Hi,

Further to my e-mail, having seen the schematic now, it
is probably the antenna which is screwing things up.

Firstly, take the antenna off the collector of the
oscillator and either link-couple it (a couple of turns
with one end grounded) or tap it down the tank coil till
the oscillator starts reliably. You are not looking for an
exact match here but a way of coupling energy more
efficiently into the antenna without the oscillator
thinking that it's his mother.

Secondly, the base biassing you have on the oscillator
is too dependent on individual transistor parameters. I
suggest that you connect the base to ground through another
10K and then adjust the emitter resistor until you have 5
to 10 mA flowing through it. You can tell when you have it
about right by measuring the voltage across it. Touching
the circuit near the coil with your finger should also show
some variation in voltage if the circuit is oscillating.

Finally, you appear to be relying on the battery for an
RF return circuit which is not good. Try placing a
capacitor of about 0.01uF between the supply and ground,
close in to the oscillator.


Cheers - Joe