144MHz-146MHz to 28MHz-30MHz VHF down converter for SDR radios.

Compatible with any analogue radio or Software Define Radios. (SDR)



The Heros Tech 144-146MHz to 28-30MHz VHF Down Converter introduced here expands the frequency range of any Software Define Radio (SDR) or analogue shortwave receivers covering 28MHz to 30MHz (10m band) allowing reception of the exciting 144MHz-146MHz band (2m band).

The Converter is connected between the antenna and a SDR or analogue HF radio (called IF receiver).

When turned ON the 144MHz-146MHz band is mirrored on 28MHz-30MHz band. For example, if the IF receiver is tuned on 28.430 MHz, you are receiving the frequency of 144.430 MHz, (allocated segment of frequencies for beacons according to the 2m band plan in some countries.) Tuning to 29MHz you are receiving 145MHz and so on. Some SDR software, as PowerSDR, provides the capability of configure the LO off-set frequency in order to update the dial readings. (see below "Connection to FlexRadios diagram)

The Converter allows the reception of all amateur radio services assigned to the 2m band such as SSB, CW, FM, RTTY, FAX transmission modes, internet voice gateway, digital communications, repeaters space communications, (ISS International Space Station, space-Earth link), amateur satellites and many more stimulating activities.

The Heros Tech 144-146MHz to 28-30MHz VHF Down Converter is designed taken in account the wide range of signal variability that are expected to be received. Those conditions demand for very low noise, good front end filtering, high dynamic range performance, excellent IMD characteristics and good IF receiver isolation.




Technical specifications:

Compatible with any kind of radios Analogue and SDR.

Converter class: Superheterodyne. IF output mirrored down

Frequency range: 144MHz-146MHz (2m amateur band).

IF output: 28MHz - 30MHz.

Input/Output impedance: 50 Ω

VHF Front-End preselector:
ESD protection on antenna input.
FM broadcast band rejection filtering.
Dual high dinamic range E-PHEMT preamplifier.
Gain: 38dB. Noise figure: 0.5dB.
Dual 144MHz-146MHz helycal filter.
Seven poles Elliptic Low Pass Filter.

High L-R/L-I ports isolation double balanced mixer.

Local Crystal oscillator:
High stability, very low jitter, 116MHz synthetised crystal oscillator.

IF output:
Frequency: 28MHz-30MHz.
28MHz-30MHz Band Pass Filter.
80dB high isolation IF amplifier.
0dB-15dB variable gain range. User regulable.

-Power supply: 12volts/350mA

-Enclosure: Aluminium

Size: 165mmx80mx45mm ( 6.5x3.15x1.78in)

Diagram   Manual

2m band converter diagram.
(click on icon to enlarge)

  2m band converter manual.

Front panel.   Rear panel.

Connection to a generic SDR radio.   Connection to a generic analogue radio.

Connection to FlexRadios
(click on picture to enlarge)

Optional Accessories


General purpose LF-HF-VHF-UHF, Dual Port, by-Pass relay

100 Watts RF power rating

DC - 1300MHz

It is designed to by-pass the Input and Output RF ports of any device in line with your transceiver or transmitter
A typical application includes inserting between antenna and a transceiver or transmitter a preselector, preamplifier or filter device.

On transmission switchover, via PTT or Keying line, the Input and Output RF ports of the device are by-passed avoiding being overloaded.




0 - 71 dB Step Attenuator Ladder Configuration

The step attenuator is suitable for receiver front-end protection or as calibrated attenuator for receiving performance evaluation.
It is an inestimable tool for accurate control of amplitude levels.
In addition, it improves the impedance match between impedance-sensitive devices, such as amplifiers, oscillators and filters, lowering the VSWR of components connected in cascaded mode by providing isolation between the impedances




VHF-UHF-SHF Antenna Galvanic Isolator. 20MHz-1.2GHz

Removes local pick-up noise by the antenna feedline.

Specifically recommended to work with SDR radios.
Suitable for analogue radios.
Indoor mount.



  VHF Down-Converter Price    

Input: 144MHz-146MHz

IF output: 28MHz-30MHz.. ; SKU: HS-1145V

£ 220.00 SCR Preselector-CAT  
  The set includes:
VHF Down-Converter, user manual in CDROM format, two BNC-BNC coaxial cable tails, power supply cable with EMI filter and auxiliary connectors.