[Elecraft] Less Than Perfect Antennas [was Flumoxed]

[Bob McGraw K4TAX]

While I agree with Jim's information, I would point out the flat dipole 
will have 3 dB more signal off of its broadside 0/180° as compared to 
that of a inverted V dipole off of its broadside.  At the same time, the 
inverted V dipole will have about 4.5 db more signal off of its ends 
90/270° as compared to that of a flat dipole off of its ends.

It appears what one loses with one antenna is made up with the other 
antenna depending on azimuth and apex angle of the inverted V being 
somewhat greater than 90°.    In fact it appears that the Inverted V has 
almost an omnidirectional pattern at an elevation angle of 25°.  Fig 9.6

If a close match to 50 ohms is required, it is best to adjust the angle 
for lowest SWR while maintaining resonance by adjustment of the length.

Reference:  ARRL Antenna Book, 22nd Edition,  9.1.3 Inverted-V Dipole

73

Bob, K4TAX


On 12/7/2018 6:51 PM, Jim Brown wrote:
> On 12/7/2018 12:55 PM, Dick Dickinson wrote:
>> Why is there so much promotion of dipole antennas over inverted vee 
>> type antennas?
>
> As has been noted, an inverted vee is a compromise dipole -- the sort 
> of thing you can rig with a single support. A flat dipole with its 
> center at the same height as the inv vee will have a dB or two more 
> gain, and the directional pattern will be the classic "figure-eight" 
> pattern with broad peaks broadside to the wire and nulls off the ends. 
> Inverted vees tend to lose the nulls off their ends. All this stuff is 
> in the ARRL Handbook and Antenna Book which every ham should own and 
> study as we have time.
>
> For rigging heights that are possible for most hams, horizontal 
> antennas for 160 or 80, and 40M over flat terrain produce more gain at 
> greater height. It is a fallacy that an antenna must be low to work 
> short distances. Low antennas radiate LESS signal at high angles than 
> high ones. I published a study of this several years ago. It's here. 
> http://k9yc.com/AntennaPlanning.pdf beginning on page 10. Field 
> strength at 70 degrees vertical elevation just starts to fall off as 
> it is raised to 1/3 wavelength. That's 45 ft on 40M, 90 ft on 80M, 180 
> ft on 160M.
>
> 73, Jim K9YC
>
>
>
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