How to use a simple SWR meter and what it means to your VHF
How do you know that you have a better signal when you tune your
antenna for lowest SWR?
An SWR meter is good for telling you when your transmitter is seeing a
flat 50 ohm load. It is useful as a tuning device. Not much more.
Solid state finals don't like complex impedance's. It causes them to
draw excessive currents. High SWR goes along with reflected complex
impedance's. Also the output circuit is usually fixed at 50 ohms. If
you don't match that you will not get maximum power transfer from the
transmitter.
Your solid state transmitter usually has a power reduction circuit
that reduces power out when it sees a high SWR. So having the proper
match at the transmitter will ensure full power out.
On tube transmitters you will usually not find any high SWR protection
circuits. Tubes are very tolerant on complex impedance loads.
As explained in the ARRL HANDBOOK, reflected power does not reach the
finals in your transmitter. See below again.
Regards
Gary
On Mon, 24 Nov 2003 18:23:34 -0500, "Doug Dotson"
wrote:
So what is the use of an SWR meter if SWR has no affect on
radiated power or stress on the finals? I know for a fact that if
I tune my antenna for lowest SWR, I have a better signal.