[CQ-Contest] TH7 Replacement

[Chris Pedder]

The 4L 20M on a 53' boom appears on p 8-18 of Lawson's book. There is 
another, perhaps less well known, of his designs referred to as a 
PV-4 described by Carl Hueter, KM1H and by Bill Meyers, K1GQ in the 
May 1986 edition of Radiosporting. (Bill Meyer's article originally 
appeared in Scuttlebutt in May 1982.)

On a 0.57 wavelengths boom, this equates to 4L on a 40 foot boom on 
20m. Having built one of these antennas I can say that it looks very 
strange from some angles due to the spacing of elements on the boom. 
Not having a PC at that time, I had to recalculate the element 
lengths, with my taper schedule, by hand. While I balanced it for 
weight, I failed to balance it 'dynamically' and the widely varying 
element spacing played heck with rotators. Young(er) and stupid perhaps.....

Chris G3VBL

At 03:10 09/08/2017, you wrote:
>Check out the W2PV yagi book or the W2PV Yagi design series in the 
>old Ham Radio magazine.  Both of which documented a 4L 20M yagi on a 
>51' boom with big gain and good pattern.  It WAS somewhat narrow 
>banded but one or two extra elements can be added for more bandwidth 
>if desired.
>
>My buddy W5XZ had a pair of these 4Ls stacked which worked very well 
>at his former QTH in LA.
>
>Dave, K8CC
>
>Sent from my iPhone
>
> > On Aug 8, 2017, at 8:10 AM, "john at kk9a.com" <john at kk9a.com> wrote:
> >
> > Gain is a function of boom length however you need enough parasitic
> > elements for the Yagi to work.  The MonstIR DB42 has a boom length of 42.5
> > feet with four loop elements and two straight elements. This is the only
> > MonstIR that I see on the SteppIR site so I am guessing that this is the
> > antenna you are referring to.  Are only the loop elements motorized? 4
> > elements on a 42.5 foot boom seem to be pretty big spacing for 20m and
> > higher.  For example my homebrew 4el 20m OWA beam is pretty wide spaced
> > and it only has a 32 foot boom.
> >
> > John KK9A