Juergen Dahms, DC∅THERE, Brandbruchstr. 17, 44265 Dortmund
A goal of this publication is it, the experimenting microwave amateur in
to give simple concept to the hand, which it with its considerations to
Realization to support is.
During my conversion from the beginning one stood in the foreground: Should admitted and
several times tested building groups to be used. In addition it was to be considered whether not up
already existing housing standards from the microwave engineering of Michael, DB6NT
to be fallen back can.
Thus only slight changes of already well-known concepts became in the final result
necessarily and the expenditure, on this amateur band first experiences new for us too
collect, held themselves temporally and financially within limits.
Of me schematic sketch thought with DB6NT was through-discussed and thanks out the its
Assistance, two new teflon plates once for the receiving mixer and once for the transmitter
Multiplier to sketch, knew the project brought to a successful conclusion
On the basis the first foil the progression for the receiver and the CW- becomes transmitter
The receiving mixer concept corresponds to the 76GHz structure of DB6NT, only those
Mixer plate was again made by DB6NT. The mixer diode must the relatively small
LO- achievement of approx. 3mW on 40GHz treble and over the circular waveguide
arriving input signal of 122GHz on a ZF of 2m down-mix. As diode
a zero bias Detector diode of HP (HSCH 9161) is used. Thus one saves
itself an additional diode pre-loading; this Detectordiode works already with relative
small LO- achievements. A working resistance of approx. became experimental. 100 ohms
determined. With approx. 0,3V voltage drop at this flows through thus a shunt current of 3mA
the diode. With a small Milliampermeter parallel to the resistance thereby those can
Operability of the mixer course during the enterprise to be controlled.
The diode sits mechanically directly over the circular waveguide, therefore the M2 thread may
in the short-circuit block for the M2 screw to down to be cut through not completely.
Crush the diode body by this measure thereby became impossible.
The circular waveguide of 1,7mm diameter, computed by DB6NT, is from that
Frequency transmission dimensions, the unwanted harmonious in such a way ago of the
Transmitter multiplier at the mixture do not arrive (frequency range from 103 to 135GHz,
Center frequency 117GHz). By the selected frequency concept the empfangssystem works
The mixer is operated only as receiving mixer, because of the high mixing losses and
the small LO- achievement here no attempt single-sideband modulation is worthwhile itself too
Over the new semiconductor assembly in the second Doppler from 20 to 40GHz became already
in detail of me in the conference volume of the 26. GHz conference Dorsten, S. 26 29 as well as in
attainable doppler achievement on 40GHz somewhat smaller out than on 38GHz.
The original dimensions of the 76GHz of mixer housing are fully taken over, only
Seat and diameter of the circular waveguide are according to the defaults by those
To consider mixer plate again.
The ZF- preamplifier became inviduell from me on a small suitable raster plate
(Vero board) with a BFP 182 developed (after collecting main of the circuit of the new ZFPlatine
for the 47GHz mixer of DB6NT).
With the CW- transmitter I selected the fastest kind of realization. Is used here
however not the well-known 12GHz LO- plate separates one from it from DB6NT
developed 24GHz version on teflon base material. Depending upon used multiplier diode
(consider max. input wattage!) becomes more changed either in the drain resistances
24GHz preamplifier (to approx. 50mW power output with approx. 0,5mW input wattage) also
3 time NE 32584C or the 24GHz Pa component (up to 120mW power output with approx.. 1
to 3mW input wattage) with 5 times NE 32584C, both components of DB6NT,
connected at the outlet side.
The actual multiplier of DB6NT is sufficiently well-known. The 24,4GHz becomes after
122GHz verfuenffacht - this surely results in a better efficiency than in the case of that
admitted often applied sixfold increase after 145GHz with the structure of a 145GHz
Throttle line at the entrance (in place of for 40 now for 24GHz) and the coaxial entrance
in place of the pin linking for waveguides. For the seat of the diode on the plate directly over
the circular waveguide applies with the receiving mixer described the already to consider.
With my first experimental setup I have the Russian Varactordiode A 92220-1 (30mW
Input wattage, old designation 3A643 C3) assigned.
Surely this frequency pattern looks by far more badly than with the receiving mixer.
The round hollow pus becomes a large portion of the quadruple frequency of 24,4GHz (about
98GHz) still let through, but we all know, how difficult it is still at present, achievement
to produce on 40 or even on 60GHz. The receiving mixer can do however those
Frequency of 98GHz do not process.
No changes are also here to up to seat and diameter of the circular waveguide
Standard housing of DB6NT necessarily.
The supply voltage of the 24GHz of amplifier can for CW- enterprise as admits
click-free with a BUZ 171 o. ae. to be groped.
The second foil illustrates schematically the CW- transmitter course as well as that
Receiving mixer, both in each case without the still pertinent oscillator components.
With 2m ZF a quartz with F = 127,344MHz becomes, for the LO of the RX in the LO for the TX
Quartz with F = 105,995MHz needs. It should be absolutely worked with OCXO‘s!
Although two useful 145GHz is present parabolic reflectors, I could do still none
Radio communication on the 122GHz volume transact, there so far still another radio partner with one
is missing to second station.
The developed components went therefore at Karl, DJ6BU, there his radio partner walter,
DH6FAE likewise a concept considers. Like that here expressive field tests are in more details
To expect future.
My thanks apply for Michael, DB6NT to the preparation of the plates.
Michael becomes the two new plates (“RX mixer” and “Multiplier by 5”) in its plate
Utility routine also take up!
Since some microwaves are quite amateurs by means of commercial modules able,
on 40GHz achievement to produce, becomes Michael likewise an appropriate plate for one
Three-way 40/120GHz in its program offer.
I hope with my short contribution something taste for experiments on the 122GHz
Volume to have produced.
73+ 55 of DC0DA, Juergen
CW- TX 24 GHz LO- DB6NT (Q = 127 MHz)
P = 5 mW
F = 24,5 GHz
24 GHz Pa DB6NT
P = 100 mW
Multiplier (× 5) - DB6NT
F = 122,250 GHz
Mixer RX 10 GHz LO- beacon DB6NT (Q = 106 MHz)
P = 30 mW
F = 10,2 GHz
24 GHz Doppler DB6NT (12/24 GHz)
P = 20 mW
F = 20,4 GHz
38 GHz Doppler DB6NT (19/38 GHz)
P = 3 mW
F = 40,8 GHz
145 GHz mixer DB6NT
Zero bias Detector diode
ZF = 144 MHz
Three-way and mixers
Parabol 145 GHz PROCOM mirror with HL WR7 (110 170 GHz)
DB6NT- LO “24GHz”
DB6NT- LO “10GHz”
×2 ×2 ×3
Block diagram of the transmitter and the receiving mixer for
CW-TX with round HL- horn antenna and RX- mixer with mirror pick-up flange
(both building groups without oscillator component)
Receiving mixer with opened HF side
(1.Doppler 10/20GHz, 2.Doppler 20/40GHz, mixer m. short-circuit block)
To fig. 1: 7,7cm Ø centric precision mirror as reference antenna (
122GHz 35dBD profit)
To fig. 2: Self-‘s building slave station with 45cm Ø offset mirrors and
Illuminating by means of groove horn (50.3 dBD profit)
To fig. 3: Slave station with better representation groove horn of the emitter
To fig. 4: Beacon transmitter with round HL- horn antenna in the open area
To fig. 5: Test area in the riser forest in the proximity of the city Fulda
Result: With a distance of scarcely 1km was the empfangsfeldstaerke
the beacon signal approx.. 45 railways over noise levels, determined also
Precision absorption member of HP, adjustably in 10dB steps.
Receiving became with the offset mirror.
Pictures and text taken over from a written interim report of
Further attempts with approx. 1,5km distance with consideration that
different air humidity are intended.
73 de DCØDA