[amsat-bb] dual band vhf/uhf antenna

[Hasan al-Basri]

If the design is good in the first place (interlaced yagis),there should be
no problem.

I am using an interlaced yagi , 2m and 70cm and a *common feedpoint, *that
is, no duplexer at the feedpoint a single/common element feed. All elements
for both bands are in the same plane.

It was designed to be used that way. It is an EAntenna, 5 EL on 2m, 8 EL on
70cm and it works beautifully on the LEO birds. I run strictly mode B and
have the antenna mounted atop a 48' tower and 15' of mast. It is vertically
polarized with a fixed 15 deg upltilt (elevation), eliminating the need for
an elevation rotor, as the gain at the horizon is only down 1 dB.

Judicious use of Comet duplexers or triplexers as filters works out very
well.
I can hear myself at an elevation of -0.5 deg easily on nearly all the
LEOs. No intermod , no desense because duplexers make such good filters for
satellites.

You can see my QRZ page for pictures of the antenna in place at 65' (fed
with 1/2" hardline)

73, N0AN
*Hasan*


On Sun, Feb 16, 2020 at 6:09 AM Jackie Dander via AMSAT-BB <
amsat-bb at amsat.org> wrote:

> I built the combination dual band 2meter/70cm antenna found at WA5VJB's
> webpages. I chose the 5 elements on UHF forward and 2 elements on VHF rear.
> All elements are in the same plane.
> I now read elsewhere that in-same-plane uhf/vhf elements can interfere with
> each other. I visited the Arrow website and see their LEO antennas are
> opposing for uhf/vhf.
> My question is if i made a mistake building the uni-plane version? Why did
> WA5VJB has such success?
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