143MHz-146MHz to 27MHz-30MHz VHF down converter.


Compatible with Software Define Radios (SDR) and analogue radios.


New extended radio spectrum coverage!

Covering space surveillance and 2m VHF amateur radio band.


The Heros Tech 143MHz-146MHz to 27MHz-30MHz VHF Down Converter introduced here expands the frequency range of any Software Define Radio (SDR) or analogue shortwave receivers covering 27MHz to 30MHz (11m-10m bands) allowing reception of the exciting 143MHz-146MHz band (Space Surveillance and 2m band).

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

When turned ON the 143MHz-146MHz radio spectrum is mirrored on 27MHz-30MHz. 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 example)

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 surveillance and communications, (Meteors and satellites detection, ISS International Space Station, space-Earth link), amateur radio satellites and many more stimulating activities.

The Heros Tech 143-146MHz to 27-30MHz 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.



Space Surveillance of objects entering the atmosfere on 143.050 MHz


The Heros Technology 143-146MHz to 27-30MHz VHF Down Converter connected to a SDR radio lets to receive reflected signals from the French G.R.A.V.E.S. powerful radar beam on 143.050MHz in order to listen and visualise to reflections on meteor showers, planes, spacecraft, low orbit space objects, bounced signals on the moon,tracking satellites and UFOs....?


Moon bounced signals from G.R.A.V.E.S. radar received in Argentina.



Technical specifications:

Compatible with any kind of SDR radios and Analogue radios.

Converter class: Superheterodyne. IF output mirrored down.

Extended frequency range: 143MHz-146MHz
(Space Surveillance and 2m amateur band).

IF output: 27MHz - 30MHz. (11m-10m bands)

Input and 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 143MHz-146MHz helycal filter.
Seven poles Elliptic Low Pass Filter.

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

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

IF output:
Frequency: 27MHz-30MHz.
27MHz-30MHz Band Pass Filter.
IF amplifier:
80dB Output- Input isolation .
0dB-15dB range variable gain by user..

Power supply: 12volts/350mA

Enclosure: Aluminium

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



VHF down converter diagram.


VHF converter_brochure

Front panel.   Rear panel.

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

Connection to SDR FlexRadios
(click on picture to enlarge)

Optional Accessories


General Purpose Dual Port Signal Relay. DC - 1300MHz

100 Watts RF power rating.

Typical applications include:
Inserting between antenna and a transceiver or transmitter a Converter, Preselector, Preamplifier, Filters, etc.
On transmission switchover, via PTT or Keying line, the Input and Output RF ports of the connected device are by-passed avoiding being overloaded.

Other applications let to configure working with two antennas and one or two radios, static protection against electromagnetic pulse (EMP) especially on stormy weather situations and other configurations involving RF signal switching.


10kHz - 150MHz LF-HF-VHF Antenna Galvanic Isolator.

Hi-Power rating: 200 watts continuous wave.(400watts PEP)

Removes local pick-up noise by the antenna feedline.

Specifically recommended to work with SDR radios.

Suitable for analogue radios.

Indoor mount.




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

Power rating: Reception

Removes local pick-up noise by the antenna feedline.

Specifically recommended to work with SDR radios.

Suitable for analogue radios.

Indoor mount.


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.


  143MHz-146MHz to 27MHz-30MHz VHF down converter Price    

Input: 143MHz-146MHz

IF output: 27MHz-30MHz.. ; SKU: HS-1145V

£ 252.00 SCR Preselector-CAT  
  The set includes:
VHF Down-Converter, user manual in CDROM format, BNC-BNC coaxial cable tail, power supply cable with EMI filter.