tiny SCR Preselector  

tiny SCR Preselector

1.8MHz to 30MHz, five bands, tunable Band Pass Filter.

A less complex version of the SCR Preselector.

Software Controlled Radio Preselector via USB or I2C bus. Digital tuning.

Assembled and kit versions.

tiny SCR Preselector is available through

There are no active switching devices in the signal path therefore it does not contribute to IMD (Intermodulation Distortion) itself.

■ Five bands tuneable Band Pass Filter bank for HF Bands covering 1.8 to 30 MHz.
■ Digital tuning.
■ High linearity (IP3). Suitable for Software Define Radios.
■ Removes the strong signals radiated back to the antenna from quadrature
mixers in SDR applications
■ Joined to a VFO can perform tracking tuning function.
■ Its modular design lets an easy implementation on your projects.
■ I2C Bus or USB control modules options.
■ Tin plated enclosure available.
■ Board dimensions: 152mmx75mm( 5.984x2.953in)

USB control option

■ PC controlled through graphical user interface (GUI).
■ Full speed USB v2.0 compliant.
■ Plug and Play feature.
■ Runs under Windows 2K, XP, Vista 32 and Windows 7 OS.
(Windows 2K users need to update Framework from Windows Update site)
■ Board dimensions: 62mmx50mm( 2.441x1.969in)

I2C bus control option

■ 16 bits standard I2C Bus serial bus interface.
■ Support 100Kbits/s and 400kbits/s FAST I2C Bus protocols.
■ Auxiliary Input/Output ports to implement external controls and/or signalling.
■ Up to eight control modules can share the same I2C Bus.
■ Compatible with most microcontrollers.
■ Board dimensions: 70mmx47mm( 2.756x1.85in)

User manual

Assembly manual

I2C bus control module

Project example with tiny SCR Preselector by DJ8OM,Oskar Mayer.
He uses the tiny SCR Preselector with Flex SDR-1000, SDR-IQ and nine versions of SoftRock.

The tiny SCR Preselector should be preferably encloused in a RF tight box due the antenna effect of its large coil that easily gathers nearby signals or noise.
To shield the tiny SCR Preselector against electric and magnetic fields a properly manufactured tin plate enclosure is offer including punched holes for connectors.
Dimensions are: 162x102x50mm. (6.378x4.016x1.969 inch)

Antenna Input/Output By-Pass. Dual relay

It is designed to by-pass any device in line with your transceiver or receiver.
A typical application includes inserting between antenna and transceiver or
receiver a preselector, preamplifier or filter devices.
It is by-passed on transmission switchover (PTT) avoiding being overloaded.


- Frequency range: DC - 60MHz
- Insertion loss: 0.2 dB @ 50 MHz
- Isolation: 60 dB @ 50 MHz
- Power rating: 150 W PEP
- Impedance: 50 Ohm
- SWR: 1.22 @ 50MHz
- Power supply: 12 Volts DC/65 mA
- Switching time:
- Set: 15mS
- Reset: 5mS
- External Dimensions: 40x37x111mm.
- Connectors: SO-239 Transceiver/Antenna; BNC IN/OUT Preselector.
- Set of coaxial tails included.
           

Diagram	Schematic

- tiny SCR Preselector. Band Pass Filter bank module and control module.
- IDC-ribbon interconnection cable.
- USB or I2C control module option.
- USB cable. (USB control module option)
- CD ROM including comprehensive user and assembly manuals, including all software and USB driver for Windows Operate Systems.

- All parts needed to build the kit. Includes pre-progamed PIC microcontroller (USB option)
and pre-winded impedance match transformers.
- IDC-ribbon interconnection cable.
- USB or I2C control module option.
- USB cable. (USB control option)
- CD ROM including comprehensive user and assembly manuals, including all software and USB driver for Windows Operate Systems.

tiny SCR Preselector is available through