Sizing details for several 2 to 4 element beams from 10m to 70cm
EI7BA Multiband Cubical Quad
It covers six bands 20m to 10m on HF and also 6m. It is a Boomless (spider quad gem quad) design. It uses Glassfibre arms (a must). It uses a single coax line to a homebrew antenna switch. From there a seperate feedline goes to each of the Driven Element feedpoints. There is a homebrew Choke Balun at each feedpoint.
Performance
I have no accurate method to measure forward gain but I reckon it is the text book 6 to 7 db. F/B ratio is consistently 5 to 6 S points on my TS850 S meter on all bands 20 - 10m. I don't know how many dBs per S Point for my TS 850 but it is surely at least 3dB per S Point. So this translates to a minimum of 15 dB and arguably as high as 30dB. As with all 2 element Quads It has a wide beamwidth about 60 degrees.
ADDENDUM.. An extra two bands..!
I have added three elements for 6m and 2 elements for the European 4m (70mHz) band to the existing spider, and on a seperate 6ft boom which is clamped to the spider, I have 5 elements for 2m, and 9 elements for 70cms.. A grand total of 11 bands..
Copper Cactus Dual-Band Super J-Pole Antenna Project
This home made j-pole is easy to build and sturdy. I have had very good results working with copper J-Poles, so I built my refined version of the classic J-Pole. I then added a short insulated section, the extra half wave of vertical length, and the needed half-wave matching stub.
Home Brew dual band mobile antenna
This antenna is just a 1/4 wavelength resonator for both UHF and VHF band. It provides no GAIN as compared to other multi-section design. Yet it has the advantage of better stability against surrounding influence (e.g. different mounting method, unexpected reflection by surrounding objects, difference in stray capacitance between test bench and operating field ). The antenna consists of two sections. The lower section is a conductor cut to resonant on UHF band. The upper section is a coil which serves two purposes. For UHF band, this coil is a RFC (radio frequency choke). It blocks UHF frequency energy to flow through upper section. For VHF band, this coil enhances the inductance provided by lower section. The resultant inductor, together with surrounding stray capacitance will form a VHF resonant circuit and becomes the VHF antenna.
4 6 and 10 element Yagis for 70cm
Yagis for 70cm. Simple straight dipole with bazooka balun. Optimised for forward gain.
10 ele 11.8dB forward gain 22dB front to back ratio.
6 ele 9dB forward gain 13dB front to back ratio.
4 ele 7.6dB forward gain 14dB front to back ratio.
