DG7YBN / 144 MHz / YBN 2-8mz
  Last Update Nov. 14th, 2020


.......




Performance Data and Geometry
Pattern and VSWR
Download as File
Stacking
4 x vertical Phased Contest Stack


YBN 2-8mz  28 / 25 Ω Yagi with straight Driven Element



Another variation of the well tested 5-8 series. Focussing on relatively good F/B with gain here is one more specimen. However for this 28 respectively 25 ohms versions many similarities except the origin come to an end. While the 18 ohm version offers a little bit higher gain and bandwidth the 25 ohms version enables us to phase 2 or 4 Yagis more easily with stubs of common 50 ohms coax cable.
These stubs must be odd multiples of 1/4 wl (mind the exact velocity factor at 144 MHz!) like 3/4, 5/4, 7/4 wl ... . For a vertical stack of two of these YBN 2-8mz 25 ohms a length of 7/4 wl per Yagi enables connecting the two at the half way point. As an example uisng Ultraflex 7 with a v-factorof 0.83 this equals 3016 mm including rf connectors.
Design date of issue: 2020.11.16



YBN 2-8mz 3D pattern plot at 144,1 MHz




Performance Data

Specs: with 8 mm elements @ 144.1 MHz 

Gain vs. isotr. Rad.  13.1 dBi
Gain vs. Dipole       11.0 dBD
-3 dB E-plane         41.4 deg.
-3 dB H-plane         47.2 deg.
F/B                  -28.5 dB
F/R                  -22.2 dB
Impedance             28 / 25 ohms
VSWR Band Width       1.39:1 *
Mechan. Length        3485 mm plus 2 x 40 mm offset
Electr. Length        1.68 λ

Stacking Dist. h-pol. (144.1 MHz)
top-to-bottom         2.60 m or 8.5 ft
side-by-side          2.94 m or 9.7 ft

*) as in VE7BQH G/T table = at 145.00 MHz


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Geometry


This Yagi with 8 mm elements on a 20 x 20 mm boom with standard insulators

Ele. 8.0 mm
DE 10 mm
Boom 20 x 20 mm 		 



"Ready to saw and drill" data for mounting elements on boom with BC according DG7YBN for standard insulators
as sold by WiMo, Tino's Funkshop, HF-Kits NL, 7arrays:



25 ohms version


The Drivers diameter is 10 mm for all examples.
The EZNEC model is done with Auto-Segmentation at 380 MHz







Pattern and VSWR Plots

Elevation and Azimuth plot at 144.1 MHz

 


Return Loss and SWR plots - simulated


Elevation plot at 144.1 MHz - 25 ohms version


more or less identical .....







Downloads

None so far.








Stacking 


Stacking Dist.    DL6WU Formula (144.1 MHz)
E-plane               2.943 m
H-plane               2.598 m

Plot and data of 2 vertically stacked YBN YBN 2-8mz using DL6WU stacking distances

Antenna View & Elevation Pattern


Plot and data of 3 vertically stacked YBN YBN 2-8mz using DL6WU stacking distances

Antenna View & Elevation Pattern


Same with lowest Yagi at 4 m agl, perfect groungd assumed


Plot and data of 3 vertically STAGGER stacked YBN 2-8mz using DL6WU stacking distances, 504mm shift

Lowest Yagi 4.0 m agl, highest Yagi 9.2 m agl.


Plot and data of 4 vertically stacked YBN YBN 2-8mz using DL6WU stacking distances

Antenna View & Elevation Pattern


4 x vert. stack with lowest Yagi 4.0 m abover 'Perfect Ground'
F/B approx. -34 dB





Plot and data of 4 vertically STAGGER stacked YBN YBN 2-8mz using DL6WU stacking distances, 504mm shift

Lowest Yagi 4.0 m agl, highest Yagi 11.1 m agl.
19.1 dBi or > 16.9 dBd at close to 42 deg. HPBW in Azimuth with > -35 dB of F/B.



Elevation Pattern

4 x vert. stagger phased stack with lowest Yagi 4.0 m abover 'Perfect Ground'
F/B better -45 dB



Plot and data of classical H-shape bay of YBN 2-8mz using DL6WU stacking distances

Antenna View & Elevation Pattern

  










73, Hartmut, DG7YBN



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