Communication Technical Services

HF4 Series 400 Watt HF Wide Band Antenna Matching Transformer

HF4 Series
Fixed station HF receiving arrays are often subjected to high voltages not normally associated with RX systems. These voltages can be present due to static build up or by lightning induced EMF’s from nearby strikes.

The HF4 Series of matching transformers, although designed for 400 Watt average power are ideal for inclusion in receiving arrays. They reduce the possibility of high voltage damage and provide a DC path to the ground which gives added protection to the receiving system.

  • Wide band 1.5 to 32 MHz
  • Ideal for fixed station receiving arrays
  • Internal static drain ground

A wide selection of balance and unbalance impedance ratios are available to complement most antenna configurations and non-standard ratios can be supplied on request.

The transformers are housed in cast aluminium cases, fully hermetically sealed for any military or commercial environment. For EMP proof operation no capacitors are incorporated.

HF4 Dimensional Drawing

 

Type Designations for HF4 Series and Technical Specification

Balance Impedance (ohm)
Unbalanced impedance (ohm)
50
75
200
300
370
450
600
50
HF4-55
HF4-57
HF4-520
HF4-530
HF4-537
HF4-545
HF4-560
75
HF4-75
HF4-77
HF4-720
HF4-730
HF4-737
HF4-745
HF4-760

 

Frequency: 1.5 – 32 MHz
Impedance: See table above
Power: 400 Watt average, 1600 Watt peak
Insertion loss: Less than 0.3 dB
VSWR: Less than 1.2:1 (2 – 30 MHz), Less than 1.3:1 (1.5 – 32 MHz)
Balance ratio: Greater than 26 dB
Load VSWR: 2.5:1 max.
Coaxial connectors: ‘N’ type (Others on request)
Balance terminals: Alumina ceramic M6 thread
Temperature range:  -40ºC to +55ºC
Weight: 1.2kg gross
High voltage protection: Arcing horns and internal static drain (NB No internal capacitors fitted.)
Configuration: Cast aluminium case (LM25). Hermetically sealed. Epoxy paint finish.
Shipping dimensions: 220 x 150 x 120 mm approx.
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