New answers tagged uhf
0
S11 is one of the S-parameters. It uses 1 port on the VNA to look into something and look at the reflection coming back to determine reflection coefficient / VSWR. If the device was calibrated properly then it can also tell you the complex impedance of what it is "seeing". To calibrate you have to use open, short, and load (99% this is 50 ohm), but ...
1
Some (in fact quite a few) mobile antennas are effectively an "end-fed" design rather than a "ground-plane" design. One way to identify them is that they will generally have a noticeable transformer coil at the bottom (usually enclosed) to transform the impedance. If an antenna's description includes the words "ground-independent&...
0
Ideally you would want four or more radials for each band extending out horizontally. Any antenna intended to be mounted on an HT has performance that is greatly compromised in favor of convenience. It's hard to say what method would work best to improve such an antenna. My advice would be to experiment. Your idea sounds like a reasonable thing to try; ...
4
Welcome to HamSE, Gary, and thanks for an interesting question.
We should be grateful to Russel Renaud, VA3RR, for posting his NEC2 simulation model of the DB2 antenna. Importing the model to the 4NEC2 simulator, we find that the antenna pattern is primarily horizontally polarized:
Assuming the antenna is "in the clear" - that is, no other ...
Top 50 recent answers are included
