The proposed antenna is useful for transportation in the trunk of a car in a collected form - dimensions: 1000 x 980 mm.

The short UDA-YAGI Antennas are mainly used for communication through repiteters and for local QSO at 145.500 MHz and for receiving the International Space Station (ISS) for 145800-145.825. However, with good passage from a high height, connections in SSB and FM are possible at a distance of 150-200 km.

The advantage of Uda-Yaga over the pin antennas of the Ground Plane type is a higher reinforcement of the directed antenna 8-9 dbi, against 2 DBI at the pin, and spatial selectivity (receiving signals only from the desired direction), direct power with a cable 50 Ohms (good coordination thanks to computer design-there is no need for 1/4-wave transformers).

Material for manufacture - aluminum tubes with a diploma of 8 mm. They can be bought in construction hypermarkets "Максидом","OBI" or "Custorama", order in the online store "Все инструменты" and others.

Option 1. Compromise between increased G and f/b suppression with minimal dimensions

• Strengthening g = 8.8 dbi.
• Suppression of the reception on the side and behind f/b = 16 DB.
• A wide strip, good approval of the antenna with a cable at the KSV <1.1: on the site 143-147 MHz.
• The width of the main petal of the focus diagram with vertical polarization is 90 degrees
• The width of the main petal - // - with horizontal polarization - 60 degrees.
• The optimal distance in vertical stack and vertical polarization is 1.77 meters (upper antenna on h = 4 meters, stack down)

• The optimal distance in vertical stack and horizontal polarization is 1.38 meters (upper antenna on h = 4 meters, stack down)

  Antenna sizes:
  Material - aluminum tubes with a diameter of 8mm.

Download model mmana 4 elements for the range 144 MHz:
4E-145_8mm.ma.zip

KSV at an altitude of 4 meters:

Relationship F/B and strengthening for horizontal polarization (installation height above the ground - 4 meters).

Option 2. High relation F/B, the number of elements is 4

The dimensions of the reflector are enlarged, so the dimensions of the antennas slightly go beyond 100 x 100mm.

• Strengthening g = 8.0 dbi.
• Suppression of the reception on the side and behind f/b = 21 db.
• A wide strip, good approval of the antenna with a cable at the KSV <1.1 on the site 143-147 MHz.
• Width of the main petal of the orientation diagram with vertical polarization - 104 degrees
• The width of the main petal - // - with horizontal polarization - 64 degrees.
• The optimal distance in vertical stack and vertical polarization is 1.6 meters (upper antenna on h = 4 meters, stack down)

• The optimal distance in vertical stack and horizontal polarization is 1.0 meters (upper antenna on h = 4 meters, stack down)

  Antenna sizes:
  Material - aluminum tubes with a diameter of 8mm.

Download model mmana Antennas 4 elements for the range 144 MHz:
144_4e_FB.MAA.ZIP

The vibrator is split. Symmettration with a shut -off throttle. Correction when attaching to a metal boom through a spacer (plumbing clip for fastening polyethylene pipes) is not required.

Option 3 for comparison: Uda Yagi 3 elements

• Strengthening g = 7.4 dbi.
• Suppression of the reception on the side and behind f/b = 17.5 db.
• A wide strip, good approval of the antenna with a cable at the KSV <1.1 on the site 144-146 MHz.
• The width of the main petal of the orientation diagram with vertical polarization is 114 degrees
• The width of the main petal - // - with horizontal polarization - 67 degrees.

You can get a rated F/B to 20 dB, but at the same time the input resistance falls up to 43 Ohms.
Therefore, with R = 50 Ohm parameter f/b = 17.5 dB.
.
Antenna sizes:
Material - aluminum tubes with a diameter of 8mm.

Download the MMANA model of 3-elements for the range 144 MHz:
3l.Maa.zip

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