8 KRC2
Elecraft KRC2 Band Decoder and Controller
Table of Contents
qq001 Introduction
qq002 Specifications
qq003 Assembly
qq004 Case Assembly
qq005 KRC2 Test Procedure
qq006 KRC2 Final Assembly
qq007 K2 to KRC2 Control Cable Assembly
qq008 Using the KRC2
qq009 Default Key Behavior
qq010 KRC2 Jumper Configuration
qq011 KRC2 Power Connections
qq012 Connecting the KRC2’s Drivers
qq013 Troubleshooting
:::
qq001 Introduction
The KRC2 is a universal, programmable station control unit that can switch
any combination of
antennas, filters, amplifiers, or other equipment. It supports analog,
digital, and RS232 control
inputs, so it's compatible with transceivers from Elecraft as well as other
manufacturers. Decoded
outputs are provided for all HF bands (including WARC bands and 60m), three
transverter bands,
and general accessories. High-side (source) and low-side (sink) relay
drivers are included. All
signal lines are RF bypassed to minimize RFI and noise pickup.
Individual driver outputs can be wire-ORed. However, the KRC2 also provides
a PC-based
command interface, allowing the user to configure the unit. New firmware can
even be
downloaded via the Internet.
Additional features are available when the KRC2 is used with our K2 and
K2/100 transceivers.
The ACC menu entry can be used to directly control the KRC2's accessory
outputs. Four buttons
on the top of the KRC2 can be used as "hot keys" for instant access to CW
message buffers, fast
switching of the RXANT jack, or other functions.
:::
qq002 Specifications
Outputs 32 (16 sink, 16 source)
Output Driver Ratings 500 mA max, 50 V max (sink and source)
Analog Inputs 0-5 V (1 input), 0-10 V (2 inputs)
Band Decode Formats Elecraft, Icom, Yaesu, Kenwood1
Internal Current Drain Approx. 20 mA (excludes output driver current)
Size 5.5" (L) x 3.5" (D) x 1.5" (H) (14 x 11.4 x 4 cm)
Caution: Some parts in this kit can be damaged by static discharge. Before
handling any
transistors or ICs, put on an anti-static wrist strap, or touch a grounded,
unpainted metal surface.
Firmware Requirements
To use the KRC2 with a K2 or K2/100 transceiver, you will need K2 main
microcontroller
firmware revision 2.01 or later and either the KIO2 or KPA100 options.
Note: The main K2 microcontroller is U6 on the K2 Control board. To check
your firmware
revision, hold any K2 pushbutton when powering up the K2. When you release
the pushbutton, the
revision will be shown on the LCD (left side).
:::
qq003 Assembly
- A fine-point, temperature-controlled soldering iron (700-800 degrees F
maximum) is
required to assemble the printed circuit board. A higher-wattage iron or one
with a wide tip
may damage components, pads, or traces. We also recommend the use of a
Panavise (or
equivalent bench vise) and an illuminated magnifying glass to facilitate PCB
and connector
assembly. Additionally, flush-cut wire cutters are recommended for steps
where component
leads must be cut close to the circuit board.
- To avoid soldering conflicts, install components only in the order
described below.
Double-check all values before soldering, since removing parts from
double-sided printed circuit
boards can be difficult.
- The leads on small capacitors can be fragile. When handling capacitors in
the
following steps, do not pull on the leads or bend them excessively.
- Locate the KRC2 PCB and identify the top and bottom sides. The side of the
board with
outlines of ICs U4-U7 and most other components is the top; the side with
the "KRC2" label is
the bottom. If an assembly step does not specify top or bottom, the
component should be installed
on the top side.
- Install the two 0.1-µF (104) capacitors with 0.1" (2.5 mm) lead spacing on
the top side of the
board
C25,C60
- Solder C25 and C60. Trim the leads of C25 as short as possible, using
flush-cutters if
available. If the leads are not kept very short, they will interfere with
installation of J5 on the
bottom side of the board.
- On the top side of the board, install the 0.01 µF (103) capacitors with
0.1" (2.5 mm) lead
spacing listed below, beginning with C28 in the upper center of the board
and proceeding in a line
to the end of the board. After installing each capacitor, bend the leads
outward to hold it in place.
The capacitors line up so that you can solder them in one step after
inserting them into the circuit
board. You may solder the components in smaller groups if desired.
- Note: When multiple items appear on one line in a component list such as
the one below,
complete all items on one line before moving on to the next, as indicated by
the small arrow. (In
other words, install C28 first, then C29, C30 and C31, then go to the second
line.)
C28,C29,C30,C31,C32,C33,C34,C35,C24,C23,C22,C21,C44,C45,C46,C47,C48,C49,C50,C51
- Solder the fixed capacitors. After soldering the leads of the capacitors,
be sure to flush trim
the leads so that terminals J6, J8, J10 and J12 will seat properly on the
bottom side of the PCB
when they are installed later in these instructions.
- On the top side of the board, install the small 0.01 µF (103) capacitors
with 0.1" (2.5 mm)
lead spacing listed below, beginning with C36 in the upper right of the
board and proceeding to
the end of the board. After installing each capacitor, bend the leads
outward to hold it in place.
C36,C37,C38,C39,C40,C41,C42,C43,C52, C53, C54, C55,C56, C57, C58, C59
- Solder the small fixed capacitors. After soldering the leads of the
capacitors, be sure to flush
trim the leads so that terminals J7, J9, J11 and J13 will seat properly on
the bottom side of the
PCB when they are installed later in these instructions.
- Install the three remaining small 0.01 µF (103) capacitors with 0.1”
(2.5mm) lead spacing
listed below on the top side of the PCB:
C7, C16, C17
- Solder the small fixed capacitors.
- Note: For all remaining assembly steps, you should solder then trim
component leads after
installing each group of components unless otherwise instructed. Leads can
be trimmed before or
after soldering, but trim them as short as possible.
- Install the two 33pF ceramic disk capacitors on the top side of the PCB.
Note that the lead
spacing for C1 and C2 may be too wide for the holes in the PC board. If so,
use a pair of needlenose
pliers to crush the ceramic ‘flash’ which covers the leads up close to the
body of the capacitor
and then re-bend the leads so they fit the available holes and scrape away
the crushed flash debris.
C1, C2
- Install the following 0.1µF (104) capacitors with 0.2” (5.0mm) lead
spacing on the top side
of the PCB:
C13, C14, C20, C26, C27
- Install the following 0.001µF (102) capacitors with 0.2” (5.0mm) lead
spacing on the top
side of the PCB:
C3, C4, C5, C6
- Install the following miniature inductors on the bottom side of the
circuit board. Then solder
and trim the leads. These miniature RF chokes are very fragile. Do not pull
on the leads, and keep
soldering time to a minimum.
L1 100µH Inductor, (brn-blk-brn)
L2 100µH Inductor, (brn-blk-brn)
L3 100µH Inductor, (brn-blk-brn)
- Install L4, a 15µH miniature inductor (brn-grn-blk) on the top side of the
PCB.
- Install C18, a 120pF (121) capacitor, with 0.1” (2.5mm) lead-spacing on
the top side of the
PCB.
- Install C19, a 56pF (560) capacitor, with 0.1” (2.5mm) lead-spacing on the
top side of the
PCB.
- Install the following 0.01µF (103) capacitors with 0.2” (5.0mm) lead
spacing on the top side
of the PCB:
C8, C9, C10, C11
- Install the following resistors on the top side of the circuit board.
R1 47k, (yel-vio-org)
R3 1k, (brn-blk-red)
R4 470 ohms, (yel-vio-brn)
R6 10K (brn-blk-org)
R7 10K, (brn-blk-org)
R8 10K, (brn-blk-org)
R9 100 ohms, (brn-blk-brn)
R10 10K, (brn-blk-org)
R12 4.7K, (yel-vio-red)
R13 47 ohms, (yel-vio-blk)
- Install two 1N4007 diodes D4 and D5 on the top side of the board. Make
sure the cathode
(banded end) of the diodes follow the same orientation as that silk-screened
on the PCB then
solder and trim the leads. D5 must be flush-trimmed on the bottom side in
order not to interfere
with J5. Be sure to save these cut leads for later use as ground jumpers.
D4, D5
- Install the following 1N4148 diodes on the top side of the board. Make
sure the cathode
(banded end) of each diode follows the same orientation as that
silk-screened on the PCB, then
solder and trim the leads.
D6, D7, D8, D9, D10
- Before handling ICs and transistors, touch an unpainted, grounded metal
surface.
- Install voltage regulator U3 (78L05C) on the top side of the board as
indicated by its outline.
The voltage regulator has a 3-pin TO-92 package, like a transistor. The
installed height of the
regulator must be no more than 3/8" (9 mm). Use a minimum of soldering time
(1-2 seconds per
lead).
- Locate the four pushbutton switches. One of these will now be installed on
the top side of the
board. Insert the switch into its mounting holes at S1, spreading the legs
slightly so they will
properly engage the holes. Press the switch down until it is fully seated on
the bends in its leads.
When the switch is fully seated, there will be a slight gap between the
switch body and PCB. This
is normal. Solder the switch onto the circuit board from the bottom side.
- Note: The pin 1 end of ICs can be identified by a notch or dimple as shown
in Figure 1. This end
must be oriented toward the notched end of the component outline.
- Install the following ICs on the top side of the board. Orient the notched
or dimpled end
toward the notched end of their PCB outline (pin 1 end, to the left).
Double-check the orientation
before soldering. Be sure to flush-trim the leads of each IC after soldering
so as not to interfere
with cables on the bottom side of the board.
U4 UCN5891A
U5 UCN5891A
U6 TPIC6595
U7 TPIC6595
- Install the rectangular Green LED at DS1 on the top side of the board.
Spacing the LED
about 1/8” (3 mm) above the board will nicely align the top of the LED with
the case top. The dot
marked on the PCB next to DS1 indicates the placement for the longest lead
of the LED.
Visual Inspection: Using a magnifying glass, examine the entire board for
unsoldered pins,
solder bridges, broken leads, or backward diodes or ICs. Reheat any suspect
joints This simple
check could save you hours of troubleshooting later.
- The following components will be installed on the bottom side of the
circuit board. Turn over
the circuit board to install the components.
- Install 1N4007 diodes at D2 and D3 on the bottom side of the PCB. Make
sure the cathode
(banded end) of the diode matches the silk-screened outline on the PCB.
D2, D3
- Install a 1N4148 diode at D1 on the bottom side of the PCB. Make sure the
cathode (banded
end) of the diode matches the silk-screened outline on the PCB.
- Install 10k, 1/4 watt resistors (brn-blk-org) at R2 and R11 on the bottom
side of the PCB.
R2, R11
- Install the 40-pin IC socket at U1 on the bottom side of the board. The
notched end should
be oriented toward the notched end of the PCB outline (pin 1 end, to the
left). Solder just two
corner pins. If the socket is not sitting completely flat against the PC
board, reheat these two pins
one at a time, pushing the socket down until it snaps into position. Then
solder the remaining pins
of the socket.
- Install U2, (MAX1406CPE or LT1039CN16) on the bottom side of the PCB.
Orient the
notched or dimpled end toward the notched end of their PCB outline (pin 1
end, to the left).
Double-check the orientation before soldering. There is no need to trim the
leads of U2.
- Install resistor network RP1, 390 ohms (391), 8 pins, on the bottom side
of the PCB. This
resistor network is symmetrical and can be installed in either orientation,
but for consistency you
should orient it with the pin 1 end (black dot) toward pin 1 of the PCB
outline (round pad, also
labeled "1").
- Install resistor network RP2, 47k (473), 8 pins, on the bottom side of the
PCB. This resistor
network should be oriented with the pin 1 end (black dot) toward pin 1 of
the PCB outline (round
pad, also labeled "1").
- Install low-profile crystal X2 on the bottom side of the PCB. This is a
short 16.289 MHz
device. Make sure it is flat against the board before soldering. Use a
minimum of solder so that it
does not wick through and cause a short on the opposite side of the PCB..
- Locate the ground pad near X2. Insert a discarded component lead through
this pad, then fold
it over the top of X2. Solder this lead at the ground pad, then solder it to
the crystal can. Avoid
overheating the crystal.
- Install electrolytic capacitor C15 (10 µF) on the bottom side of the PCB.
The (+) lead of C15
must be installed in the hole marked "+". The (+) lead is usually longer
than the (-) lead. The (-)
lead is identified by a stripe on the body of the capacitor.
- Install transistor Q1 (J310) as indicated by its outline on the bottom
side of the PCB. The
installed height of the transistors must be no more than 3/8" (9 mm). The
top of Q1 must be no
higher than the top of C15. Use a minimum of soldering time (1-2 seconds per
lead).
- Install the subminiature DPDT slide switch S5 on the bottom side of the
PCB. Make sure the
switch is firmly seated against the board when soldering. After installing
the switch, move its
handle to the position closest to J2.
- Install a 16-pin dual-row header at W1-W8 on the bottom side of the PCB.
The short pins
are inserted into the PCB. The header must be firmly seated against the
board when soldering.
- Install a 16-pin dual-row header at W12-W19 on the bottom side of the PCB.
The short pins
are inserted into the PCB. The header must be firmly seated against the
board when soldering.
- Locate the remaining 16-pin dual-row header.
Cut the header into three pieces so that you have one
8-pin dual row header, a six-pin header and a 2-pin
header. This is best done using diagonal cutters. Cut
the header on the side, then bend the portion to be
cut off away from the rest of the header. The two
pieces should snap apart somewhat cleanly. Discard
the 2-pin header.
- Install the 8-pin dual-row header at W20-W23 on the bottom side of the
PCB. The short pins
are inserted into the PCB. The header must be firmly seated against the
board when soldering.
- Install the 6-pin dual-row header at W9-W11 on the bottom side of the PCB.
The short pins
are inserted into the PCB. The header must be firmly seated against the
board when soldering.
- Locate the shorting headers. Install 14 shorting headers on the dual-row
headers W9-W19
and W21-W23 by plugging them onto the header pins. Do not install a jumper
at W20 at this time.
- Install electrolytic capacitor C12 (220 µF) on the bottom side of the PCB.
The (+) lead of
C10 must be installed in the hole marked "+". The (+) lead is usually longer
than the (-) lead. The
(-) lead is identified by a stripe on the body of the capacitor.
- Install the DC barrel jack (J3) on the bottom side of the PCB.
- Install J2, a male PC-mount DB9 connector on the bottom side of the PCB.
This position is
next to the side of the PCB. The connector will “snap” into the board as its
mounting tabs “grab”
the board. Be sure you have installed the MALE connector (with pins) before
soldering the
connector pins onto the board.
- Install J1, a female PC-mount DB9 connector on the bottom side of the PCB.
This position is
approximately in the center at the end of the PCB. The connector will “snap”
into the board as its
mounting tabs “grab” the board. Be sure you have installed the FEMALE
connector (with sockets)
before soldering the connector pins onto the board.
- Refer to Figure 3, and install screw
terminal connectors at J4 and J5 on the
bottom side of the PCB. The opening
between the connectors forms a “trough” for
control cables to external devices. The
terminals must be mounted so their side
openings face this trough. Make sure the feet
of the terminals are firmly seated against the
board, leaving a very slight gap between the
body of the terminal and the PCB.
J4, J5
- Connect two terminals together end-to
end by sliding the tab of one connector into
the slot of another. This forms a single 8-pin
connector. Form three other eight-pin
terminals following the same procedure, then
install the screw terminals at the locations
indicated in Figure 3 on the bottom side of
the PCB. Make sure the terminals are
mounted so their side openings face the
trough. Also make sure the feet of the
terminals are firmly seated against the board,
leaving a very slight gap between the body of
the terminal and the PCB.
J6/J8, J7/J9, J10/J12, J11/J13
- Install crystal X1, a tall, 4.000 MHz
device, on the bottom side of the PCB. Make sure it is flat against the
board before soldering. Use
a minimum of solder to avoid the solder wicking through to the other side,
causing a short.
- Locate the ground pad near X1. Insert a discarded component lead through
this pad, then fold
it over the top of X1. Solder this lead at the ground pad, then solder it to
the crystal can. Avoid
overheating the crystal.
- Adjacent to J1, on the bottom side of the board, you will find two pads
connected by a white
line. Using one of the 1N4007 diode leads previously saved, install a 1/4"
(6 mm) tall U-shaped
ground jumper between these two pads, on the bottom side of the board. This
jumper can be used
as a ground point for test instruments.
- Locate the remaining three pushbutton switches. These will now be
installed on the top side
of the board. Insert the switches into their mounting holes at S2, S3 and
S4, spreading the legs
slightly so they will properly engage the holes. Press the switch down until
it is fully seated on the
bends in its leads. There will be a slight gap between the switch body and
PCB. Solder the
switches onto the circuit board from the top side.
S2, S3, S4
- Locate the four pushbutton key caps. Making sure the key caps are oriented
from end-to-end
across the board, press the key caps onto the pushbutton switch stems until
they lock into place.
- Before handling U1, touch an unpainted, grounded metal surface.
- When you install the IC in the following step, always straighten the leads
of the IC first as
shown in Figure 4. The two rows of pins must be straight and parallel to
each other to establish the
proper pin spacing for insertion into the PC board or socket. To straighten
the pins, rest one entire
row of pins against a hard, flat surface. Press down gently on the other row
of pins and rock the IC
forward to bend the pins into position as shown below.
- Carefully straighten the pins on the microcontroller, U1 (PIC16F877A). The
two rows of pins
must be parallel to each other, with no pins bent.
- Press the microcontroller into its socket, orienting the notched or
dimpled end of the IC with
the notched end of its component outline. The labeling on the
microcontroller should read from
left to right.
- This completes assembly of the KRC2 circuit board. There are two remaining
parts locations, R5
and SP1, which are used with the accessibility speaker option. All other
component locations
should now be filled.
- Visual Inspection: Using a magnifying glass, examine the entire board for
unsoldered pins,
solder bridges, broken leads, or backward diodes or ICs. Reheat any suspect
joints This simple
check could save you hours of troubleshooting later.
:::
qq004 Case Assembly
- Locate the case top cover. This piece has three rectangular holes punched
into the face.
- Locate a 4-40 x 3/16” flat head screw. Push it through the hole on the top
of the case, holding
it in place with a finger as you turn the case over. Locate two #4
internal-tooth lock washers. Slide
both lock washers onto the screw shaft inside the case. Locate the 1/4 x
3/16” round threaded
standoff. While holding the screw with a Philips screwdriver, screw the
standoff onto the screw.
Tighten the assembly.
- Insert the circuit board assembly into the case with the pushbutton
switches and LED passing
through the rectangular holes in the case. Secure the circuit board to the
case with a single 4-40 x
3/16” pan head Philips screw and #4 lock washer.
- Locate the four #4 male-female hex standoffs. These are used to secure the
DB9 connectors
to the case. Screw each standoff through one of the mounting holes next to
the DB9 connectors in
the end of the case into the threaded DB9 assemblies.
- Locate the two “2-D” fasteners. These are used to secure the
case top and bottom. Note that on the side of the fastener with
two screw holes, there is more space to one side of the holes than
the other. The side with the most space will face away from the
circuit board.
- Using two 4-40 x 3/16” flat-head screws, attach one “2-D”
fastener to the case top just above the J1 DB9 connector. Make
sure the wide side of the fastener side faces away from the circuit
board.
- Attach the second “2-D” fastener, using two 4-40 x 3/16” flat head screws,
to the end of the
top case away from the DB9 connectors. Follow the same procedure as in the
previous step.
Again, the wide side of the fastener should face away from the circuit
board.
:::
qq005 KRC2 Test Procedure
The KRC2 should be powered from its DC barrel jack using a +12 volt supply
for its initial
power-up. No other connections should be made to the unit.
- Connect the power source to the unit. After a short delay while the KRC2
performs
diagnostics, the front-panel LED should turn on to its dim level. If this
does not happen, turn
power off to the unit and refer to the troubleshooting section.
Driver Relay Test: You will need a DC voltmeter for this procedure. Connect
the black lead
(common) to the ground jumper located near J1 on the KRC2. The red lead
should be used to
measure the voltage on each terminal of J6, J7, J8 and J9. Be sure to check
the voltage at the side
connector of each terminal. The initial readings should be 0 volts on each
terminal.
The Tap/Hold Rule: Each of the pushbutton switches on the front panel has
two functions, one
activated by a TAP (short press) and the other activated by a HOLD (long
press, about 1/2
second). To highlight this in the text, we use two different typographical
styles to identify
switches: TAP and HOLD.
- Holding F1 should cause the KRC2 to change the driven band terminal. Only
the 60m source
terminal should indicate 12 volts. The LED should be alternating between dim
and bright.
- Holding F1 again should cause the 10m source terminal to indicate 12
volts, and all others to
remain off.
- Continue this procedure, actuating the F1 command until all HF source
terminals have been
checked.
- The F4 function is used to switch the AC1-AC3 outputs. First, hold F4,
then tap F1. The
AC1 source terminal should now indicate +12V and AC2 and AC3 source
terminals indicate 0V.
- Hold F4, then tap F2. The AC2 source terminal should now indicate 12V with
AC1 and AC3
at 0 V.
- Hold F4, then tap F3. The AC3 source terminal should now indicate 12V with
AC1 and AC2
at 0 V.
- Hold F4, then tap F4. All three AC source terminals should now indicate 0
volts.
This completes checkout of the KRC2. Continue to the Final Assembly section.
:::
qq006 KRC2 Final Assembly
- Place the case bottom onto the case top, aligning the screw holes at each
end of the case. The
case may be a tight fit, but the two halves should slide into place without
difficulty.
- Using two 4 x 3/16” pan-head screws, secure the case bottom to the top.
- Locate the four rubber stick-on feet. Remove the adhesive backing from
each foot, and place
the foot securely into place in a corner of the case bottom about 1/8” in
from each side.
:::
qq007 K2 to KRC2 Control Cable Assembly
- Locate the 8-conductor cable. Note: A shorter cable may be used as long as
it accommodates
the physical orientation of the K2 and the KRC2. A longer cable can also be
used, but it will have
to be tested to ensure that it is not subject to RF interference. A more
heavily-shielded control
cable may be required. A standard shielded male-female DB9 straight-through
cable has been
tested and should work well with the KRC2/K2 combination.
- Remove 1/2" (12 mm) of the jacket from the cable at each end. Be very
careful not to nick
the individual wires.
- Peel back and cut away the foil shield.
- Strip 3/16" (5 mm) of insulation from each insulated wire.
- Twist the strands of each wire together. Tin lightly with solder.
- Locate the male and female DB9 connectors.
- Insert the female DB9 connector (KRC2 end) into the vise, with the solder
cups facing up.
- Solder the wires to the indicated connector pins at the KRC2 end of the
cable as shown in
Figure 6. It may be helpful to melt some solder into each solder cup on the
connector first.
Pin 1 Bare wire
Pin 2 Orange
Pin 3 Blue
Pin 4 Red with Black stripe
Pin 5 White with Black stripe
Pin 6 Green
Pin 7 White
Pin 8 Red
Pin 9 Black
- Remove the female connector from the vise (K2 or K2/100 end), and insert
the male
connector (KRC2 end). Solder the wires to this connector using the same
colors and pins as in the
previous step.
- Locate the connector housing (backshell) and associated hardware.
- Note: A single hinged backshell may be provided rather than a two-piece
backshell.
- Attach a backshell to the male connector at the
K2 or K2/100 end of the cable. Figure 7 shows how
the backshell appears when assembled. Use the
provided cable clamp to hold the cable in position,
then secure the clamp with two screws. The
jackscrews must be retained by the shells. Secure
the backshell halves with the provided hardware (or,
if the shell is hinged, snap the backshell closed). Do
not over-tighten the two screws which secure the
cable clamp!
- Attach the remaining backshell to the female
connector at the KRC2 end using the procedure
described above.
:::
qq008 Using the KRC2
KRC2 operation with an Elecraft K2 or K2/100 Transceiver
The KRC2 should be connected to the K2 using the Male/Female DB9 cable
assembly described
in the previous section. The KRC2 derives its operating power from the K2 in
this configuration.
In the KRC2's factory configuration, the per-band outputs (both sink and
source) will be turned on
or off based on the K2's selected band. This default behavior will suffice
for many amateur station
applications. However, the correspondence between selected band and output
driver states is fully
programmable. Band mapping and other configuration changes are accomplished
using the KRC2
configuration utility. (NOTE: At the time of this manual printing, the
configuration utility is still
in development. Refer to the KRC2 page on our web site for details.) For
example, if the station
includes a 20/15/10 meter tri-band beam, the 20 m sink output could be
programmed to be turned
on whenever the K2 is set for 20, 15, or 10 meters. Another alternative for
mapping multiple
bands to a single antenna or other device is to "wire-OR" the outputs. This
is explained in more
detail later in the manual.
Switch S5, accessible through a small hole in the side of the KRC2 sets the
operational mode of
the unit. For normal operation, the OP (operate) position of S5 is used.
This allows the KRC2 to
communicate with the K2 via its AuxBus and RS-232 interfaces. Set S5 to the
DL (Download)
position for downloading firmware upgrades or device configurations to the
unit. Firmware
upgrades can be downloaded using the KRC2 download utility. (NOTE: At the
time of this
manual printing, the configuration utility is still in development.)
:::
qq009 Default Key Behavior
There are four buttons on the top of the KRC2, labeled F1, F2, F3 and F4. In
the KRC2's factory
configuration, the F1-F4 buttons have the following TAP and HOLD functions:
F1 Sends the contents of K2 CW message buffer #1.
F2 Sends the contents of K2 CW message buffer #2.
F3 Sends the contents of K2 CW message buffer #3.
F4 Sends the contents of K2 CW message buffer #4.
Note: Playing messages using F1 - F4 is more convenient than using the K2’s
FAST PLAY (1-touch) technique.
F1 Selects the next lower HF band’s relay driver output in the KRC2.
F2 Selects the next higher HF band’s relay driver output in the KRC2.
Note: This is useful in cases where you switch to a K2 band for which no
antenna
relay has been connected in the KRC2. See next page for details.
F3 Switches the K2 receiver to (or from) the RCV ANT jack. This is a toggle
operation.
F4 Holding this button, then tapping any button, will then cause one of the
ACC drivers
to be turned on or off as shown in the list below. The KRC2 will illuminate
the green
LED at full brightness while it is awaiting the key tap.
F1 Turn on AC1 driver.
F2 Turn on AC2 driver.
F3 Turn on AC3 driver.
F4 Turn OFF all ACC drivers.
Note that holding F4 instead of tapping a key will cancel the function.
The F1 and F2 functions change the output terminal for the relay drivers up
or down in single
band increments. When the highest band is selected, the next hold of F2 will
cause the drivers to
go to the 160m setting. Conversely, when the lowest band is selected, the
next usage of the F1
function causes the drivers to go to the highest band. The band map follows
the values indicated in
Table 5, which places the 60m band above the 10m band. Thus the sequence
will be:
…12m<->10m<->60m<->160m<->80m<->40m… While the selected driver is different
from the
current band indicated by the transceiver, the green LED will flash between
dim and bright states.
The XVT drivers do not participate in the sequence, and when the transceiver
selects a transverter
these buttons will not change the driver selection.
The behavior of the KRC2’s keys can be modified using the KRC2 configuration
utility. (NOTE:
At the time of this manual printing, the configuration utility is still in
development.)
:::
qq010 KRC2 Jumper Configuration
There are 21 jumpers in the KRC2 allowing for a wide range of device
options. The W1-8 block,
located near the front of the case, controls device configuration for
different radio setups and
driver output logic. Table 1 and Table 2 show the different settings.
Table 1
Jumper: W1
Jumper Out (default): Use digital band decoding
Jumper In: Use analog band decoding
Jumper: W2
Jumper Out (default): Band decode option bit 1 - see Table 2
Jumper In: Band decode option bit 1 - see Table 2
Jumper: W3
Jumper Out (default): Band decode option bit 2 - see Table 2
Jumper In: Band decode option bit 2 - see Table 2
Jumper: W4
Jumper Out (default): ACn drivers use 1 of 3 decoding
Jumper In: ACn drivers use binary coding
Jumper: W5
Jumper Out (default): Xvtr drivers use 1 of 3 decoding
Jumper In: Xvtr drivers use binary decoding
Jumper: W6
Jumper Out (default): No auto-report mode
Jumper In: Place XCVR in auto-report mode
Jumper: W7
Jumper Out (default): Attempt communications failure recovery
Jumper In: Recovery not attempted
Jumper: W8
Jumper Out (default): Normal key operation
Jumper In: Disables keys F1-F4
Table 2
W1: Out
W2: Out
W3: Out
Band Decode Source: AuxBus Mode – K2 operation
W1: Out
W2: Out
W3: In
Band Decode Source: Serial Port Mode – K2 or Kenwood operation
W1: Out
W2: In
W3: Out
Band Decode Source: Digital Input through J4
W1: Out
W2: In
W3: In
Band Decode Source: Not used
W1: In
W2: Out
W3: Out
Band Decode Source: Analog input using ALC input (DB9 pin 4)
W1: In
W2: Out
W3: In
Band Decode Source: Analog input using VRDET input (DB9 pin 7)
W1: In
W2: In
W3: Out
Band Decode Source: Analog input using 8R input (DB9 Pin 9)
W1: In
W2: In
W3: In
Band Decode Source: Not Used
Using the information from these tables, the following settings are
suggested for each radio:
- Elecraft K2: W1 - W8 removed PC log program in use
- Elecraft K2 W6 installed, others removed Stand-alone (no PC) operation
- Kenwood W3 installed, others removed PC log program in use
- Kenwood W3,W6 installed, others removed Stand-alone (no PC) operation
- Computer Printer Port W2 installed, others removed
- Icom: W1 installed, others removed. Input uses J1/2 pin 4
- Icom: W1,W2 installed, others removed. Input uses J1/2 J2 pin 9
- Yaesu FT817 W1,W3 installed, others removed. Input uses J1/J3 pin 7
W8 may be installed to disable the operation of the KRC2 keys if control
features are not needed.
The choice of the Icom setting is determined by the input pin for the J1 or
J2 connectors. If you
connect the input to pin 4, use the first setting. Otherwise use the second
setting.
Other jumper settings besides those recommended may be used as desired.
Jumpers W9-W23 are used to connect or disconnect the DB-9 connectors from
the KRC2.
Normally these jumpers should be left installed. When used with a K2, the
minimum jumpers that
must be installed in this block are W16, 18, 19, 21 and 23. DO NOT install
jumper W20 when
using the KRC2 with the K2. Doing so will cause problems in the K2,
including disabling SSB
output. If the PC connector (J1) is used to pass K2 information through to a
peripheral such as a
KAT100, it is important that all jumpers in the W9-W23 block with the
exception of W20, be
installed.
W9 J1 Pin 2 - PC Enables Serial Data to PC from KRC2 or XCVR.
W10 J1 Pin 3 - PC Enables Serial Data from PC to KRC2 or through to XCVR.
W11 J1 Pin 4 - PC Enables J1 Pin 4
W12 J1 Pin 9 - PC Enables J1 Pin 9
W13 J1 Pin 8 - PC Enables J1 Pin 8
W14 J1 Pin 7 - PC Enables J1 Pin 7
W15 J1 Pin 6 - PC Enables J1 Pin 6
W16 J2 Pin 6 - XCVR Enables K2 AuxBus signal into KRC2. Must be installed
for
KRC2 AuxBus band decode mode operation.
W17 J2 Pin 7 - XCVR Enables K2 VRDET signal into KRC2.
W18 J2 Pin 8 - XCVR Enables K2 12CTRL signal into KRC2. This signal normally
powers the KRC2.
W19 J2 Pin 9 - XCVR Enables K2 8R signal into KRC2. Used to determine
transmit/receive activity in K2 operating mode.
W20 J2 Pin 4 - XCVR Enables K2 ALC signal into KRC2.
DO NOT insert this jumper when using the KRC2 with the K2!
W21 J2 Pin 3 - XCVR Enables K2 TxD signal from KRC2 serial port driver.
W22 J2 Pin 3 - XCVR Enables K2 TxD signal from J1 pin 3 (PC serial port
driver).
W23 J2 Pin 2 - XCVR Enables K2 RxD serial port signal into KRC2.
When the KRC2 is set to receive band data in an analog mode, the jumpers
associated with the
selected input should be removed from the J2 connection. The analog input
should then be fed into
the KRC2 using the PC connector. Use J1 pin 1 for the ground return
connection. These settings
and connections are listed in Table 4.
Table 4
Analog Input: 8R/AN1
Remove Jumper(s): W19
J1 Pin for input: 9
Comments: 0 - 10 volt input range
Analog Input: VRDET / AN2
Remove Jumper(s): W17
J1 Pin for input: 7
Comments: 0 - 5 volt input range
Analog Input: ALC / AN3
Remove Jumper(s): W20
J1 Pin for input: 4
Comments: 0 - 10 volt input range
Using the information from Table 3 and Table 4, the following settings are
suggested for each
radio:
• Elecraft K2, Use with PC:
W9, W10, W16-W19,W21-W23 installed, W11 – W15,W20 removed.
• Elecraft K2, Standalone or used with Elecraft peripheral:
W9-W19, W21-W23 installed, W20 removed.
- Kenwood W9, W10, W21-W23 installed, W11-20 removed.
- Icom: Icom 0-8V analog band input to J1 or J2 pin 4:
W11, W20 installed, W9, W10, W12-19, W21-W23 removed.
• Icom: Icom 0-8V analog band input to J1 or J2 pin 9:
W12,W19 installed, W9-W11, W13-W18, W20-W23 removed.
• Yaesu FT817 Yaesu 0-5V analog band input to J1 or J2 pin 7:
W14, W17 installed, W9-W13, W15, W16, W18-W23 removed.
For all analog inputs, use J1 or J2 (same connector as the analog input),
pin 1 for ground
connection.
This information is described in more detail in the sections below.
Important! Do NOT use the jumper connections to bridge external RS-232
serial port signals. This may cause serious damage to your radio when moving
the
KRC2 from one radio to another. The preferred method is to provide the
bridging
in the cable used with the radio needing it. This specifically applies to
Kenwood
transceivers.
:::
qq011 KRC2 Power Connections
The KRC2 may be powered from one of several sources. The
microcontroller and logic are powered either from the K2 through the
DB-9 connector, or from the +12V DC barrel jack. The voltage
applied at the DC barrel jack must not exceed 15 volts.
Power for the Source drivers can come either from the DC barrel jack
or the J5 terminal connector. Voltage applied to the J5 ‘V’ terminal
must not exceed +50 volts. Maximum current drain for either source is
1 amp.
:::
qq012 Connecting the KRC2’s Drivers
There are 36 driver output terminals. The terminals are accessible by
removing two access screws on the bottom case. Sixteen of the drivers
will source current, and another sixteen will sink current. The
remaining four drivers, labeled A, B, C and D, are TTL-compatible
inputs or outputs depending on the operating mode. In normal KRC2
or analog modes, the terminals are outputs. In digital parallel input
mode, they become inputs, and receive the BCD-encoded band data.
An additional four terminals are provided for connecting the KRC2 to
ground returns, and to provide a supply voltage for the source drivers
as described in the KRC2 Power Connections section. Figure 8
illustrates the connections. A bar over the terminal label indicates the
output is a sink driver. Sink driver terminals are located near the front
of the box. Source drivers are located toward the rear of the box.
Like-drivers may be wire-ORed (connected together) in order to allow a relay
to be selected on
more than one band. For example, the control line from a tri-band beam would
connect to
terminals 20, 15 and 10 for source drivers, or /20, /15 and /10 for sink
drivers.
IN NO CASE SHOULD THE SOURCE AND SINK TERMINALS BE CONNECTED
TOGETHER IN ANY WAY!
Connecting other Elecraft Peripherals
Additional Elecraft peripherals, such as a KAT-100 or XV-Series transverter,
may be connected to
the KRC2’s PC port in a “daisy-chain” fashion in order to operate with the
K2. Simply plug the
DB-9 connector from the peripheral into the KRC2’s PC port, and use the
peripheral as if it were
directly connected to the K2. Be sure to follow the rules outlined in the
jumper discussion and
insert all jumpers in the W9-W23 block with the exception of W20 when using
this configuration.
KRC2 PC Connections
A personal computer’s RS-232 serial port may be connected to the KRC2’s PC
port using the PC
connector. Normally the K2 does not automatically report its settings to the
KRC2. If you have an
alternate KRC2 configuration that needs for the K2 to report its settings,
install jumper W6 to
enable the K2’s auto-report mode.
Using the KRC2 with non-Elecraft Radios
The KRC2 is designed to accept band information from radios other than the
K2. As discussed in
KRC2 Jumper Configuration, setting jumpers W1-3 for Kenwood mode operations
allows the
KRC2 to interface with those radios in a manner similar to the K2. Other
radios that do not use
this command set may not be interfaced using this mode.
To use the KRC2 with an ICOM transceiver that has analog (stepped voltage)
band output, you
should set the W1-3 jumpers for Analog Mode using the desired input (8R/AN1
or ALC/AN3),
and connect the transceiver’s analog output to the appropriate input pin on
J1 or J2. Be sure to
remove W19 or W20 as appropriate. Power the KRC2 using an external 12-volt
supply connected
to the KRC2’s DC barrel jack. The KRC2 should now set its band outputs
according to the voltage
presented by the radio.
The three analog inputs have slightly different characteristics you should
consider when choosing
which to use. The 8R/AN1 and ALC/AN3 inputs have voltage divider networks on
their inputs
that divide the input by 2. Thus their input range is from 0 to 10 volts.
The VRDET/AN2 input has
no divider network, giving it a voltage range of 0 to 5 volts. Each input
voltage is filtered through
a band selection table that determines the selected band. There are three
tables, one for each input.
The factory-configured tables are set up for Icom radios with voltage range
of 0 to 8 volts for the
wide-range inputs, with the third table set for the Yaesu FT-817
transceiver’s analog output. These
tables are user-configurable using a Web-based software tool. Check the
Elecraft web site for the
availability of this tool.
To use the KRC2 with a Yaesu radio or computer parallel port outputs, set
jumpers W1-3 as
follows: W1 OUT, W2 IN, W3 OUT as described in Table 2. You may then connect
the radio or
computer outputs to the KRC2’s ABCD terminals, with the return ground
connected to one of the
terminals labeled ‘G’. Power the KRC2 from an external 12-volt supply
connected to the DC
barrel jack. The unit should now switch the driver outputs in accordance to
the digital inputs it
sees. Note that in addition to the standard BCD outputs, the KRC2 recognizes
additional band
codes according to Table 5.
Binary coding Hex Band Binary coding Hex BAND
0001 01 160m 1000 08 12m
0010 02 80m 1001 09 10m
0011 03 40m 1010 0A 60m
0100 04 30m 1011 0B unused
0101 05 20m 1100 0C XVT1
0110 06 17m 1101 0D XVT2
0111 07 15m 1110 0E XVT3
:::
qq013 Troubleshooting
If you have any difficulty with your KRC2:
Most problems in building the KRC2 are caused by poor or non-existent solder
joints. Closely
examine the PC board for poor solder joints and incorrect, broken or missing
components.
Problem: The KRC2’s LED does not turn on.
Make sure the KRC2 is powered, either from the K2 or from the DC barrel
jack. The KRC2 must
be powered from one of these two sources. The internal controller circuits
may not be powered
from J5’s ‘V’ terminal.
Problem: Source drivers inoperative.
The source drivers require that a DC supply of up to 15 volts be attached to
the KRC2’s DC barrel
jack, or a DC supply of up to 50 volts be connected to terminal ‘V’ of J5.
The source drivers are
not capable of supplying voltage from the K2’s power supply.
Problem: KRC2 does not communicate with K2.
Check jumpers W9-W23. All but W20 must be installed for the KRC2 to
communicate properly
with the K2. If these are properly installed, check the cable connecting the
KRC2 and K2. This
must be a straight-through Male DB9-Female DB9 cable as constructed in this
manual.
Problem: K2 has no transmitter output in voice modes.
Remove jumper W20 from the KRC2. The KRC2 adversely affects the K2’s ALC
system, causing
low voice power output of the transceiver. The K2 works quite well without
the external ALC line
installed, so simply leave jumper W20 out of the KRC2.
Problem: LED Flashing on and off.
On/off LED flashing indicates that the KRC2’s microcontroller has not passed
its startup tests, and
is waiting for a firmware download. This is not to be confused with the
slower bright/dim LED
flashing which indicates the driver band selection does not match the K2’s
band setting. Try
turning power off then on to the unit. If the condition persists, contact
Elecraft technical support
for an upgrade.
Included below are complete DC Voltage Tables for all ICs.
:::
qq014 Circuit Details
Refer to the schematic diagram, Figure 7 on page 29.
U1 is a PCI 16F877A microcontroller. This device controls the operation of
the KRC2. U1
operates at a clock frequency of 4 MHz, as determined by X1. It communicates
with relay drivers
U4-U7 using its built-in Serial Peripheral Interconnect (SPI) interface,
commanding them to turn
their outputs on or off. Which outputs should be on or off is determined
during execution of the
microcontroller’s internal program. It uses band input from the attached
radio or computer to
determine which driver output(s) should be enabled.
The MCU receives band information from the attached radio through one of six
input channels.
Three channels are analog, using the MCU’s built-in analog to digital
converters to measure band
voltages, while the other three are digital in nature. These consist of a
BCD parallel input and two
serial inputs. One serial input enables the MCU to participate on the K2’s
AuxBus channel, while
the other uses the MCU’s built-in UART serial port to communicate using the
Elecraft serial
protocol (similar to the Kenwood serial protocol). Selection of the active
input method is made by
setting the W1-W3 jumpers.
The UART serial port uses industry-standard RS-232 voltages. These are
switched in the KRC2
using U2, a MAX1406 (or similar) RS-232 interface. U2 requires a negative
power supply for its
operation. This is developed using the oscillator and rectifier circuitry of
Q1. Q1 and X2 and their
associated components form an oscillator running at 18.289 MHz. Output from
this oscillator is
fed to a voltage-doubling rectifier made up of D6, D7, and C15, then fed to
U2’s –12V input pin.
The circuit typically provides –7.5 volts, well within the range required by
the RS-232
specification.
For analog band operation, the input voltage is connected to the
microcontroller’s AN1, AN2 or
AN3 inputs through divider or isolation networks. The AN1 input comes from
pin 9 of J1 or J2,
depending on jumper selection. It is reduced by the divider network made up
of R6 and R10. The
values for these resistors provide a division by 2, giving the input a
maximum range of 0 to +10
volts. The AN3 input is identical to that of AN1, with RR8 and R11 making up
the divide-by-2
network. This input comes from J1 or J2 pin 4. AN2 comes from J1/J2 pin 7,
and is fed directly to
the MCU input without a voltage divider. Its input range is 0 to +5V.
The KRC2 can communicate with two devices using the RS-232 port, depending
on the setting of
S5. In S5’s normal operation position, the KRC2 listens directly to the
transceiver’s serial output,
and also can send directly to the radio attached to the XVCR port.
Additionally, the RS-232
signals from a computer attached to the PC port (J1) are ORed with the
KRC2’s serial port,
allowing it to send, and listen, to the transceiver as well. No protection
is provided to keep
transmissions from the KRC2 and PC from colliding on this channel, so care
must be taken to
prevent this in the PC and KRC2 operation. The S5’s Download (DL) position
enables the
microcontroller to communicate directly with a PC. This is used in
downloading configuration and
firmware upgrades to the KRC2.
Disclaimer: The information on this site is provided as
a public service to the blind and visually handicapped community. While we have
done our best to ensure the information provided is accurate, please realize
the use of any information on this site is solely at your discretion and we
take no responsibility for use or attempted use of this information. |
