开云体育

I am using a NanoVNA H4 and NanoVNA-App for SWR display. I connected my end fed half wave antenna to the CNA and compared the two graphical displays. Both the NanoVNA and H4 displays were set for

Based on my limited knowledge I think with regard to L networks there are choices in topology, depending on antenna impedance and desired phase shift in the L network. Also practical concerns such as

B. Whitfield Griffith, Jr., "Radio-Electronic Transmission Fundamentals," McGraw-Hill, 1962 discusses the design of L-networks and provides graphical methods for such designs. ARRL used to sell this

Thank you everyone for responding. Last time I measured an AM broadcast antenna I used a Delta Electronics OIB-3 operating impedance bridge. Using the Delta OIB the measurement would have been

There is an 80dB round-trip loss through that attenuator; the analyzer does not have enough dynamic range to make sensible measurements through such a high loss. Best regards, Don

The other advantage is that some VNA's like the Anritsu Sitemaster and Cellmaster can overcome some interference. My Anritsu can send a coded signal that it can use to ignore the interference. If the

Thank you for all the superb replies. I'm looking for a source that either has the relevant formulas or, where I can figure out the formulas. Ultimately to implement them in some form of auto tuner.

Yes I think that's the problem because I did exactly that with my H4 and got the same result. I flashed it again with the correct variant and it recovered. It's easy to miss the "4" when selecting the

These nanoVNAs have a smaller dynamic range than the (much more expensive) professional VNAs. With a 40 dB attenuator, the signal from the VNA is attenuated by 40 dB on its way from the analyzer to

Thank you David. I made a 40 dB Tee attenuator and did the open-short-load-save calibration at the end of the attenuator not connected to CH0. Maybe I did it incorrectly, because Nano VNA appeared to

Port CH0 ideally presents a 50 ohm resistive impedance to anything connected to it. If an attenuator is needed, it should have a Pi or Tee form, so that a 50 ohm resistive impedance is still presented

Although the ARRL Handbook states, without qualification, that the shunt element always goes on the high-Z side (2021 Handbook, the latest I have), that is strictly true only when the impedances to be

If I may ask a follow up questionsabout Nano VNA-H. 1. Is port CH0 input a 50 ohm resistor load? 2. If #1 is correct, would proper attenuator implementation for the port be a series resistor, to form

The last FW is the 1.2.24 the last DisLord app version is 1.1.215 now. This last FWs for H and for the H4 also included the exe file,

You probably flashed the wrong firmware variant, you used H version instead of H4 version.

A couple of things to consider: - When you say "measure the impedance of the antenna" in this case you are really measuring the impedance at the end of the coax feedline. It will be much different at

Also, know that with L-Networks, the shunt element goes on the high-Z side. Dave - W?LEV -- Dave - W?LEV

Hi Andrew. You can also apply a formula, use a pencil and paper and a calculator and obtain a simple match that will accomplish most Z matches to an antenna. If you have a representative frequency,

SimSmith includes various matching topologies as part of the Smith Chart presentation: http://www.ae6ty.com/ Dave - W?LEV wrote: -- *Dave

Hi Andrew For me, SimSmith/SimNEC is the right software to do those calculations. Very helpfull. 73 - Antonio EA7HJ