Evan,
Looking at the Antuino schematic, it has an AD8307 at the output of the 25mhz filter
to tell the processor the magnitude of the received signal.
Nothing to tell the processor anything about phase.
So it's an SNA (Scaler Network Analyzer), not a VNA (Vector Network Analyzer)
You might think it needs both phase and magnitude to determine the SWR of an antenna.
But no, it uses a bridge circuit, and senses the difference between what the antenna does
to the signal and what a 50 ohm resistor does to the signal.? It assumes a 50 ohm environment.??
From post? ?
/g/BITX20/message/63034? I suppose R21,R29,R16, and an antenna on P3 would form a balanced
? bridge when the antenna is 50 ohms, CLK1 is driving the antenna and the top of the bridge.
? The ADE-1 RF port sees any imbalance across the bridge.
? CLK2 into the LO port is 25mhz above (or below) CLK1.
The cheapest VNA that I am aware of is the Vector Impedance Analyzer kit that Kees sells,
toward the bottom of this webpage:? ???
Some other VNA's mentioned here:??
/g/BITX20/message/56219But I haven't looked over what's available out there for several years.
Jerry, KE7ER
On Wed, Aug 14, 2019 at 01:14 PM, Evan Hand wrote:
I have ordered my Antunio, and am waiting for delivery, anxious to try it out .? The above comment from Don raises one question for me:? Is it a VNA or SNA.? As I understand the difference is that the VNA measures the phase angle as well as the magnitude of the impedance, an SNA just measures the magnitude of the impedance.? in reading the description on the HF Signals Web Page it states SNA capabilities.
As far as output, you can get a Smith Chart from a VNA, not from an SNA.
So the question is if the hardware would support a VNA application, and and if so does the software provided have both the real and imaginary values of the impedance?
