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dominicbeesley · 1st Dec 2009, 11:32 am

Well done!

Winding coils used to always scare the stuffing out of me too until I had a go. So far like you I've (nearly) always been pleasantly surprised - and its not a big deal to start again!

The real difficuly on a superhet is getting the tracking right i.e. the oscillator circuit to stay precisely the IF (455kHz) away from the RF circuit.

This can be checked roughly by getting it working at one end of the scale then tuning to the other end and adjusting the padder to line it up then check it works well all the way through the range....or you could do what I did and have a seperate tuning condenser for RF and oscillator but then you need extra arms!

Dom

1st Dec 2009, 11:32 am	#2
dominicbeesley Octode Join Date: Nov 2004 Location: Hebden Bridge, West Yorkshire, UK. Posts: 1,885	Re: Mixer LO/Tuning coil progress. Well done! Winding coils used to always scare the stuffing out of me too until I had a go. So far like you I've (nearly) always been pleasantly surprised - and its not a big deal to start again! The real difficuly on a superhet is getting the tracking right i.e. the oscillator circuit to stay precisely the IF (455kHz) away from the RF circuit. This can be checked roughly by getting it working at one end of the scale then tuning to the other end and adjusting the padder to line it up then check it works well all the way through the range....or you could do what I did and have a seperate tuning condenser for RF and oscillator but then you need extra arms! Dom