to my computer (NanoVNA.H.v1.1.00FromVanoVNA.bin). If I compare what I saved to my computer to memory, I get a match. I then downlodaed from dislord what I think is my firmware (NanoVNA.H.v1.1.00.dfu). I used dfuse_extract.py to convert to bin (NanoVNA.H.v1.1.00.bin). If I compare what I think is my FW (converted to bin) to memory, no match. The converted bin is 95KB. What I extract from memory is 1KB. I am not too concerned about the download (DFU) and converted (BIN) not matching. It may not be correct FW. What does concern me is the size mismatch. Something does not add up.
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NanoVNA-H4
NanoVNA v2 Plus4
Istvaan
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Re: Is a negative Offset Delay in ps ok?
Hi Stan and others,
Thanks for the reply. Based upon my photos from earlier in the thread does a negative offset delay seem reasonable. It doesn't to me, but my experience is limited.
Best,
Chris
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Hi,
I like to replace my first edition NanoVNA with a newer, read better one.
Can you advise me a good model that runs with the Nanovna-saver program and does not break the bank?
73' Ron
ON2RON
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Re: Is a negative Offset Delay in ps ok?
Normally you try to calibrate at the reference plane where you want to take the measurements, and the delay is set to 0.
The e-delay is a method of adjusting the position of the reference plane before making a measurement, and could be positive or negative - but the most common use is positive.
If you have an additional known length of cable/connector between your calibration point and the device you want to measure, you would enter a positive delay to represent that additional length.
If you calibrate and then remove a piece of cable, making the measurement plane closer than your calibration, then you can put in a negative delay to compensate for that length of cable that is not there anymore.
Note that e-delay does not do a perfect translation of the reference plane: it only compensates for time (i.e. phase and delay), not other impairments like loss in the cable. So calibration at the measurement point is preferred, especially for longer cables that could be lossy at the measurement frequencies.
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Re: Is a negative Offset Delay in ps ok?
Hello Robin.
Thanks for the response. The F-F adapter 15mm long. It was replaced with about 50mm of transmission line in the form of a female SMA with 50 ohm coax cable. My question is about using a negative value for the offset delay. +200ps looks terrible on the Smith chart, worse than no delay, whereas -205 creates a fairly tight cluster of points across the swept frequency. I'm fairly new to NanoVNAs and the NanoVNA Saver Windows app but all the articles and comments I read on Offset Delays are using positive values which to me imply compensating for a longer cable than what was calibrated. Is my head in vacuum?
Chris
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Re: Is a negative Offset Delay in ps ok?
Christopher,
in air¡ªstrictly vacuum¡ª205 ps is equivalent to about 60 mm, which is not so far off the length of the F-F adapter that you had removed.
The numbers, when all is going well, tend not to lie.
HTH, 73,
Robin, G8DQX
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On 15/08/2023 00:45, Christopher Dundorf wrote: Hello,
I SOL calibrated my NanoVNA using a 30cm cable + F to F SMA coupler and the SOL end pieces. I removed the coupler and attached the 30cm cable to a ~5cm 50 ohm coax cable soldered to the input of a matching network which goes to a 900MHz Igneon PCB antenna. When using the tip of a knife to short the soldered-on end of the coax cable I need to use -205ps offset delay to bring the majority of the points to the left edge of the Smith Chart. Positive values make the plot worse. Is it ok to use a negative number with the NanoVNA Saver? That seems counter intuitive.
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On Mon, Aug 14, 2023 at 04:44 AM, Stefan Dimitrov wrote: The situation is:
None on com ports menu and no any list.
The next menu:
"Disconnected"
Looks like no com ports or Windows 10 can't see the program. You need to use Device manager to see if a COM port is active for your NanoVNA. If it isn't there you need to get it installed somehow. The method depends on which OS you are using. Once you can select the correct COM port click the Disconnected button and you should be good to go... Try reading the Absolute Beginners Guide in the files section of this group. Roger
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Is a negative Offset Delay in ps ok?
Hello,
I SOL calibrated my NanoVNA using a 30cm cable + F to F SMA coupler and the SOL end pieces. I removed the coupler and attached the 30cm cable to a ~5cm 50 ohm coax cable soldered to the input of a matching network which goes to a 900MHz Igneon PCB antenna. When using the tip of a knife to short the soldered-on end of the coax cable I need to use -205ps offset delay to bring the majority of the points to the left edge of the Smith Chart. Positive values make the plot worse. Is it ok to use a negative number with the NanoVNA Saver? That seems counter intuitive.
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Donald S Brant Jr
Brian Wall
Roger Need
