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)
1.5 – 32 MHz
See table above
400 Watt average, 1600 Watt peak
Less than 0.3 dB
Less than 1.2:1 (2 – 30 MHz), Less than 1.3:1 (1.5 – 32 MHz)
Greater than 26 dB
‘N’ type (Others on request)
Alumina ceramic M6 thread
-40ºC to +55ºC
High voltage protection:
Arcing horns and internal static drain (NB No internal capacitors fitted.)
Cast aluminium case (LM25). Hermetically sealed. Epoxy paint finish.