Ken, you are about to start off on a grand journey.
There is much rubbish physics bandied about regarding antennas. To
get a feel for what's going on permit me to suggest the A.R.R.L.
"Antenna Book", 15th Edition, 1988. The foreword is by John Kraus, W8JK;
if Kraus thinks it's alright...then it's alright. Don't settle for the
later editions, look around for that one. It has been valued for decades
so there will be plenty of them around at ham flea markets and out on
the web. I have even seen that book cited in learned discourse.
So far as an "A" to "B" comparison goes, just take screen grabs of
Rune's display. "Screenshot" is in use here on a Linux system and then
use G.I.M.P. or similar to overlay one graph upon another.
John
at radio station VE7AOV
+++++
On 2019-09-20 10:33 a.m., Ken Buscho wrote:
Hi, Folks,
My whole NanoVNA process started because I went out on eBay looking for an antenna analyzer for ham VHF/UHF use and got my white model because it intrigued me at what was being done at that price point. No prior personal experience with VNAs, although I've been aware of them for years. Big learning curve to get started, but it did almost everything I was looking for once I could see SWR and a Smith Chart. It's been well worth the $60, and I'm getting a VNA education to boot reading here.
I say almost because I would like to be able to get some values to at least compare HT Antenna A to HT Antenna B for gain. To get started, I put a test antenna on CH0 and a reference antenna on CH1. I can tell the CH1 antenna is "seeing" the CH0 antenna because logmag dB values change with/without something on CH0, and I can also see that dB values go up/down as antenna distances change.
What I'm looking for is suggestions on how to do this the right way, or at least a better way. Now I'm using a scanner-type antenna for reference, it's about 30cm/12" away from the test antenna. I'm looking for suggestions on ref antenna type/spacing, and also a calibration protocol to make this choice useful. Nothing really fancy, I just want to get some data so when someone shows up with what they think is an antenna that's cooler that what they (or someone else) already has, I want to have some numbers to avoid a food fight and/or be able to objectively evaluat/comapre the two. Suggestions? Issues?
Appreciate the input...
Ken Buscho
KB6KOB
--
