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Title: Mini / Micro VNA & Filter Post by: NC2W on February 25, 2021, 10:43:36 PM Again, this topic starts with the following disclaimer: "I am not a RF Design Engineer" (with that out of the way), here's my question:
Are the cheap VNA's (such as the SAA2N) accurate/reliable/effective for use, to measure the frequency response of a properly terminated multi-pole filter? If I confirm that a seven pole Low Pass Filter has the right frequency response, can I consider the results as accurate? Can I translate these results (assuming no loose joints, adequately rated components) into a basic assurance the filter will perform? I wanted to sweep two filters I've found laying around, and put them in something, if they appear OK. Title: Re: Mini / Micro VNA & Filter Post by: M0VRF on February 26, 2021, 02:33:59 AM Yes, I purchased a nanoVNA over a year ago and tested it against my trusty HP8712. Results of the measurements were within +/- 0.2dB. I wouldn't hesitate in recommending how useful they are.
Try and find one in a decent case. JB. Title: Re: Mini / Micro VNA & Filter Post by: W1ITT on February 26, 2021, 11:57:26 AM I will second the previous recommendation from M0VRF. I have a 8714C HP network analyzer and also did some quick checks of the NanoVNA and found it very close, and plenty close enough to do some real work. I have an extra one in my kit to give out to customers if there needs to be some palm grease applied. AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands
Mine are the $50 dollar ones, but the latest iterations have a metal case and two Type N connectors facing the user, which I would find more convenient. I've seen that one on FleaBay for about $115. If I didn't already have four other network analyzers (as well as a good old GR916 impedance bridge), I'd buy one. But for the time being, I'm exercising restraint. But, the short answer is... Get One ! 73 de Norm W1ITT |