Author Topic: Minivna Tiny Reflection Measurement Issue  (Read 608 times)

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Offline vaughn22

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  • Posts: 4
  • Country: us
Minivna Tiny Reflection Measurement Issue
« on: November 26, 2017, 12:26:18 am »
I was wondering if someone could help me with this. I recently purchased an MRS Minivna Tiny and I'm observing something weird. The port terminations are supposed to be 50 Ohm, but when in reflection mode, I sometimes get different results depending on whether the 2-port device I'm measuring is terminated with a standalone 50 Ohm load and when it's terminated on the DET port. Obviously, neither termination is EXACTLY 50 Ohm, but the difference is too substantial for it to be normal variation. I observed this around 140 MHz by the way.

Is the DET not really 50 Ohm? Is there uncalibrated crosstalk between the DET and DUT ports when in reflection mode if both are connected? what's going on???
 

Offline jjvicente

  • Newbie
  • Posts: 1
  • Country: es
Re: Minivna Tiny Reflection Measurement Issue
« Reply #1 on: January 17, 2018, 08:00:36 pm »
Hi,

I am deciding whether to buy one MiniVNA tiny and I´ve done some of researching about it.

It seems that measurements are not consistent until it reaches its working temperature ~50ºC. Maybe this can be the root cause of your issue...
 

Offline hagster

  • Frequent Contributor
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  • Posts: 259
Re: Minivna Tiny Reflection Measurement Issue
« Reply #2 on: January 18, 2018, 05:12:19 am »
I tried one a few years ago and though it was very painful use. Today I had a go with an ELAD SNA. Again I thought that was totally useless too.

The KC901 looks like about the best cheap VNA that I have seen. There is a review on The Signal Path.
 


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