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

■ Five bands tuneable Band Pass Filter bank for HF Bands covering 1.8 to 30 MHz.
■ Passive filters.
■ There are no active switching or amplifier devices in the signal path therefore it does not contribute to IMD (Intermodulation Distortion).
■ Removes strong signals radiated back to the antenna from SDR quadrature mixers.
■ Digital tuning. Eight bits digital variable capacitor.
■ High linearity (IP3). Suitable for Software Define Radios and analog radios.
■ Tuning coil wound on large toroidal T-200 core, avoiding saturation in front of large signals.
■ I2C Bus or USB control modules options.
■ Locked to a radio performs tracking tuning function.
■ Its modular design lets an easy implementation on your projects.
■ Power supply: 12Volts DC/ 0.250Amp max.
■ 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

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.

The follwing pictures show the tiny SCR preselector assembled on metallic enclosure from Hammond model 1455T1601, available on most electronic stores.

Dimensions are: 160mm X 160mm X 51mm. (6.29 x 6.29 x 2 inch)

USB bus control assembly example.

I2C bus control assembly example.

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.

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.
           

Dual Antenna Relay page

Tiny SCR Preselector - Flexwire I2C bus interconnection cable
(Shielded, EMI protectection)

Diagram.

- tiny SCR Preselector. Band Pass Filter bank module and control module.
- IDC-ribbon interconnection cable.
- USB or I2C control module.
- 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