In the light of Small transmitting loop calculators – a comparison a reader asked my thoughts on yet another small transmitting loop calculator, KB0YH’s STLcalc v2.05. There are lots of small loop calculators published, and yes, I have added to the number. Most are some form of elaboration of formulas published by (Hart 1986), and given … Continue reading KB0YH’s STLcalc v2.05
At 4NEC2 plots of STL VSWR and 4NEC2 plots of STL VSWR II I explained a method of working around a limitation of 4NEC2 values for Zo that can be applied using the Settings menu. I can advise that exactly the same change works in 4NEC2 v5.9.3 It appears that 4NEC2 enforces a requirement that … Continue reading 4NEC2 plots of STL VSWR II (v5.9.3)
(Purdum 2020) describes a small transmitting loop (STL) which is a little novel in that it uses an arrangement of four circular conductor loops, two in parallel in series with the other two in parallel. The article goes on to claim some pretty extraordinary efficiency calculated from radiation resistance for a loop structure that is … Continue reading Review of W8TEE, AC8GY STL (Radcom Feb 2020)
Conintuing from 4NEC2 plots of STL VSWR II, this article is a tutorial in using 4NEC2 to determine the Half Power Bandwidth of a simple model of the main loop. The model is drawn from AA5TB’s calculator’s initial values. The model is in NEC-4.2, and is a 20 segment helix in free space, and tuned … Continue reading 4NEC2 plots of STL VSWR III
At 4NEC2 plots of STL VSWR I explained a method of working around a limitation of 4NEC2 values for Zo that can be applied using the Settings menu. I asked the developer to consider a change, but I gathered that he regarded 4NEC2 to be at End Of Life. It appears that 4NEC2 enforces a … Continue reading 4NEC2 plots of STL VSWR II (v5.8.16)
STL propaganda indeed: dipole – STL pattern comparison compared the patterns of a Inverted V dipole and STL, both configurations typical of SOTA deployments. Seeing some pretty wild extrapolations to a vertical quarter wave with elevated radials, again typical of SOTA deployment, this article presents a comparison of all three using NEC-4.2 models. See STL propaganda indeed and STL … Continue reading STL propaganda indeed: QW vertical – dipole – STL model pattern comparison
At STL propaganda indeed a realistic model was developed of the Chameleon P-Loop2 on 20m, similar to that used in the experiment Comparing the performance of an inverted vee dipole with a small transmitting loop on 20m. This article presents NEC-4.2 derived radiation patterns for both the loop and Inverted V Dipole used for the experiment using data … Continue reading STL propaganda indeed: dipole – STL pattern comparison
Recent postings to List your favorite SOTA antenna on QRZ.com referred to an experiment Comparing the performance of an inverted vee dipole with a small transmitting loop on 20m as propaganda. The experiment above states The manufacturer of the loop gives a calculated efficiency of 39.754% at 14174 kHz. This is very similar to that claimed by Chameleon of … Continue reading STL propaganda indeed
A correspondent has been tearing his hair out trying to replicate my VSWR plots of some STL. Above is an example where the Zo has been set to 0.0901847Ω which is the feedpoint impedance of the loop at resonance. Last update: 6th June, 2017, 1:00 PM
NH7RO describes his loop project at Building a 7-foot diameter QRO STL for 40M in my HOA backyard. The loop appears to be made from 7/8″ copper tube, and is 7′ in diameter. He estimates its efficiency to be 66% and initially reports I’ve got it less than 4 feet above ground yet it tunes … Continue reading NH7RO 7-foot diameter QRO STL for 40M