10_________ MHz Transverter, _______MHz IF, Serial Number ________
Power Out: >3W adjustable LP version: > 10 mW
Noise Figure and Gain: <1.5dB @ 17dB G <3.5dB
DC Power Requirement: 10 - 15.5 VDC @ 2.5 Amp <0.6 Amp
IF Option: Common Split
IF Drive Level Requirement: 1-250 mW 250mW-3W 3-10W Other_____________
Keying Option: PTT - to ground TTL - Positive Voltage
Aux. Connection Output Option: TX RX High Low RVD
Antenna Option: Common Separate TX & RX
10 MHz source Internal External
Operational Overview
The DEM 10368-144 is a 3 cm to 144 MHz transmit and receive converter. It has a linear
output power of >3 watts (>10mW for LP version) and may be achieved with as little as 10mW or a
maximum of 10 W of IF drive with the correct IF configuration. The receive section is a design
using a PHEMT LNA (GaAs MMIC in the LP) The base local oscillator frequency is provided by our
A32 synthesizer. It is either configured with an external or internal 10 MHz clock. The DEM
10368-144 has a built in transmit / receive relay driver to provide voltages required by common
SMA relays and provisions for external switching so adding a high power amplifier or preamplifier
to your 5cm system is easy. TXIF level options have been built into the transverter. The IF levels
are adjustable on both transmit and receive and have a dynamic range of approx. 25dB. This is
useful for adjusting your maximum output power and setting the "S" meter level on your IF
receiver. The IF connections are via BNC connectors. Options have been provided for a key line
input PTT-H (+1 to 15 VDC) or PTT-L (a closure to ground) and auxiliary contacts on either
transmit or receive with a common line for many applications. The control, power, and auxiliary
connections are via DC feed thru connectors and the 3cm connectors are SMA. The 10368-144 is
housed in our standard 4.125" x 1.875" x 9.75" extruded aluminum enclosure that matches the all
of our other microwave transverters.
Connect your transceiver to the transverter:
Interfacing the transverter to the transceiver is easy. First review the assembled
configuration above. If the transverter was configured for direct connection to your transceiver (10
watts or less), follow the steps listed next.
1. Open the top lid of the transverter by removing 4 screws. Be careful because the LO is mounted
to the lid.
2. Connect all IF cables. The transverter may have a common IF port or two separate ports TXIF
and RXIF. Use good quality coax cable to connect the ports between your transceiver and the
IF connectors on the transverter.
/Built/10638-144_A32.doc 1 Rev B 12/28/2009
3. Connect the Push toTalk line out of your transceiver to the transverter. It is labeled PTT-H or
PTT-L on the transverter and uses a solder type DC feed through connector. The correct keying
type can be configured for your transceiver at time of order or you may select it in the
transverter now by moving the PTT jumper.
4. If the WTR option was not ordered, you will have separate TX and RX ports. You may connect
your own transfer relay at this time or continue interfacing without it. Connect your 3cm antenna
system or a dummy load with a power meter to the appropriate transverter ports. Always
terminate the receive port with a 50 ohm load.
5. Connect the external 10 MHz clock if you did not order the internal clock ,
6. Connect the DC power to the transverter. It uses a DC feed through type connector. 13.8 volts
is optimum but the transverter will operate normally from 11 to 15 volts.
7. Preset the TXIF and RXIF gain controls in the transverter. Turn both controls fully counterclockwise. This is maximum attenuation on Transmit and minimum attenuation on Receive.
8. Power your transceiver “ON” and leave it in the Receive mode on 144.100 MHz or the
respective IF frequency you have. This should be 10368.100 unless you ordered a different
frequency scheme. The Green LED and the Blue “Lock” LED should be lit. You can test the
external 10 MHz clock by disconnecting the clock. This should either produce a blinking blue
LED or totally off.
9. Adjust the RXIF gain control until a slight noise increase is heard in the transceiver or just a
slight movement in the “S” meter is detected. Power the transverter on and off to verify the
change of noise in the transceiver. You may also remove the 50 ohm load to determine receiver
performance. Find a signal on the band or use a signal generator to determine correct
frequency, or minimum signal level desired. If you are planning on installing an external LNA
you may adjust the IF level after installation.
10. It is recommended to test the transverter in the CW mode because most transceivers have
carrier level controls in this mode only. Do not use full or semi break-in if possible. Do not use
FM , SSB or AM because it may not be possible to obtain maximum output power with your
transceiver in these modes. Set the carrier/output power control on your transceiver to
minimum or “0” output power. Place the transceiver into transmit. If the PTT circuit is
connected correctly, the transmit LED on the transverter will switch on. While observing a
power meter on the 5cm system, slowly increase the carrier control (with key down) or increase
the power output control to maximum on the transceiver. If the transverter is configured
correctly for your transceiver, minimal power may be detected on the power meter. Slowly adjust
the TXIF control in the transverter in a clockwise direction while observing the power meter. Set
it to obtain a saturated power reading and then just back off a little to avoid total saturation. If a
power meter is not available this will be difficult. You may use a current meter on the DC power
line to determine if the transverter is transmitting. A maximum of 2.5 amps should be obtainable
and it should not vary as the TXIF control is adjusted. When maximum power is achieved the
current will suddenly decrease. This is saturation. Back off the TXIF drive to limit the amount of
saturation. Switch the transceiver to USB and make a transmission. The power output and
current drain should correlate to your speech pattern.
11. You may re-adjust both RXIF and TXIF again if desired. The local oscillator frequency should
not need to be adjusted but you may if you wish. Do not adjust any of the filters unless you
have access to a spectrum analyzer at minimum. It is also not recommended to adjust the bias
pots of the LNA and power amplifier. They have been optimized.
12. Put the top on the enclosure and install the screws. Your transverter system is ready to use.
Connect as you wish to use it in your 5cm system and have fun!
/Built/10638-144_A32.doc 2 Rev B 12/28/2009
Internal view of LP version enclosure layout.
Lock
A32
+9
RFOut
9VReg.
Switch
LED
LockLED
Load
TXRF
RXRF
+9
RX
TC
PCB
TX
10368TransverterPCB
M2M1
1136MHz.LO
+TX
TX
A32
RX
10MHz
IF
SMA
10MHz
External
orInternal
+LO
2MIF
10WMax.
RXIF
TC
TXIF
+RX
+9VDC
+13.8VDC
Wiring Block diagram
/Built/10638-144_A32.doc 3 Rev B 12/28/2009
PipeCaps
TX
IF
RX
PTT
GND
+
10MHz
Aluminum
Plate
PCB
13.8VDCAUX
End Plate connector assembly.
10368-144LP Transverter Board Parts List
All components are Surface Mount. All resistors are 1206 size unless indicated. All
capacitors are 1206 size except for 1.0ρF are ATC. All others are as indicted
The performance of the A32 synthesizer depends on the accuracy of the 10 MHz clock or
standard it is connected to. For the best possible performance, we recommend using a GPS
derived source. This not only guarantees the best possible performance but will ensure that you
are on the same frequency as others using a GPS derived system. The next best option is an
external 10 MHz. source that is temperature stable separate from the transverter it is being used
with. The transverter temperature will vary depending on the ambient temperature and the amount
of power dissipated as heat in the transverter. Hence, the low power transverters will be more
temperature stable than the high power versions. The last option is to utilize an “on board” 10 MHz
clock installed on the A32 synthesizer. This document will address the use and performance of
what DEMI will install if a internal 10 MHz clock is desired.
The latest production A32 units have been designed to accommodate a surface mount
TCXO produced by FOX, model 801BE. It was chosen for its performance over other designs. This
model does have temperature compensation but it will not out perform and external source. The
801BE does have an internal trimmer control but we found it difficult to adjust so have installed an
“on board” frequency trimmer. This trimmer is adjusted at room temperature (25-28 degrees C) for
the correct frequency depending on the model of transverter and operating frequency chosen. This
trimmer can be re-adjusted at anytime to compensate for your type of operation or oscillator aging.
The data provided below will demonstrate what to expect as the internal air temperature of
the transverter changes. The data is a compilation of worst-case frequency change of different
units tested in the lab at the specified temperature ranges. We believe this is a good
representation of what someone could expect when using an A32 with an internal FOX 801 10
MHz clock. Because of the nature of the 10 MHz clock (being crystal derived) the frequency
change over temperature depends on the characteristics of the crystal used in the circuit. This is
why we specify it as “Change in frequency or Delta” and not actual frequency change in a positive
or negative direction. The delta can be in either positive or negative direction from “0” offset or “0”
could be the center of the range. Just understand that at any temperature range, the data is the
maximum frequency change that was observed.
Next item to understand is that data is a measurement of the A32 frequency change. (The
base LO Multiplier frequency) This means that if you have a 10 GHz transverter, the base A32
frequency of 1136 MHz, is multiplied 9 times. So, the delta specified needs to be multiplied by 9.
For 5760 by 5, 3456 by 3 and 2304 by 2.
Last item is to not underestimate the operating temperature of the transverter. A high power
5 or 10 GHz. transverter if left unattended in the sun in the transmit mode can exceed an internal
temperature of 60 degrees C! In a laboratory environment, 50-55 degrees C can be achieved with
a ½ hour of continuous transmit time. Now, the data.
Operating Temperature Delta Frequency Change in Hz.
-10 to +50 degrees C 375
+20 to +40 degrees C 200
+30 to +55 degrees C 110
DEM TC
/Built/10638-144_A32.doc 5 Rev B 12/28/2009
DEM TRANSVERTER CONTROL
The DEM Transverter Control (DEM TC) is the circuit board that controls all transverter
functions in the DEMI 2.3 GHz. -10 GHz. transverters. It was designed with many options and
depending on the configuration you have ordered (see configuration page of main transverter
document), the options may or may not be enabled in your transverter. This document will cover
all of the features available for understanding and make it possible to change the configuration at
any time to suit your requirements.
Circuit Description: (All functions mentioned may or may not be enabled in your transverter)
The DEM TC circuit board is mounted in the front of the transverter. It includes the DC
power switch and both the “Power On” and the “Transmit On” LED’s. The TC contains a 1.5 amp,
9 Volt regulator that supplies the transverter with all of the regulated DC voltage it requires and
allows some head room for other external circuits. The TC controls all of the IF switching functions
utilizing a high isolation RF relay that is rated through 1 GHz. It allows the use of any frequency of
IF up to 1300 MHz. On transmit it will allow the use of up to a maximum of 10 watts of drive
depending on configuration. The TC also incorporates adjustable attenuators for both transmit and
receive and has a provision for adding additional receive IF gain. The TC allows either a PTT High
or Low for keying the transmit and receive circuits. Another feature included on the TC circuit
board is a 24 Volt relay driver designed to operate most SMA relays used for Transmit and
Receive switching of the RF frequencies. This circuit may not work with certain types of relays but
will operate with any SMA relay supplied by DEMI. Other options include different auxiliary DC
switching schemes, keying the transverter through the IF coax, and supplying PTT keying signals
to external equipment. Connection and use of each circuit is explained below. Refer to schematic
and component list for all component designations.
RXIF Gain and Adjustment:
The installation of the receive IF gain stage is the most asked about device in the
transverter. If the transverter is to be installed at the antenna with a long run of coax for the IF line,
you may wish to install IC1. Understand that installing this gain stage will not improve the system
noise figure and in most cases it will slightly degrade it. If you wish to improve the system noise
figure, you should add a LNA at the RF frequency. Then depending on the gain of the additional
RF LNA, you may not need the RXIF gain stage even if the transverter mast mounted. If you wish
to install IC1, refer to the component placement to determine where it is installed along with its bias
resistor R9. Any low frequency MMIC may be used but select it for the correct amount of gain
required. Also, consider the noise figure unless you have a RF LNA in the system. Select the
value of R9 for the MMIC to be used for 13.8VDC operation. To bypass the gain stage, install a
leaded 120pF capacitor in place of IC1. Keep the leads short.
The RXIF gain can be adjusted with R7. There should be approximately 20 dB of range.
With your system completely connected, R7 may be adjusted to an acceptable level determined by
your ear. For best results, keep the gain to a minimum. Only a slight noise increase should be
noticed by cycling the power switch of the transverter. If your “S” meter of your IF radio is at half
scale, you have lost half of the dynamic range of your system. For the same reasoning, adding the
gain stage and then adjusting the RXIF to maximum will degrade the dynamic range further.
/Built/10638-144_A32.doc 6 Rev B 12/28/2009
TXIF Drive Level and Adjustment.
The TXIF drive level adjustment (R2) has approximately 20 dB of range. Depending on the
configuration ordered, this adjustment range might not be acceptable. If so the fixed attenuator
may need to be installed, removed, or adjusted. If you wish to use less than 50 milliwatts of IF drive
power, install a short jumper wire in the R4 position and remove the large 50 ohm termination that
may be installed on the front panel. If you wish to use up to 2 watts, install R4 as shown with the
large 50 ohm termination. If you plan to use 1 - 10 watts of IF drive, install a 1pF capacitor in the
R4 position with the 50 ohm termination. If you need to experiment with other drive levels, any
combination of variable capacitor or resistor may be used in the R4 position. You may also adjust
the values of R1 and R3 as needed. Input power to the TXIF adjustment is dependent on the
attenuation installed on the C3 side of the K1 relay. The 50 ohm load resistor is designed to
handle 35 watts with proper heat sinking. When mounted to the front panel of the transverter, it
will not tolerate more than 10-12 watts reliably for a long period of time. You may experiment with
external heat sinking if you desire. External attenuation may also be used in the transceive path.
Remember that the added attenuation is also on the receive signal but may be overcome by the
additional gain of the RXIF gain stage. The level then may be adjusted with the RXIF adjustment.
Split Transmit and Receive or Common IF Configuration:
If you wish to use your transverter with separate TX and RX ports, first remove C3 and C5.
Then attach coax from the IF connectors to the corresponding TXIF and RXIF connections at the
C3 and C5 locations. If you are converting a split IF to a common IF, C3 and C5 may or may not
be already installed. Select the coax you wish to keep as the common and connect it to the
common input of K1.
PTT-H and PTT-L
The TC has the option of either using a PTT-H or PTT-L keying circuit. The PTT-H requires
+1.5 to +18VDC to activate it and will sink up to 2 mA. If using this circuit, be certain that the sink
current will not exceed your transceivers rating. The PTT-L circuit requires a connection to ground
to be activated. It is connected to the K1 relay and will source up to 25 mA to ground when keyed.
If this exceeds your transceivers rating you may modify the TC as shown in our design note DN0??
Found in our library on our web site or call for a copy.
PTT Keying Through the IF Coax:
Some transceivers such as certain models of the Yeasu FT290 supply a positive voltage on
it’s RF output connector during transmit or receive. This voltage may be used for keying the
transverter. After verifying or modifying your transceiver for this function, the transverter may have
the option installed. Select a choke of 1.0 μh or larger and install it in the L1 position of the TC.
Then connect a short wire jumper from the DC side of L1 to the PTT-H connection. When the
transceiver is keyed, the voltage in the coax will key the PTT-H of the transverter. This is the most
fool proof connection of the PTT line that can be made with any transceiver and is highly
recommended by DEMI.
If the PTT-L connection is connected to the PTT connector, it will not affect the operation of
the system. Just do not key both lines at the same time! If you will never use it, it may be
disconnected and the external connector may be used for any other auxiliary connections.
/Built/10638-144_A32.doc 7 Rev B 12/28/2009
+DC Switching Functions:
Relay K2 controls all of the +DC switching functions in the transverter. One side of the relay
switches the raw +DC supply voltage to the transverter and the other side switches the regulated
+9 volts. There are extra connection holes on the PCB if you require any additional switched
voltage. Be sure not to exceed the 1.5 amp limit on the 9 volt regulated supply. The transverter’s
current drain is listed on its configuration page and allow for some overhead when the oscillator is
not warmed up.
The switched voltages may be used for external LNA’s, switching circuits for power
amplifiers or relays. You may need to add an extra hole for a connector if the AUX connector is
used. Be sure to fuse any external connections. The relay’s contacts (K2) are rated for 3 amps.
24 Volt Relay Driver:
The TC is designed with a 24 Volt relay driver. A brief explanation of the circuit is as
follows. When the TC is in the receive mode, a 330 μF capacitor is charged to the raw input
voltage of the transverter (12-14 VDC). When the PTT circuit is activated, K3 switches this
charged capacitor in series with the TXON voltage and outputs a brief spike of 24-28 VDC at the
+R connection on the TC board. Depending on the current drain of the connected circuit (or relay),
the charged capacitor bleeds off down to the raw input voltage of the transverter. The spike is
enough to energize most SMA relays and the raw transverter voltage is enough to keep the relay
energized. This circuit will not work with all relays but will operate with all relays supplied by DEMI
in the optional WTR kit. If you wish to use a relay with a higher current drain, the 330 μF capacitor
may be increased. Just be sure that the relay being used will stay energized with +12 VDC. This
circuit will not operate latching relays unless additional circuitry is installed.
PLEASE NOTE! Even though this connection will bleed down to the raw voltage of the
transverter, the circuit should never be used on any electronic circuit that will not tolerate a
+28VDC input! It will damage most +12VDC circuits. It will also not operate any circuit requiring
voltage greater than the transverter’s supply voltage other than a relay.
If a switched +VDC is required, move the wire from the +R connection (if installed) to either
the +VTX, +RX, +9, +13RX, +13TX, or +13.8SW. Refer to the schematic for their functions.
RF Sensing Transverter Keying
The TC is not designed to be a RF sensed switch. It has 3 relays and it may be connected
to external mechanical relays. If any RF sensing scheme is added to the circuit, it will cause
excessive relay chatter that will not only ware out the relays prematurely, but could cause other
failures to external preamplifiers and or power amplifiers if used in your system. RF sensing
circuits are not recommended with any circuit that contains mechanical relays at RF frequencies!!
/Built/10638-144_A32.doc 8 Rev B 12/28/2009
DEM TC Component List
X
X
J
C1 0.01 μF C10 2.2 μF elect.
C2 0.01 μF C11 2.2 μF elect. R1 220 Ω R10 5.1KΩ
C3 0.01 μF C13 330 μF elect.
C4 0.01 μF
C5 0.01 μF
C6 0.01 μF
C7 0.01 μF
C8 0.01 μF
D1 -D6 1N4000
IC 1 MAR6 n
K1 G6Y relay
K2 G5V relay
K3 G5V relay R7 1K pot
C9 100 μF elect. L1 1.0 μh o R8 220 Ω
n To by-pass IF gain stage, install 120pF in place of IC1.
o L1 is used with transceivers that have + DC voltage on RF line during transmit
p Depending on the drive level used, R4 may be replaced with a short, a 1pF capacitor, or a
variable capacitor. See text for description.
Q1 PN2222
R2 1K pot
R9 330 Ω
R11 5.1KΩ
R3 220 Ω R12 330 Ω
R4 220 Ω p
R5 1K Ω
2 - Red LED
VR1 78S09
R6 220 Ω 50 Ω load
1 ρF p
TX
ADJUST
TX
X
D
7
D
8
R
AD
UST
XX
R
Caution:
Lift
Leads
LEDS
/Built/10638-144_A32.doc 9 Rev B 12/28/2009
TX
RX
8
D
7
D
/Built/10638-144_A32.doc 10 Rev B 12/28/2009
F5
U6
R12
F6
R13
U7
R14
F7
R15
U8
C28
R17
TX OUT
R16
10224MHz TP
D2
TX IF
R11
C19A/B
R9
RX IF
D1
VRX
R10
C20
R21
C34
U5
C21
F9
R20
C22
U10
C33
F4
R7R8
C23C24
VTX
R19
C32
C30
U4
F8
R18
C31
R6
U9
F3
C27
VTX
R5
U3
C26
C29
C25
RX IN
C16
C17
C18
C15
C14
C13
C12
C11
C10
+9
LO IN
C1
C2
U1
C3
3/4"
F1
R1R2
C4
C5
U2
C8
R4
C7
3/4"
F2
R3
C6
C9A/B
3408MHz TP
+9
10368-144LP TRANSVERTER SCHEMATIC
/Built/10638-144_A32.doc 11 Rev B 12/28/2009
10368-144
Rev D
TX RF
LNA + PA SECTION
+13 T X
C3 8
10W
3ohm
TO C 29
~ +10 TX
F11
C4 1
C4 0
Jumper
C4 3
C39
C3 5
5
6
1
4
2
C3 6
C3 7
R22
C5 0
C4 9
R23
Q1
R24
C4 6
Q2
R25
C4 5
R28
R26
C4 8
F10
R27
C5 1
C2 8
FROM
C5 2
+
C4 2
RX RF
C4 4
R31
D3
R29
R30
C4 7
/Built/10638-144_A32.doc 12 Rev B 12/28/2009
+9
LO
INPUT
VTX
VTX
+9
+9
VRX
TX IF
RX IF
4
4
1
8
6
3
0
1
Y
L
B
M
E
S
S
A
E
D
I
S
M
O
T
T
O
B
+13TX
+9
-5VDC
3
+10TX
+10TX
/Built/10638-144_A32.doc 13 Rev B 12/28/2009
W
0
1
m
h
o
VRX
-5VDC
-5VDC
4
3
C
C
R2
R1
C6
C5
C7
C8
R4
R3
1136
LO I N
10224
Test P oint
LP
C19 A
C2
C19
8
1
C
R10
U1
TX
R11
U2
1
2
1
1
C
R6
1
0
2
C
2
2
2
C
C
R13
U7
0
C
1
C
R5
U8
8
2
C
C30
C3 3
5
1
C
C32
4
3
1
1
C
C
R8
R7
U4
R12
U6
U10
C31
9
1
R
R18
U9
C29
6
7
1
1
C
C
R9
U5
D2
R20
C34
1
2
R
C1
RX
D1
C9
R16
R17
U3
R14
R15
C9A
C27
C2 3
C24
C25
C26
3408
Test P oint
LP
Layout
y
l
b
em
s
As
e
d
Si
Top
z
H
2
5
C
3
4
C
7
6
3
3
C
C
23
R
1
Q
C3 9
C4 2
C3 5
I C 1
L1
8
3
C
C41
C40
10368M
C47
R29
C46
Q2
5
R24
2
R
R26
8
5
2
4
R
C
C44
R27
C50
C49
C51
V R1
48
C
R31
D3
/Built/10638-144_A32.doc 14 Rev B 12/28/2009
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