AOR DIRECT - DA753G

DA753G - compact discone aerial

The DA753G aerial is designed to receive across the frequency range of 75MHz to 3000MHz (3GHz) employing a compact discone configuration. The small size and relatively light weight design is ideal for installation in a confined space such as an apartment.
	Assembly Upon unpacking, take time to locate and familiarise yourself with the parts. 1. Securely attach the support pipe to a suitable mast (not included) using the U-shape bolts. 2. Feed the coax cable (N-type plug end) through the support pipe and connect to the N-type socket of the main aerial loading base. 3. Securely fix both the loading base and the support pipe together using the cross head 'aerial fixing screw' and spring washer. 4. Install all six disc elements (small) and six cone elements to the matching holes as per the diagram. Two of the cone elements have loading coils and are installed facing each other on opposite sides (180 degrees). Use a spring washer on each element, screw the element into the loading base as far as it will go then tighten the locking nut using a spanner. 5. Make sure that each aerial element is correctly installed with nuts and washers in place and re-tighten as required. Tuning Over the 144MHz band, optimum resonance can be obtained by re-calibrating the adjustment rods which are located at the end of the two loading coil elements (there is no adjustment to the top loading coil). Use the allen key to loosen the grub screw and adjust the sliding rod. Repositioning of the rod by 1cm will vary the resonance point by 2MHz (longer is lower frequency). Make sure the grub screw is re-tightened.
Warning Sensible precautions must be taken while assembling & erecting the aerial in order to prevent any accident or damage to personnel or property. It is recommended that the aerial is regularly inspected for loose nuts and bolts. Make sure that the aerial remains stable all the times. Do not use the aerial for non-intended purposes other than receiving radio signals.

Specification

Receive frequency 75MHz - 3000MHz
Impedance 50 OHM
Type of connectors N-type socket protected by support pipe (N-P)
Height 0.87m
Weight 690g (aerial section only)
Resistance to wind speed 40 m/sec
Pole size 20-30mm diameter
Cable 10m RG58A/U (N/BNC plugs)

Note, all measurements and weight are approximate.

Parts supplied - quantity

Main aerial (loading base) - 1
Disk element, 10cm with cap - 6
Cone element, 26cm with cap - 4
Cone element, 43cm loading coil - 2
Aerial fixing screw & washer - 1
Support pipe - 1
Fixing hardware - 2
U-bolt (with nut & washer) - 2
L-shaped allen key - 1
Coaxial cable N/BNC - 1

Operating manual / leaflet

Downloads available in Acrobat PDF format:

DA753G manual / leaflet PDF (94kb)

What is a discone: For wide coverage in the VHF-UHF bands a compromise has to be met and the most popular aerial is a discone (a disk of elements over a cone of elements). Their appearance is like a large spider or umbrella without the covering material, the better models have about 12 to 16 elements... avoid discones with only a few elements (such as six). Typical usable coverage starts from about 25 MHz and extends continuously to 500 MHz, 1300 MHz or even 3000 MHz. The coverage peaks and dips throughout it’s range as the elements interact to provide the widest possible coverage. Due to their necessary construction discone aerials are a little prone to "wind noise" & possible damage in severe gales.

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