This simple to construct project uses a PCB designed by Mike (G0MJW); the circuit consists of an amplifier and mixer with filtering on the input and output. While I have used the board for 4 metres; it is possible to use the same board for other frequencies with adjustment of component values. BATC members can purchase this PCB from the BATC shop. Circuit details can be found here.
For this project I have used one of the Chinese ADF4351 boards to produce a local oscillator at 400MHz. The 4 metre input at 71MHz is mixed up to 471MHz and the output fed to a MiniTiouner.
Another board available at the BATC shop is used for the PIC which sets up the ADF4351 output frequency and RF level. The board designed by Ron (G7DOE) will fit on top of the square Chinese ADF4351 boards. For this project I used the darker rectangular ADF4351 board so mounted the PIC Controller board on a small sub panel. You can see the board in the pictures below here. Code for the PIC is available on the BATC WIKI.
Local oscillator level for the mixer is specified as +7dBm but I found the +5dBm output from the ADF4351 board to be just perfect.
Builders have the option to use the mixer board with or without the PGA-103 MMIC amplifier, I included it on my board as I have no external antenna amplifier.
Below are some pictures taken during the build. The LED on the front panel is connected to the PIC board and illuminates on PLL lock.
See here the PIC Controller board top right; temporary wiring is in place to check that oscillator frequency and output levels were correct.
This picture was taken during a test prior to final assembly; note the hi-tech tinned copper wire antenna.
Now with all the plumbing and connectors in place. To the left of the PIC Controller board is a Chinese buck converter which I used to lower the input volts to a 5 volt linear regulator. This is only for the ADF4351 board as the mixer board will accept 7 to 15 volts DC.
The finished item with not so posh labels; it works a treat so I'm not too bothered about looks.
Lastly a screen grab of the output.