Boards for Sale

UHFSDR 995x BPF 100W LPF 1.5KW Diplexer HSUSB Si570



995x Parts Group Buy







Kit assembly is now available.

Contact Chris at < kd4pbj@gmail.com> www.smt-solutions.net >


1.5KW Diplexer Filter

(5-11-12). Production boards are on hand. More Details

RF amplifiers require low pass filters to get rid of harminics. This series of boards will provide a low pass filter to block the harmonics from getting to the antenna, and a high pass filter to route the harmonics to a 50 ohm "dump" resister. Each section is a 7 pole Chebychev low pass and 7 section high pass filter. Unlike a low pass only filter, this filter presents a good match to the amplifier at all frequencies. The boards are approximately 8" by 2" on .126" FR4 with 2oz copper for each band.

1.5 KW Diplexer PCB USA $13.00  

1.5 KW Diplexer PCB Outside USA $17.00


100W Low Pass Filter Board


The board contains 7 relay switched 5 pole low pass filters.

Circuitry is provided for control via a I2C bus connection.

Test points are provided for manual operation. The board is 3.0" by 7.2 ".

Download Schematic, PCB Layout ,BOM, or Assembly Manual

Production boards and kits(PCB and Parts, no case) available now. .






The USBI2C is a small(1" by 1-3/8") board designed to provide USB control of SDR radioes that use the Si570. The board will plug into H1 on the UHFSDR or H2 on the Si570 boards. Firmware was written by PEOFKO originally for the softrocks.


PCB Layout

USBI2C for USA Delivery


USBI2C for outside USA Delivery



The UHFSDR is a Software Defined Transceiver covering the 1.75 MHz to 700 MHz frequency range. A Si570 is used for frequency control. Two LVPECL 4 GHz max.flip flops produce I and Q LO signals at 1/2 the Si570 frequency. A pair of 1-1000MHz Double Balanced Mixers are used to convert signals to and from base band. A receiver pre-amp (2dB noise figure) and a transmit pre-amp(50mW max output) are provided as well as antennal switching plus provision for separate receive and transmit connections. For additional information, download the Assembly Manual. The BOM, schematic, and board layout are Here. A HiRes(3.7MByte>) picture of the completed board is Here . A plug in USB interface(USBI2C) is now available.

Dave Miller-VE7PKE and the AQRP group are working on a board with a LCD and an STM32F4 ARM processor to replace the PC. Info at STM32-sdr .


UHFSDR Yahoo Group



I am offering a Mini-Kit containing the mixers, RF transformers, rec and tx mmic amps, rf switches, and the ADuM1251. The PCB is NOT included.

A spreadsheet with the remainder of the parts needed(except the Si570) for upload to Digikey is here

A CSV text file with the remainder of the parts needed(except the Si570) for cut-paste to Farnell is here.

The Si570 may be ordered at

< http://www.silabs.com/products/clocksoscillators/Pages/utilityintro.aspx >

In Europe the Si570 may be ordered from





Click to join UHFSDR

Click to join UHFSDR

PCB USA $10.00

PCB Outside USA $14.00



Mini-Kit USA $40.00

Mini-Kit Outside USA $45.00



Si570 Board


A 1" by 1.35" circuit board has been designed for the Si570 programmable crystal oscillator chip. The board contains the Si570(NOT included in kit), a 3.3V regulator, a bidrectional level shifter for the I2C inputs, an optional droppoing resister(for 12V use),sma outputs, and headers for I2C control, power input, VCXO control(used on Si571 only), The board will also work with other oscillators in the standard 5 X 7 can.

For documentation go here

The parts kits contain the following:

2 - 10uF; 3 - .1uF; 3 - .01uF; 1 - 200K; 2 - 49.9; 4 - 1K; 1 - GTL2002; 1 - LP2992AIM-3.3V, PCB


Si570 Kit USA $9.00
Si570 Kit Outside USA $13.00





Board Front

The AD995x board contains a USB controller, a DDS(AD9951, AD9952, AD9953, or AD9954), a quadrature generator, and a Quad Sampling Detector(QSD). By populating appropriate parts of the board the board may be used for the following:VLF to VHF signal generator with programmable output power. Receiver covering at least VLF to 54MHz or above with connection to a suitable PC and soundcard. The addition of the BPF Board(controllable from the PIC controller) provides a complete receiver. Receiver and transceiver VFO with quadrature generation and receiver control.Spectrum Analyzer with tracking generatorVNA(requires slight modification of the QSD circuit to provide DC coupling). For a full description of the operation of the board click on left.

For a discussion of this board and associated software being developed join the DDS_Controller Group .

Discussion group for a group buy of parts for the 995x board is here .

Parts list for 995x-R1 here

Parts list for 995x-R3 here

. I have included values for 3 different LPF designs depending on the clock frequency used. Uncheck the values for L1,L2 and L3 as well as C26-C32 for the LPF freq. you are not using.


995x_PCB  For USA Delivery

$9.00 each

995x_PCB For Outside USA

$13.00 each  



Band Pass Filter

BPF Front

The BPF board contains 6 Band Pass Filters.  Each can be up to 7 element Cheb.  or elliptic in complexity.  Coils can be any size from 0603 to 1810.  The schematic shows my design for six 7 element filters designed for a general coverage receiver from 1.8 to 30 MHz.  The filters are selected by 3 CMOS control lines.   In addition, the board has transformer input and the control and RF grounds are joined at a single point. 

Click on BPF Board on left for board design documentation and engineering measurement made on the board.

BPF_PCB For USA Delivery

$9.00 each

BPF_PCB For Outside USA  

$13.00 each






High Speed USB Interface

HSUSB Board Info

Production boards and kits are now available.

This board was part of the Software Defined Transceiver. A Cypress CY7C68013A provides a high speed (480Mbps) USB 2.0 interface and an 8051compatable microprocessor. The design has been ported over KICAD. This would be a good board to use with 192 KHz A/D and D/A converters. High speed USB 2.0 is specified as 40 times faster than "full speed" USB 2.0 that is in the PIC USB devices. These boards are also compatable with the N2PK VNA.

Bare PCB

USA $8

Outside USA $12


Basic Parts(except CY7C68013A and headers and PCB)

USA $10

Outside USA $14

Headers + Matching Plugs

USA $22
Outside USA $27


USA $16
Outside USA $20