Yes, with a grounded, shunt fed tower, keep the gamma match in the circuit and sweep. You will still see an R dip from the parasitic element. In fact, the tuning method I describe is well suited to a shunt fed driver. When one (or both) of the parasitics are tuned close to the operating frequency, the driver will need to be re-tuned by adjusting the gamma cap.
When measuring the R value with the analyzer on the tower you MUST LOWER the R scale (vertical axis) as low as it will go on the analyzer. If you have the scale set for logarithmic or most default linear scales you will never see the dip. It is subtle. If you add a parasitic wire element to a shunt fed tower, and it has a good ground radial system, you will see a resistance dip. Steve WZ. From Babcocks iPhone > On Jul 20, 2026, at 8:32 PM, Michael Tope <[email protected]> wrote: > > Hi Steve, > > I watched the video and at the 13:50 mark it says to "sweep just the raw > driven element without any hairpin, LC networks, ununs, stubs, or anything > used to match the coax, just connect the analyzer to the bare element". That > makes total sense for series-fed driven element. However, for a shunt-fed > driven element what is the procedure? Do you first adjust the shunt-feed for > a low VSWR at the design frequency with the all the parasitic elements open > at the base and then subsequently follow the procedure that you describe in > the video? Does the procedure still work if the series gamma capacitor in the > shunt-feed is present? > > 73, Mike W4EF.................... > >> On 7/20/2026 5:06 PM, VE6WZ Steve via Topband wrote: >> Hi Mike, >> >> The K3LR type array is just a vertical 3 el parasitic array. Driver, >> reflector and director. The driven element can be a shunt fed grounded >> tower. It just provides the drive to the two parasitics. Think of a shunt >> fed tower driver like a gamma matched (shunt fed) driver in a typical >> horizontal Yagi. Same thing. >> >> I made a video that explains a method for turning a parasitic array, both a >> 2 element or a three element. I talk about how mutual coupling gives us the >> info we need to adjust the parasitics for max gain or F/B. Even using a >> shunt fed tower: >> https://youtu.be/J8S3iZ9-848 >> >> Steve VE6WZ >> >> From Babcocks iPhone >> >>>> On Jul 20, 2026, at 5:09 PM, Michael Tope <[email protected]> wrote: >>> >>> Thanks, Mirko. I found this video briefly describing Steve's 160 Tx Array >>> with the shunt-fed driven element as it existed before the lift-cable on >>> the crank-up tower broke: >>> >>> https://www.youtube.com/watch?v=VXDTEj0xDJU >>> >>> I don't know if Steve just cranked down the tower when adjusting the >>> resonant frequency of the parasitic elements, or whether he left the >>> tower-up and detuned it somehow. He doesn't really get into that in the >>> video. >>> >>> There is a google drive link below the YouTube video to a paper describing >>> the the array, but the link doesn't seem to work. >>> >>> 73, Mike W4EF.................... >>> >>> >>>> On 7/20/2026 6:47 AM, S57AD via Topband wrote: >>>> Mike, if I recall correctly, VE6WZ uses 160m parasitic array with shunt >>>> feed >>>> tower. >>>> >>>> 73 Mirko, S57AD >>>> >>>> V V pon., 20. jul. 2026 ob 14:04 je oseba Michael Tope <[email protected]> >>>> napisala: >>>> >>>>> Tim, >>>>> >>>>> I am curious, is there any reason why the center tower in that array of >>>>> yours could not be shunt-fed? I suppose that might require de-tuning the >>>>> tower in order to adjust the parasitic elements, whereas with a base >>>>> insulated tower you could just open-circuit the driven elements. >>>>> >>>>> Do you know of anyone who has made this sort of array work with a >>>>> shunt-fed tower as the primary support? >>>>> >>>>> 73, Mike W4EF............ >>>>> >>>>> On 7/19/2026 11:22 PM, Tim Duffy wrote: >>>>>> Speaking of base fed insulated towers on 160... that happen to be 90 >>>>> degrees >>>>>> high (about 120 feet) - by design... I have had this for over 30 years - >>>>> it >>>>> >>> _________________ >>> Searchable Archives: http://www.contesting.com/_topband - Topband Reflector >> _________________ >> Searchable Archives: http://www.contesting.com/_topband - Topband Reflector > > > _________________ > Searchable Archives: http://www.contesting.com/_topband - Topband Reflector _________________ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
