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Re: NanoVNA Saver software version 0.2.1 TDR operation
Rune,
Yes something is not quite right. I used the TDR function on the NanoVNA in stand-alone mode and got impedance measurements that made sense to me. I cascaded some 50 ohm (RG58), 75 ohm (RG59) and 93 ohm (RG62) coax and could see the impedance steps. |
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Re: Quality of shipped cables with NanoVNA-H
#measurement
#calibration
Herb,
Thanks for the info. Nice to know the source of the cable. Hope the connectors are properly installed. Roger |
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Re: First PCB pictures of the V2
option to rotate screen 180 degrees: should be doable; I think the ILI9341 has a command to do that without flipping the data.
bluetooth: not yet, maybe V3 ;) display size: base version will have a 2.8'' display. User can swap in a 3.2'' ILI9341 display (drop in replacement) or a 4'' ST7796S display (pending firmware support). We are likely going to offer a version with 4'' display, maybe a month or so after the release of the base version. jog switch: it's already the same part number as the one used in the -F, just without the nipple installed. Using the jog switch is optional as all features can be accessed from the touch screen. price: most likely similar to the -H, so around $60. I don't know where the $100 BOM cost rumor comes from but it's false, the BOM cost can't be anywhere near $100 if this is to retail for $60 ;) There aren't much development costs because OwOComm sponsored the initial R&D on condition that all designs be open sourced. I've attached the uncalibrated load plot. The performance of the baluns deteriorate rapidly above 3GHz so this is going to be marketed as a 3GHz instrument rather than a 3.5GHz one. On this particular unit the nastiness starts at 3.4GHz. |
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Re: Cases
Hope the keyboard lived through the experience ;)
I'm interested in a case as well. Cheers, Lyle NM6Y On Wed, 18 Dec 2019 06:19:40 +0000 "Les Brown" <les.m0lpb@...> wrote: Sorry, had to run and the keyboard hit the floor.-- 73 NM6Y Bickley Consulting West Inc. "Black holes are where God is dividing by zero" -- 73? ?NM6Y Bickley Consulting West Inc. "Black holes are where God is dividing by zero" |
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Re: errors of "error" models
REF: 17 December 2019 - /g/nanovna-users/message/8335
- Dear Gary: this is obviously another experiment by itself - the objective is to investigate the possibility of an openly edited paper - at least one - and the paper by itself constitutes a concrete knowledge target - needless to say how much interesting we find this scientific procedure - best regards, gin&pez@arg - ps: let us know, please, if it is easy enough for you to get the basic paper by Hackborn from a nearby Library - |
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Re: Cases
Thanks Paul for your message, I will add you to the list and put a note on the group when I am ready in Jan. 2020.
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We can only but try. 73 ¨C All the best for the holidays to you and your family, talk in the new year. Les ¨C M0LPB Sent from Mail ( ) for Windows 10 *From:* Paul Sayer ( paulsayer123@... ) *Sent:* 18 December 2019 11:18 *To:* [email protected] *Subject:* Re: [nanovna-users] Cases I would be interested as well. Paul G0VKT On Wed, 18 Dec 2019, 10:12 Les Brown, <les.m0lpb@...> wrote:
Hi, As soon as we have a case for testing, I will put the information up on the group. Thanks for your reply, it is good to know that there is interest out there for the case. 73, all the best for the holidays, talk in the 2020 Les ¨C M0LPB Sent from Mail ( ) for Windows 10 *From:* davebb123456 via Groups.Io ( david.browne7@... ) *Sent:* 18 December 2019 07:06 *To:* [email protected] *Subject:* Re: [nanovna-users] Cases Hi Les I would like a case, let me know when you get some done, Thanks Dave Browne 2E0DMB On 18 Dec 2019 6:19 am, Les Brown <les.m0lpb@...> wrote: Sorry, had to run and the keyboard hit the floor. I have downloaded a basic design, and we can mod it as we like. But as I keep saying, the cost will be min. For all Ham radio Lic. Holders. 73 Les M0LPB Sent from Mail ( ) for Windows 10 *From:* Les Brown ( lesdbrown@... ) *Sent:* 18 December 2019 05:20 *To:* [email protected] *Subject:* Re: [nanovna-users] Cases Hi, All I have downloaded a basic design, this is eh1111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111llllllllllllllllllllllllllllllllllllllllllllllllllllllllsssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss Hi, All I have downloaded the basic design from this link:- This design looks OK, but I need to put it up on to the 3D printer to find out if any problems. Regards Price - this will be base of our case and if any mods needed, we can look at it from there. All cases made by me from home, will be at cost of material plus P&P were needed, and that is it to all Ham Radio Lic. holders. It might not be good business, but I am not in to making money from friends. Yours Les - M0LPB |
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Thermal effect?
Recently, I measured a 30 m loading coil for a short vertical antenna with my NanoVNA. I powered the VNA, calibrated for a span from 9 MHz zu 11 MHz with Nano VNA Saver 0.2.0 and started measuring (average 9/4) S11 (R+jX and Q). Repeating the scan, I found R slightly higher, but X beeing the same as before. So I measured again, with the same effect: R drifts higher, X stays the same.
Continually running scans, a pattern evolved. Checking the attached figure, it is clearly observable that R increased for about half an hour before the measured value stabilizes. X however is stable, right from the beginning. I stopped the scans after 37 minutes, when I had the feeling that it leveled out. After re-calibrating I measured again. It came as no surprise, that the NanoVNA continued to measure the same number for X. However, R was down (even a touch lower) to the value which I measured at the very beginning. But now it stayed at that number. My conclusion is, that there is a thermal effect during the warming up of the NanoVNA. Once the device has operating temperature this drift disappears. For whatever reason this seems to effect low |Z| (in my case around 1 Ohm for the real part of the impedance) to a much higher degree than higher values. I assume, this effect is lowest for |Z| around 50 Ohm. If you are aiming for high precision, especially at low |Z|, my advise is to let the NanoVNA warm up for about half an hour, and only than calibrate and start to measure. Has anybody encountered anything similar? Vy 73, Chris, OE1CGS |
Roger Need
OwO
Lyle Bickley
Juan Pablo EA4CIV
gin&pez@arg
Les Brown
