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Is the 4 trace a firmware thing, or hardware thing
Frank

On 7/20/2019 1:49 PM, Mike Brown wrote:

Hi Alan

You've obviously got a good one there. I have been finding odd calibration
issues and finally worked out it mine is happier up to 450 MHz and not
going too low either, although the issue may be the span rather than the
frequencies. I currently have it set to 1.5 to 450 MHz and am seeing
repeatable results.

I was able to quickly compare mine with a MiniVNA Pro (which works up to
200 MHz) earlier - another budget VNA that costs GBP 380. I wasn't able to
capture screen shots but on the couple of things we tried the results
looked fairly close.

I've attached a photo showing what mine thinks of a dual band handheld
antenna, which looks plausible.

73

Mike


On Sat, 20 Jul 2019, 16:28 alan victor, <avictor73@...> wrote:

Hi Mike,

Here is a 3 pole helical filter centered at 465 MHz. The filter is "C"
coupled so the skirt on the high side rolls more gentle than low side. The
insertion loss and return loss as well center freq are pretty spot on with
expected. The DR on the second pix shows we can see down at least 65 dB and
if I set the reference point to the screen top, perhaps 70 dB. Next, I'll
try the big box. I expect very similar results although if I were to read
the R+jX values at each and every frequency point there will be delta
values. Alan