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38 : Update - The [LeastVNA] @Gary O'Neil - 6 October 2019 : /g/nanovna-users/message/4194 35 : Straight In The Heart of The Matter - 6 October 2019

Frequency stepping in the current firmware is done only with the SI5351 Early firmwares explicitly rounded the requested frequency to multiples of 100 making it impossible to do small steps The

Rudi, thank you very much! :-) -- Rune

Herb, thank you for the suggestion of a band stop mode! I have been aware of it, but I still need to figure out exactly how it should be done. It's on the list :-) -- Rune / 5Q5R

Thank you for the data, Bryan :-) It's a great help. -- Rune [email protected]> wrote:

The hardware differences between the commercial and the initial edy555 hardware also raises the question whether the DAC to frequency control of the vctcxo is used by the edy555 firmware for small

I built my own VNA similar to the NanoVNA, and I can tell you of my experiences of measuring small and large impedances with it. I built my VNA because it is unclear what license the NanoVNA hardware

Kurt, You are right. I rechecked my random lab F-F and get more like 0.03dB reflection loss at 900MHz. (Operator malfunction.) --John Gord

I see information from other posts that there is a quality issue with the female adapter. Take a close look at the adapter and see if there are any obvious defects. Alan

Hi Dick. The readout fluctuates around 10 dB. That is a significant movement. I would make sure the cables are making a snug connection to the female adapter. Perhaps the cable on channel 1, CH1 is

Thanks, yes I was looking at the original schematic on GitHub by edy555 as I was not aware of the differences. I hope the V2 will have it back, or be layed out in such a way we can solder one. With

[email protected]> wrote: I didn’t take too much notice of the reflection figure you gave - just your quafigures you gave initially, kurt was more observant. A return loss of 0.3 dB at 900 MHz

Yes, I didn’t actually look ar John’s figures - just accepted his comment they were okay. A Rosenberger female female was used as S21 thru during my test but the Dave. Dr. David Kirkby, Kirkby

[email protected]> wrote: There is obviously quite a bit of variation among them. You and Rune find them okay, I find it poor and Kurt even worse. I expect George Orwell would have said, all

Hi Kurt Exactly, the supplied open is pretty poor and has high loss. See attached Yours looks worse than mine, and I thought mine was bad enough! That is why I have not yet published my

Hello Rune, From https://github.com/ttrftech/NanoVNA/releases ChibiOS/RT Shell ch> version 0.2.3 ch> info Kernel: 4.0.0 Compiler: GCC 8.2.1 20181213 (release) [gcc-8-branch revision 267074]

Hi John The one 0.3dB is not much less the what David and I measure so the one from your lab is not optimal. A Rosenberger female female was used as S21 thru during my test but the open was from my HP

Hi David Exactly, the supplied open is pretty poor and has high loss. See attached measurement with the NanoVNA aand NanoVNA saver calibrated with my HP85033C . That is why I have not yet published my

I see on the schematic that the vctcxo has its frequency driven by the DAC output, is this used as a way to have finer frequency steps ?

Dave, I have two of the longer SMA F-F adapters, from two similar NanaVNA kits. I checked them on my 8753D. Both look reasonable to the 6GHz limit of my 8753D. Each shows a 900MHz through loss of