I've looked at the aluminium boxes which look great for most
projects but I want something a bit stronger and professional
looking for the transceiver. Maplin also sell the Hammond range of
enclosures but their biggest is too small. Since posting I have
found a bigger range of the same style at Rapid Electronics and I
may go for one of these.

I'm pretty excited about building the BITX20A, my plan is to use an
LCD display using a 10 turn pot/varicap diode instead of a tuning
cap and I aim to bring the cost in at under £100.
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Charlie , When replacing a variable aircap by a 10turn potmeter +
varicap , I would suggest you pay much attention to the stabilised
voltage feeding the potmeter/varicap ,to ensure acceptable frequency
stability