Additional loss due to VSWR – a quite flawed concept

The concept of “additional loss due to VSWR” is so engrained in Ham mythology.

Screenshot - 01_06_2014 , 16_30_10

Here it is detailed in the latest version of TLW announced in QST June 2014. On the second last line TLW lists “additional loss due to SWR” as 0.003dB, which seems ok in relative terms as the cable is nominally matched (VSWR=1.03). Continue reading Additional loss due to VSWR – a quite flawed concept

OCF dipoles

Off centre fed (OCF) dipoles are very popular with Hams on HF.

Many claims are made for variations of the theme, but the essential common feature is that the offset feed point provides a feed point impedance that is not too unsuited to 50Ω coaxial feed line at the fundamental resonance of the dipole and half wave harmonics. Continue reading OCF dipoles

TLW v3.24 checkout

I am often asked for recommendations for a replacement for TLLC (Duffy 2001).

The announcement of an update to TLW by ARRL / N6BV in June 2014 QST flagged a possibility.

Screenshot - 13_05_2014 , 15_58_04

Reviewing the available cable types, Belded 8215 (RG-6/U type) was tested for loss with a 75+j0Ω load (approximately a matched load) at 1MHz, and the result of1.147dB does not reconcile with the Belden datasheet showing 1.3124dB, an error of -13%. Continue reading TLW v3.24 checkout