Please reread my msg...my coax is 1m long. It's the PC SW that is not right.
On Wed, 5 Aug 2020 at 9:37 PM, cldp@...<cldp@...> wrote: On Wed, Aug? 5, 2020 at 08:07 PM, Larry Rothman wrote:
I was playing with the TDR on my H along with using your NanoVNA.exe 0.1.67
and they don't match.
The Nano shows the correct length of my coax at just over a meter but your app
shows close to 4X as much.
Is there an issue or did I mis-configure your app?
See the two images.
Thanks,
Larry
Larry, you should set the nanovna software to a way higher frenquency stop, the picture I see display 494m (which is a low frequency stop), if you set the stop frequency at 900MHz, you should have a maximum of around 4m which is a much more realistic measuring range for the coax lenght I see on the other picture...
You should set CH0 trace to LINEAR and clear all other traces, then go to DISPLAY, MORE, TRANSFORM, turn ON LOW PASS IMPULSE and set TRANSFORM ON. Set start frequency at 50kHz and stop frequency at 900MHz, you should get the right lenght on both VNA and software. The lower the stop frequency is, the longer measure you will get. At 900MHz stop, you should see around 4m which fit the lenght of coax you currently have.
