30a) Transmitters, Lo40K39a/d
> modulators <click here>

Links to other pages:
30b 2nd part Lo40K39 tx (Modulators)
30e S10K/L transmitters
30m 80W.S.a transmitter
k91 Correspondence concerning radio communication at Batt. Vara
Betr.: Funkverkehr zw. den Batt. "Hanstholm II" und "Vara"

Lorenz Lo6K39, Lo6L39 receivers, see 24L.

Power cable for Lo40K39

S 39653 (Lo40K39). Type plate.

Lo40K39/S 39653 seen from different angles

3x RL12P35

Lorenz Lo40K39a and d:

Type plates for Lo40K39d (S23725/I ) and S18205/III (Lo40K39a)

S18205/III (Lo40K39a) front plate and scale removed

S18205/III (Lo40K39a) seen from above

Lo40K39d (S23725/I) seen from above

S18205/III (Lo40K39a) rear view, note the "different" switch to the left and the extra capacitor below.

Lo40K39d rear view. Note the coil and the larger switch to the left

S18205/III (Lo40K39a) seen from below. Note the power connector below/behind the valve sockets.
The chassises seem to be equal and it is an empty space for power connector on the lower left side.

Lo40K39d seen from below. Note the power connector to the right

The two models are quite different, the antenne coupler is different, the power connector (flat contacts) may be
supposed to plug into a socket when the unit is installed in a box.. The S18205/III (Lo40K39a) is a wreck, almost
all drives are stuck, and a large job must be done, but - as always the worst part is to find a way to dismantle the parts
without breaking anything. It seems that Lo40K39d is operational, as it was when I swapped it for a TS500 in 1976.
While the reason for LA3WU for giving me the other set was that it was some problems concerned.
Lo40K39a (S18205/III) 5,0-16,6MHz - without match coil for 8m antenna
Lo40K39d (S23725/I ) 3,0-16,6MHz

Lo40K39a has power connector with flat contacts behind the 2x RL12P35.

See also LA6NCA's notes for Lo40K39d (you can identify his set from the antenna tuner switch and coil)

Power supply for Lo40K39 with built-in modulator (RV12P2000), this is a quite unusual version.
The unit belongs to LA6NCA

RG12D60 Rectifier valve for SGLE0,2/2R Netzanschlußgerät

Die deutschen Funknachrichtenanlagen bis 1945, Band 2 [Fritz Trenkle] pp.196 and 219.

More info for 40 Watt Kleinsender Lorenz and many other
Seefunk+Seeschiffahrt  (Seefunk Fotos/TX Seefunk Sender)

It was usually a problem that Lo40K39 wouldn't give pure T9 tone, so often S10L(FuG10 series)
transmitter was operated on lower voltages and used as a VFO for Lo40K39 (for amateur radio)

Lo40K39d Technical data

VFO: RL12P35, PA: 2x RL12P35

Power supply requirement

H = 12,6VAC 2A
A1 = +600V 40mA
A2 = +800V 150mA
Sg1 = +150V 20mA
SG2 = +200V 48mA
G1 = -260V
G2 = -245V

AC Mains current max 2.1A
Power output with SGLE0.17/2 = 40W telegrafi overcurrent in antenna-circuit
Power output with SGLE0.2/2 = 70W telegrafi overcurrent in antenna-circuit
Frequency 18-100m (3000-16667kHz)
Bereich I : 9200-16667kHz - range I
Bereich II : 5000-9300kHz - range II
Bereich III: 3000-5200kHz - range III

Antenna: Single wire antenna, 8-12m length

Component list:
Pos type electrical value
1 valve RL12P35
2 variometer (note..)
3 capacitor 71cm 3kV
3a capacitor 100cm (110pF?)
3b decoupling cap 180cm (200pF?)
4 anode choke 140 turns 0.4mm cu ss
5 coupling cap 5000cm
6 capacitor 5000cm
7 grid block cap 250cm
8 capacitor 5000cm
9 capacitor 5000cm
10 Bereich schalter 3x3 pos
11 resistor 20 ohm
12 resistor 20k
13 grid choke L=0.30mH, R=0,41 ohm
14 capacitor 1000cm (1000pF 2400V)

15, 16 valves RL12P35
17 tuningcapacitor C=62cm, 3kVA
18 decoupling cap. C=170cm 3kVA
19 capacitor 500cm 0,5kVA
20 variometer as pos 2
21 switch 1x6 pos
22 anode choke as pos 4
23 neutralizing capacitor
24 capacitor C=5000cm
25 capacitor C=5000cm
26 Resistor 20 ohm
27 Resistor 20 ohm
28 anode coupl cap.C=5000cm
29 resistor 100 ohm
30 capacitor C=5000cm
31 range switch 3x 3 pos
32 anode current mtr 0-200mA
33 grid block cap C=2cm
33a decoupl cap 7cm (2x vorhanden)
Antenna tuner
34 capacitor C=70 cm 3kVA
35 capacitor C=40cm, 3kVA
36 ant range sw 5x 6 pos
37 antenne current meter 1000 ohm resistance, 0-10 positions, measuring range 0-3A,
37c RF measure circuit 3A @18-100m wavelength (for pos 37)
38 antenna series coil 7 taps

believe 1cm =1,1pF
details written as mentioned, but some values seems to be wrong, also some explanations
are silly (not important for the post-war army!). pos 2 has a note I don't understand
(Translated from Norwegian 2000.04.19 LA8AK)


Lo40K39a. Schaltbild des Senders nach St 510563

Lo40K39d. Schaltbild des Senders nach St 513503, Ausg. 5

The Junker key