Do SWR meters make you stupid

Eric Nichols, KL7AJ, published a manifesto entitled “SWR Meters Make You Stupid” announced on eHam in March 2010. Eric is clearly a disciple of Walt Maxwell (W2DU SK), his first announcement states By popular demand, my complete treatise on transmission lines. Approved by Walt Maxwell, W2DU as if Walt’s blessing was an imprimatur from the ham radio church.

I wrote to Eric at that time informing him of several technical errors in his article, and was ignored. He writes in a style intended to appeal to the modern dumbed down ham, a lot of gab with a smattering of numbers to pretend that it has some mathematical basis, integrity even… but the emphasis seems to be on the gab rather than its technical accuracy, light entertainment rather than technically sound. It is always a challenge to educate people without telling them things that are not true.

In February 2014 he relaunched the article on QRZ, and a quick review shows it continues to have the same errors.

Notable errors include:

  • His example of a lossless system comprising tx+ATU+450Ωline+50Ωload explains that when the ATU is adjusted for VSWR(50)=1 and tx output is 100W, that on the 450Ω transmission line VSWR=9 and reflected power is 60W whereas a directional wattmeter should indicate Pf=278W, Pr=178 giving net power to the load of 100W.
  • His discussion of measuring transmission line imbalance discusses some options and vaguely dismisses them as not really scientifically rigorous, but he doesn’t actually give an effective solution which might suggest current balance (or common mode current) is not an important issue.
  • His example of a 1s burst of RF energy sent into a transmission line of 60s propagation delay to a light bulb load, and After TWO minutes, we’ll see the light bulb turn on, for exactly one second is a mix of theoretical and impractical as for the reasons he gives, the light bulb is most unlikely to terminate the transmission line in its characteristic impedance and there is no assurance that there might not be multiple reflections (the source is not described, unless you swallow Walt’s line that transmitters are automagically matched to their transmission line).

No, SWR meters won’t make you stupid, but reading Eric Nichols might!