DG7YBN / 144 MHz - 70cm / YBN 3+7 SAT
  Last Update Apr. 25th, 2019




.......




Performance Data and Geometry
Building Details
Pattern and VSWR


YBN 3+7 SAT  Compact Yagi for Satellite Operation, handheld or on small tripod



A compact Yagi for 145 MHz & 435 MHz satellite operation, to be used handheld or mounted on a small tripod. Design date of issue: 2019.02.09

  ... this little SAT handheld 70 cm moon bouncing with just 10 w out, see here


YBN3 + 7 SAT by M0ABA

Thomas uses 7 mm grommets in 8 mm holes for 6.35 mm or 5/8 inch elements.



70 cm and 2 m 3D patterns

 




Performance Data

Specs: with 1/4 inch = 6.35 mm elements @ 144.1 MHz

Gain vs. isotr. Rad.   7.1 dBi
Gain vs. Dipole        5.0 dBD
-3 dB E-plane         68.4 deg.
-3 dB H-plane        122.4 deg.
F/B                  -19.3 dB
F/R                   -8.4 dB
Impedance               50 ohms
VSWR Band Width       < 1:1.2 for 144.5 - 146 MHz
Mechan. Length         910 mm
Electr. Length        0.44 λ at 145.8 MHz


Specs: with 1/4 inch = 6.35 mm elements @ 435 MHz

Gain vs. isotr. Rad.  12.2 dBi
Gain vs. Dipole       10.1 dBD
-3 dB E-plane         43.8 deg.
-3 dB H-plane         51.4 deg.
F/B                  -26.5 dB
F/R                  -20.1 dB
Impedance               50 ohms
VSWR Band Width       < 1:1.2 for 430 - 440 MHz
Mechan. Length         900 mm
Electr. Length        1.31 λ at 435 MHz


How many SAT operators have been looking up this design since February 2019?

Flag Counter




Geometry

Table 1: 2 m section, 6.35 mm elements through a 5/8 inch boom,
formast mount with 280 mm offset on rear boom end:




"Ready to saw and drill" data for mounting elements through boom with BC according SM5BSZ's BC.exe:

This table is only valid for:
Boom shape: square
Boom dim: 5/8 x 5/8 inch
Wall thickn.: 1/6 inch = 1.6 mm
Holes in boom: 8.0 mm
Offset rear: 280 mm
Offset front: 30 mm
 


Note: This does include an SBC of 0 mm








Table 2: 70 cm section, 6.35 mm elements through a 5/8 inch boom,
formast mount with 280 mm offset on rear boom end:




"Ready to saw and drill" data for mounting elements through boom with BC according SM5BSZ's BC.exe:

This table is only valid for:
Boom shape: square
Boom dim: 5/8 x 5/8 inch
Wall thickn.: 1/6 inch = 1.6 mm
Holes in boom: 8.0 mm
Offset rear: 280 mm
Offset front: 30 mm
 


Note: This does include an SBC of 1.74 mm plus a correction for the insulators (v-factor!) of 0.7 mm = 2.44 mm






Sketch of Bent Dipole for 70 cm











Building Details

YBN 3+7 SAT - Detail: M0ABA constructed 2m dipole bracket

  

Return Loss 70 cm: -44 dB at 435.5 MHz

VSWR 70 cm: 1.003 at 435.5 MHz



Images on courtesy of M0ABA, tnx Thomas!
Link to MX0CNS facebook for more photos and reports








Pattern and VSWR Plots

Current distribution Elevation and Azimuth plot at 145.8 MHz

 


VSWR plots - simulated 2 m


Return Loss plot - simulated 2 m





Elevation and Azimuth plot at 435.0 MHz

 


VSWR plots - simulated 70 cm


Return Loss plot - simulated 2 m











Moon Bouncing

Though 432.1 MHz is a little off band for the SAT 435.5 MHz Yagi it shows its wideband nature
in an easy EME QSO ... on 2019-05-11 M0ABA / MX0CNS made a 70 cm EME contact with DL7APV, first using 60 w out,
later reducing output to 10 w.

10 w QSO screenshots: MX0CNS was B-26 dB at DL7APV

Take a look at the bright traces DL7APV's signal draws into the Spectran screen on this 7 el. Yagi:









73, Hartmut, DG7YBN



Flag Counter