Simple micro transmitter

[Murphyv310]

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Hi. above is the 3 valve version that I have settled on as my final TX.
The components are as follows:
C1, 10nf
C2, 10nf
C3, 100nf
C4, 500pf
C5, 100uf ***
C6, 10uf ***
C7, 1nf
C8, 47nf
T1, Trimmer 5-50pf
VC1, 200pf
VC2, 100pf +++ see text
D1 & D2 +++ see text
L1, 0.18mh
L2, 0.47mh
L3, 0.82mh
L4 see text
R1, 4.7m
R2, 120k
R3, 39r
R4, 1.5m
R5, 33r
R6, 4.7m
R7, 1.5m
R8, 2x 4.7r in series
R9, 47k
Rx See text
B1 1.2v NI-Mh
B2, 1.5 Zinc carbon.
V1, EM-7
V2, 1ж42a
V3, 1ж18b

None of the values are critical, if the grid resistor on the RF oscillator goes too low the oscillator stops, best not to go below 1.5m.
The Diodes D1 & D2 are only for protection and can be left out, C5 & C6 I found were a good idea if using cheap PP3 and older Ni-Mh batteries as they can be noisy. The value of VC2 may need to be altered as could VC1, both are dependent on the tank coil L4 which needs around 80 turns on a 12 mm former of 18 swg enamelled copper wire, an old MW coil off a ferrite rod works well here.
RX can be used to fine tune the filaments, a small 5 ohm pot is ideal here but not necessary, The filament resistors R3,4,8 may need fiddling with for the voltage to be on the middle of the spec of each valve, don't let the volts drop too low or above the max as the valves life will be shortened.
A small regulated PSU might not be a bad idea though.
Any questions just ask.

Finally T1 should be adjusted for maximum op.