Advanced Projects

The Beer and Stout

The Beer is a direct conversion receiver for the 20 - 80m bands where the local oscillator is generated by mixing the VFO with a band dependent crystal. This gives the same incremental tuning scale for all bands, improves frequency stability and avoids chirp when transmitting! The VFO runs at 1.8 - 2 MHz, with Main and Fine tuning for the desired offset; the VFO output is subtracted from a crystal oscillator which runs 2 MHz higher than the bottom band edge. This LO mixer uses another SA612 and is followed by its own set of bandpass filters. The RX has double tuned RF bandpass filters followed by an adjustable front panel controlled RF amplifier, followed by the SA612 product detector and the main audio amplifier. This feeds the switch selected humped low pass CW filter centred on 725 Hz. The AF gain control drives the audio power amp and is suitable for a speaker or phones. The main PCB has double tuned filters for any two bands (in 20-80m group) fitted to the 100 x 160 mm PCB with DC control of the MOSFETs that select the required filters and active crystal. The kit includes a plain undrilled single sided PCB for your own design of front panel. The price of the Beer for any two bands in the 20 - 80m group is GBP 55. If you wish to make the Beer do all four bands, you need to add a few extra parts to the main PCB as well as the Quad BPF kit which is 50 x 80 mm. The cost of these extras is GBP 25.

The Stout is the associated nominal 5W CW transmitter. It has a big upright heatsink for the IRF510 output stage with relay selected Low Pass Filters for any two bands in the 20 - 80m group. It is driven by the local oscillator signal from the Beer RX. Both the RF output power and sidetone level are front panel adjustable. Electronic full break in operation is provided which automatically removes the receiver's Fine tuning offset so that it transmits on the other station's frequency. The two band Stout price is GBP 25.  To make the Stout do all four bands, apart from needing all four in the Beer, you need to add the Dual Low Pass Filter kit which costs GBP 14 if bought on its own.

The price for an any two band Beer and Stout is discounted to GBP 79; the Four band Beer & Stout is also reduced to GBP 110.

The picture below shows a two band version with the empty 'quarter' waiting for addition of the Quad BPF and Dual LPF for the two extra bands to make it into a four band version.

 

Somerton and Dorchester

I am working steadily on the design of the new Somerton Receiver and the associated Dorchester Transmitter. Enthusiasts will know these two places as the historic sites for the early overseas 'beam' radio stations built by Marconi in 1927. Somerton is just down the road from here! It is proving challenging to obtain a cost effective design! News of their progress will be reported in Hot Iron.


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