WA7MLH OSHPark Share1

Single stage broadband feedback amp
TO-92 & TO-39 case styles
It also has separate base bias control.
Separate bias control is very useful for TX biasing in PA driver stages.


GP_FE General Purpose RX Front End (EMRFD) BF998 Si Dual Gate MOSFET

GP_FE OSHPark Link

HYCAS Hybrid Cascode AGC/IF Amplifier W7ZOI & WA7MLH QST Dec 2007


Original Article

Phase_Freq_Det_DIP Digital Phase Frequency Detector

Phase_Freq_Det_DIP OSHPark Link

7/7 QRP RX superhet from www.w7zoi.net
This design was optimized for low power consumption (approx 30mA on RX) while remaining a true superhet.
Original design by Wes was for 3 xtals. I had enough space to accommodate 5 xtals, making it easier to
design the xtal filter with XLAD xtal filter design that came with early editions of EMRFD.
The XLAD default for Gaussian to -6dB response is for 5 xtals. There is an XLAD08 bug in the k & q values for 3 & 4 xtals.
This superhet will work great up through 10m, and probably 6m. SA612 front end mixer is spec'd at 5dB NF at 45 MHz.
I have built monoband Field Day TXVRs with this design for 40m & 20m with good results.

7slash7 RX3 OSHPark Link

7/7 QRP TX from www.w7zoi.net
This is the matching TX for the 7/7 RX.
Both boards are the same size with matching mounting holes.
My 20m version stacks the boards, which in hindsight was not such a good idea.
Stacked boards makes troubleshooting and mods very tedious, if not outright difficult.
This TX board has additional circuit space for a balanced PA for higher Pout than the design of 1W.

7slash7 TX3 OSHPark Link

Copitts VFO for 7slash7 RX & TX boards.
See www.w7zoi.net for more details

7slash7_VFO OSHPark Link

Direct Conversion RX. Only 2 ICs. This is SMD for all parts.


Downconvert Mixer for One-on-One Tracking PLL.
EMRFD Ch 4.23

Tracking_PLL_MIX OSHPark Link

Breakout for BF998 Si Dual Gate MOSFET
Makes SOT23 BF998 SMD easy to solder wires to for ugly construction

BF998 OSHPark Link

Breakout for BF998 Si Dual Gate MOSFET with DC blocking caps and gate bias resistors.
Makes SOT23 BF998 SMD easy to set up with the most common mixer and gain stage topologies.

DG_Breakout OSHPark Link

Broadband variable gain bench amp.

HYCAS_Bench OSHPark Link

General purpose Colpitts xtal BFO (also xtal osc in general).
This layout supports both HC6 & HC49 xtal cans.
Lots more details in pdf schematic in the dowload zip file.


Temperature compensated voltage controlled oscillator.
Ground plane has been removed under resonant circuitry to minimize drift.
See EMRFD Chap 12.8 for more details.


RF SPDT switch using Skyworks pHEMT switch IC
This will work from 1 MHz through UHF
Control voltage at 3V per gate can be set via resistor divider values.


WA7MLH OSHPark Share2