Re: Does a low SWR mean your antenna is a great performer?


John Haskell <jasm2213@...>
 

What George quoted from ham.stackexchange is correct.

To take it a bit further, SWR can be pretty much ignored.  If your solid state transmitter functions with normal output power versus shutting down, then SWR really does not matter much for most installations.  This is particularly true at HF where cable loss is minimal.  At UHF and with a long transmission line SWR can cause unacceptable losses.  

Here are a couple of examples of SWR versus loss using inexpensive RG-58.

Assume 7MHz and 75 feet of RG-58.  The cable loss is .9dB with a SWR of 1.

But what if the SWR is 2:1?  The extra loss due to this SWR is .2dB, e.g., negligible.


For a mobile set up on 442.1MHz..   Many people go nuts with low loss cables.  Not me. I use RG-58 in the car.  Here is why.  For 442MHz, 10feet of cable, and a 2:1 SWR, the additional loss due to the 2:1 SWR versus a perfect match is .2dB.  I do not believe you will notice that extra loss.


I have been considering putting a transmission line/SWR presentation together for TLARC in hopes of dispelling some of the common myths.  If there is interest let me know.  Maybe that will get me off my butt.

73, K1AT

Join TLARC@groups.io to automatically receive all group messages.