The other day a ham friend suggested using a coil ("hairpin") to match the low impedance of a well-radialed inverted L to 50-ohm coax. This struck me as a potentially-attractive alternative to a ser
The reason to use a series capacitor is to electrically lengthen the antenna wire, driving the high current point up the vertical section, for more efficiency. The capacitor electrically shortened th
Wasnt that called a gamma match in the past? -73- Frank KG9H kg9hfrank@gmail.com _________________ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Simple, resonate the vertical at about 1.9mhz. Then add the inductance across the feed point which may well be in the 2-3 micro Henry region. But use a variable L and slightly alter the L or top load
You mean physically lengthen the wire. Unfortunately, the added horizontal radiation may defeat the intended purpose. Ir pays to model. Wes N7WS On 9/1/2019 12:07 PM, FZ Bruce wrote: The reason to
Pete, broadly in matching theory, a series-capacitor match can often be replaced with a series L and shunt C to ground. Often the topology will be chosen on component value reasonableness and conveni
That's exactly what I do; shorten the radiator to create a capacitive feedpoint Z and shunt that with inductance to make a resonant impedance step-up at the desired frequency. That said, my original
When I did my Inverted L with the elevated radials, I think the impedance was about 38 ohms. I decided to wind a 1.5:1 Unun based on Cecil's book on a K Mix. That brought it nicely in line to about 5
I did and it was easy and worked well. I could not find much info (Internet found one picture and not much in handbooks for a hairpin on 160). I "WAGed" it and took #10 solid wire and wrapped 12 turn
Hi Pete, Here is picture of coil I made to tune Inv. L at 9Y4 with 15-20 Ohm impedance. It was tuned in 2 steps: 1. calculate and wound coil to rise R close to 50 Ohm 2. adjust horizontal wire length
Plastic bottles are the coil form of choice on DXpeditions. Excellent. Mark N5OT Here is picture of coil I made to tune Inv. L at 9Y4 with 15-20 Ohm impedance. It was tuned in 2 steps: 1. calculate
A hairpin works great on non-OWA Yagi's so why not use it on a vertical? I used a THHN primitively made hairpin coil on my P40A 160m vertical and it really made the transmitter happy. You will have t