I personally think you have created a lot of problems on all bands with 3 large towers so close together.
70ft between two is acceptable. But having one in the middle can cause a number of problems in my mind... Ray, N6ve On Thu, Sep 27, 2018, 2:23 PM Joe Subich, W4TV <[email protected]> wrote: > On 2018-09-27 5:01 PM, Edward via Topband wrote: > > > > I have three crank-up towers spaced 35' apart. T > > With towers spaced 1/16 wavelength, they will almost certainly > all be coupled to each other. The coupling will be greatest > when they are nearest to resonance. > > Your "tower #3" is probably very close to resonant on 160 meters > depending on the top loading. As a first approximation, take > 1/2 the boom length of the longest boom yagi and add it to the > height of its attachment to the mast. If, for example, you have > a 32' boom 6 meter yagi 15' up the mast -> 106 + 15 + 16 = 137' > > I would strongly consider gamma (or omega) matching the 160' tower > and then using skirts to detune the other two towers. > > > What kind of separation is needed for 2 ele array? > > Typically somewhere between 0.20 and 0.25 wavelength. If they are > phased it is much easier if they are identical (otherwise one needs > unequal currents to account for the differences in height and > impedance). > > 73, > > ... Joe, W4TV > > > On 2018-09-27 5:01 PM, Edward via Topband wrote: > > Jon, > > > > I have three crank-up towers spaced 35' apart. Tower #1 is 89' plus 20' > mast, with some antenna top loading. Tower#2 is 70' crank up with 20' mast > with minimal antenna too loading. Tower #3 is 106' crank with 20' mast plus > top loading. > > > > What kind of separation is needed for 2 ele array? > > > > Thanks, > > Ed NI6S > > > >> On Sep 27, 2018, at 11:00 PM, Jon Zaimes <[email protected]> wrote: > >> > >> Either crank up should work fine with adequate radial field. > >> > >> Inverted L may suffer from interaction with the towers. > >> > >> Depending on tower spacing and orientation, you may be able to feed > both in a 2-element array. > >> > >> 73/Jon AA1K > >> Www.aa1k.us > > > > _________________ > > Topband Reflector Archives - http://www.contesting.com/_topband > > > _________________ > Topband Reflector Archives - http://www.contesting.com/_topband > _________________ Topband Reflector Archives - http://www.contesting.com/_topband
