All the Analog Devices isolator chips seem to specify an input to output capacitance in the region of 2pF, which is quite good, and comparable to the Coilcraft broadband RF transformers. Using an isol

Hi Bruce, Agreed, assuming the radio presents a 50 ohm source and the antenna is a 50 ohm load, a 10:1 SWR ratio would equate to approximately 5dB mismatch loss, and 3:1 would be only just over 1dB. H

It depends on where you are located, but there are quite a lot of them covering VHF / UHF http://www.websdr.org/ map view at the bottom of the page Also https://www.receiverbook.de/ Map view https://w

Not entirely true, some are better than others, and others, usually fakes, are terrible. Fortunately, as stated, most handhelds are fairly tolerant of a high SWR, but that's not to say that the antenn

Notes on how to convert BIN to DFU using DFU file manager web link using Google translate https://translate.google.com/translate?depth=1&rurl=translate.google.co.jp&sl=ja&sp=nmt4&tl=en&u=https://cho45

Try looking in the files section https://groups.io/g/nanovna-users/wiki#Sources https://groups.io/g/nanovna-users/files/Dislord%27s%20Nanovna%20-H%20Firmware

If you can afford it then it's worth considering the upgrade, but I was trying to indicate something that could probably be considered to be the next step up from an RTL dongle. Airspy is also worth l

The other problem with using the RTL-SDR.com V3 in direct sampling mode is that reception higher than 14.4MHz is above the sampling rate, so it has limitations and unless a suitable filter is used ahe

That's probably because your antenna is inherently balanced and the feed-line is adequately decoupled by means of a balun or similar. The main problem is with unbalanced antennas, that have a tendency

Remember that anything connected to the antenna system becomes part of it. For example if you disconnect the radio in order to connect the NanoVNA, you change the antenna system. If you change a cable

Great, thanks for that. I'd already looked through the NanoVNA references and performed a Google search but couldn't find it.

Hi Martin, Yes that's the sort of thing, but my understanding is that it is an Android application, but I've not been able to find it. Do you have a link you could share ? Regards, Martin

Hi Arie, Agreed. I think I've missed the window of opportunity to ask for stuff like this, as the firmware and software is now relatively stable and any updates and enhancements tend to be 'few and fa

Hi Alan, Yes that was my requirement. I was working my way though one of Owen Duffy's recent blog posts https://owenduffy.net/blog/?p=19276#more-19276 I agree with his comment that having the Admittan

Do any NanoVNA firmware or software versions support display of the Smith chart Admittance scale ? If not, is anyone prepared to add it ? It's useful to have for antenna matching problems. - Regards,

Exchanging emails with Steve at the time, I'm aware that there was a lot of interchange of information regarding the subject between various key amateurs. This K9YC presentation is probably the most r

Thermographs attached. The first shows a 4:1 Unun wound on a low permeability core the second shows a 4:1 Unun wound on a high permeability core. Taken from this document, which I wrote when I first s

My Antennas also used to sell a high power (5kw 2-30MHz) 1:1 balun using cascaded sections. Probably two stacked mix 61 on the left and two stacked mix 43 or 52 on the right (but that is just a guess)

Hi Dave, Interesting stuff, as always a learning experience and as you say very much a work in progress. Steve, G3TXQ (SK) has some additional charts on his chokes webpage , which are a good starting

Hi Dave, Great stuff, I'm pleased that you have been motivated to make the measurements, and I'm keen to discover the outcome. Ideally you would be able to sum the individual amplitudes and phases of