On 7/30/20 7:54 AM, KENT BRITAIN wrote:
I fully understand the layout of the Nano's.I currently own 5 commercial Network analyzers andmy vintage 141T does have a tracking filter when usedas a Scalar Analyzer.
My point is that when you connect one to a BIG outside antenna,
AM Stations, FM Stations, TV Stations, etc can all easily introduceenough RF Voltage to drive it non-linear.
I see the same issue with SDR users.?? They think they can eliminatesignal overload by just telling their laptop to ignore that frequency.
No, when the first simiconductor device goes non-linear, your screwed!
So, if you own a 40 GHz HP VNA, why are you messing with a Nano?They are cute and much easier to carry!?? In fact, I own 3.?? Kent
I'm not sure that you'd actually see enough power from BC transmitters to saturate the front end - I guess it depends on where you are relative to the transmitter.
The MFJ259 are notorious for problems, but that's because they have no selectivity, and the diodes are sensitive to being burned out.
The NanoVNA has a fair amount of attenuation between the two inputs and the mixers. I think you'd need to see over 0dBm at the input before it's a problem.
I don't know that I'd try to measure the Z of an antenna at Field Day with multiple transmitters going, for instance.
I'd be interested to see some actual measured data.
Yes, the SDR folks do get hosed by this occasionally, as do people using lab spectrum analyzers and take out all the attenuation to see that weak signal.
