HAMTRONICS R306 Installation and operating instructions

©
2009
Hamtronics, Inc.; Hilton NY; USA. All rights reserved. Hamtronics is a registered trademark. evised:
8/10/11
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Page
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GENERAL INFORMATION.
The R306 is our 6th generation uhf nbfm
receiver. It is intended for demanding applica-
tions which require exceptional sensitivit and
selectivit . It is especiall suited for repeaters,
audio and data links, and remote control.
The R306 uses triple-tuned circuits in the
front end and excellent cr stal and ceramic fil-
ters in the i-f with steep skirts for close chan-
nel spacing or repeater operation. The i-f
selectivit , for instance, is down over 100dB at
±12 kHz awa from the carrier, which is 40-50
dB better than most transceivers. Low noise
fet's and surface mount parts in the front end
provide good overload resistance and 0.2µV
sensitivit .
The R306 features a positive-acting, wide-
range squelch circuit and additional output
terminals for low-level squelched audio and
discriminator audio as well as COS.
The frequenc is programmed in at the
factor and is aligned to frequenc ; so ou
have no adjustments to do at installation.
Volume and Squelch controls are trim pots on
the board for compact design. For those ap-
plications requiring adjustments on the out-
side of a cabinet, ou ma easil replace these
pots with suitable panel mount controls.
The frequenc reference for the R306 Re-
ceiver is a temperature compensated cr stal
oscillator (tcxo). This provides a temperature
stabilit of ±2ppm over a temperature range
of -30°C to +60°C without requiring a cr stal
oven.
INSTALLATION.
Mounting.
Some form of support should be provided
under the pc board, generall mounting the
board with 4-40 screws and threaded stand-
offs to a chassis.
The receiver board relies on the mounting
hardware to provide the dc and speaker
ground connections to the ground plane on
the board; so metal standoffs and screws
should be used for mounting.
Electrical Connections.
Power and input audio or data signals
should be connected to the solder pads on the
pc board with #22 solid hookup wire, which
can be extended to a connector or
feedthrough capacitors used on the cabinet in
which it is installed. Be ver careful not to
route the wiring near rf components on the
board, for instance underneath the board.
Power Connections.
The receiver operates on +13.6 Vdc at
about 100 mA peak with full audio. Current
drain with no audio is onl about 38 mA. A
well regulated power suppl should be used.
Be sure that the power source does not
carr high voltage or reverse polarit tran-
sients on the line, since semiconductors in the
receiver can be damaged. The positive power
suppl lead should be connected to the re-
ceiver at terminal E3, and the negative power
lead should be connected to the ground plane
of the board through the mounting hardware.
Be sure to observe polarit !
Speaker.
An loudspeaker with an impedance of 8Ω
or greater should be connected to E2 with
ground return through the mounting hard-
ware. Use of lower impedance speaker or
shorting of speaker terminal can result in ic
damage. The receiver can also drive higher
impedances, such as the 1K to 20K input im-
pedances of repeater controller boards. There
is no need to load down the output to 8 ohms.
Antenna Connections.
The antenna connection should be made
to the pc board with an RCA plug of the low-
loss t pe made for rf. We sell good RCA plugs
with cable clamp. See A5 plug on website.
If ou want to extend the antenna con-
nection to a panel connector, we recommend
using a short length of RG-174/u coax with the
plug and keep the pigtails ver short.
We do not recommend tr ing to use direct
coax soldered to board or another t pe of
connector. The method designed into the
board results in lowest loss practical. When
soldering the cable, keep the stripped ends as
short as possible.
OPTIONS.
Repeater Use.
E5 provides a COS (carrier operated
switch) output which ma be connected to a
COR module to turn a transmitter on and off.
The output level is about 5V unsquelched and
0V squelched. There is a resistor in series with
the output to limit current. Therefore, the
voltage that appears at the COR board will de-
pend on the load resistance at the input of
that board. For best results, be sure that the
input resistance of the COR board is at least
47K. If the input resistance is too low, no
damage to the receiver will occur; but the
squelch circuit h steresis will be affected.
If our repeater controller uses discrimi-
nator audio, rather than the speaker output,
filtered discriminator audio is available at E4.
The level is about 2V p-p. Note that discrimi-
nator audio is not de-emphasized or
squelched. If ou need audio which is
squelched, take it from Repeater Audio termi-
nal E1. Level there is about 1V p-p.
Subaudible Tone Decoder.
To use our TD-5 Subaudible Tone Decoder
or a similar module, connect its audio input to
DISCRIMINATOR terminal E4. If ou want to
use it to mute the audio (instead of inhibiting
a repeater transmitter as is normall done),
connect the mute output of the TD-5 to E1 on
the receiver.
Multichannel Operation.
The R306 ma be programmed with more
than one channel. If ou ordered this option,
ou can change to the first alternate channel
b grounding E6 or the second alternate
channel b grounding E7. Grounding both
terminals selects the third alternate. Ground
terminals E8 and E9 are provided if ou want
to use jumpers, or ou can use an external
switch of some sort.
ADJUSTMENTS.
Frequency Netting.
All cr stals age a little over a long period
of time; so it is customar to tweak an re-
ceiver back onto the precise channel fre-
quenc once a ear during routine
maintenance. This adjustment is called “net-
ting”, which is a term going back to da s when
all stations on a network would initiall adjust
their VFOs to all be on the same exact fre-
quenc before operating as a net.
The adjustment should be done using an
accurate service monitor or frequenc
counter. Of course, make sure the test
equipment is exactl on frequenc first b
checking it against WWV or another frequenc
HAMTRONICS
®
R306 UHF FM RECEIVER:
INSTALLATION, OPERATION, & MAINTENANCE
Table 1. Quick Specification Reference
Frequency Range:
can be supplied from 400 - 470 MHz
Sensitivity (12dB SINAD): 0.2µV
Squelch Sensitivity: 0.15µV
Normal signal bw: ±5kHz deviation
Adjacent Channel Selectivity:
±12 kHz at -100dB! (narrower bandwidth
is available as an option)
Modulation Acceptance: ±7.5 kHz
Audio utput: up to 1 Watt (8 ohms).
perating Power: +13.6Vdc at 38-100 mA,
depending on audio level.
Size: 4 in. W x 2.5 in. D

©
2009
Hamtronics, Inc.; Hilton NY; USA. All rights reserved. Hamtronics is a registered trademark. evised:
8/10/11
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standard.
The channel frequenc is trimmed pre-
cisel on frequenc with a small variable ca-
pacitor, which is accessible through a hole in
the top of the TCXO shield can. The proper
tool is a plastic wand with a small ceramic or
metal bit in the end.
To perform this adjustment, it is first nec-
essar to verif that the discriminator is prop-
erl adjusted. Do this b connecting a dc
voltmeter to TP4. Connect a signal generator
set for 10.700 MHz to TP5 (left side of coil L9),
and set the level for a relativel strong signal
so there is ver little white noise. Adjust dis-
criminator coil T2 for 3.3Vdc. Then, reconnect
the signal generator to antenna connector J1,
and set it for the precise channel frequenc .
You can also use a strong signal on the air if
ou are sure it is right on frequenc . Adjust
the TCXO trimmer capacitor for 3.3Vdc (to
match the voltage obtained with the 10.700
MHz signal).
Setting Channel Frequency.
The channel frequenc is determined b
frequenc s nthesizer circuits, which use a mi-
crocontroller which is programmed at the fac-
tor . If ou need to change frequenc ,
contact the factor to get another micro pro-
grammed for the new frequenc settings.
ALIGNMENT.
A complete alignment is needed whenever
the frequenc is changed b more than about
1 MHz. Alignment ensures that the frequenc
s nthesizer is optimized at the center of the
vco range and that all stages are tuned to
resonance.
Equipment needed for alignment is a sen-
sitive dc voltmeter, a stable and accurate sig-
nal generator for the channel frequenc , and a
regulated 13.6Vdc power suppl with a 0-200
mA meter internall or externall connected in
the suppl line.
The slug tuned coil should be adjusted
with the proper .062" square tuning tool to
avoid cracking the powdered iron slugs. Vari-
able capacitors should be adjusted with a plas-
tic tool having a small metal bit. (See
website.)
MID MAX MIN
Capacitor Adjustment
☞
☞☞
☞Note: Meter indications used as refer-
ences are typical but may vary widely due to
many factors not related to performance, such
as type of meter and circuit tolerances.
a. Set the SQUELCH pot full counter-
clockwise and the VOLUME pot just a little
clockwise.
b. Connect speaker and +13.6 Vdc. You
should hear white noise.
c. Connect voltmeter to TP1 (insert
probe tip in pad on board). Adjust vco coil L1
for +2Vdc. (Although the vco will operate
over a wide range of tuning voltages from
about 1V to 5V, operation is optimum if the
vco is adjusted to 2V.)
d. Connect voltmeter to TP2 (insert
probe tip into pad). Adjust doubler variable
capacitor C21 for a peak. Note: the peak will
be small.
e. Adjust buffer variable capacitor C24
for a peak. This will be just a slight peaking
(increase) of the voltage.
f. Adjust C32 and C33 for a peak. Then,
re-peak C21, C24, C27, and C33 to ensure the
are all at maximum.
g. Connect stable signal generator to
TP-2. Set generator to exactl 10.7000 MHz.
Use a frequenc counter or s nthesized signal
generator so the frequenc is accurate. Set
level just high enough for full quieting. At 20
µV, ou should notice some quieting, but ou
need something near full quieting for the test
(about 200µV).
h. Connect dc voltmeter to Discrimina-
tor pad E4. Adjust discriminator transformer
T3 for +2.0Vdc.
 Be careful not to turn the slug tight
against either the top or bottom because the
winding of the transformer can be broken.
i. Connect signal generator to J1 using a
coax cable with RCA plug. Adjust signal gen-
erator to exact channel frequenc , and turn
output level up fairl high (about 1mV).
j. If necessar , adjust trimmer in TCXO to
net the cr stal to channel frequenc , indicated
b +2.0Vdc at Discriminator output terminal
pad. The frequenc normall will be ver
close; so ou ma not need to adjust it at all
except to compensate for aging.
Note: There are two methods of adjusting
the mixer and front end. One is to use a volt-
meter with test point TP-3. The voltage at this
point is proportional to the amount of noise
detected in the squelch circuit; so it gives an
indication of the quieting of the receiver. With
SQUELCH control full ccw, the dc voltage at
TP-3 varies from -0.5 Vdc with no signal (full
noise) to +0.9 Vdc with full quieting signal.
The other method is to use a regular profes-
sional SINAD meter and a tone modulated sig-
nal.
In either case, a weak to moderate signal
is required to observe an change in noise. If
the signal is too strong, there will be no
change in the reading as tuning progresses; so
keep the signal generator turned down as re-
ceiver sensitivit increases during tuning.
If ou use TP-3 with a voltmeter, the signal
can be modulated or unmodulated. If ou use
a SINAD meter, the standard method is a 1000
Hz tone with 3 kHz deviation.
k. Connect dc voltmeter to TP-3. Set
signal generator for relativel weak signal, one
which shows some change in the dc voltage
indication at TP3. Alternatel peak RF ampli-
fier and mixer variable capacitors C29, C30,
and C31 until no further improvement can be
made. When properl tuned, sensitivit
should be about 0.2µV for 12 dB SINAD.
 T1 and T2 adjust the cr stal filter for
minimum distortion. These are adjusted at
the factor and should not be disturbed. If
ou must adjust them, inject a signal exactl
on channel frequenc with a 1000Hz tone and
5kHz deviation. Adjust alternatel for mini-
mum distortion.
THEORY OF OPERATION.
The R306 is a frequenc s nthesized uhf
fm Receiver. Refer to the schematic diagram
for the following discussion.
Low noise dual-gate mos fet’s are used for
the RF amplifier and mixer stages. The output
of mixer Q6 passes through an 8-pole cr stal
filter to get exceptional adjacent channel se-
lectivit .
U4 provides IF amplification, a 2
nd
mixer to
convert to 455 kHz, a discriminator, noise am-
plifier, and squelch. Ceramic filter FL5 pro-
vides additional selectivit at 455 kHz. The
noise amplifier is an op amp active filter
peaked at 10 kHz. It detects noise at frequen-
cies normall far above the voice band. Its
output at pin 11 is rectified and combined
with a dc voltage from the SQUELCH control
to turn a squelch transistor on and off inside
the ic, which grounds the audio path when
onl noise is present. Inverter Q7 provides a
dc output for use as a COS signal to repeater
controllers.
The injection for the first mixer is gener-
ated b voltage controlled oscillator (vco) Q2.
The injection frequenc is 10.700 MHz below
the receive channel frequenc , and the vco
operates at one half the injection frequenc .
The output of the vco is doubled b Q3 and
buffered b Q4 to minimize effects of loading
and voltage variations of following stages
from modulating the carrier frequenc . The
buffer output is applied through a triple tuned
circuit (L4, L5, and L6) to gate 2 of mixer Q6.
The frequenc of the vco stage is con-
trolled b phase locked loop s nthesizer U2. A
sample of the vco output is applied through
the buffer stage and C2 to a prescaler in U2.
The prescaler and other dividers in the s nthe-
sizer divide the sample down to 5kHz.
A reference frequenc of 10.240 MHz is
generated b a temperature compensated
cr stal oscillator (tcxo). The reference is di-
vided down to 5 kHz.
The two 5kHz signals are compared to de-
termine what error exists between them. The
result is a slowl var ing dc tuning voltage
used to phase lock the vco precisel onto the
desired channel frequenc .
The tuning voltage is applied to varactor
diode D1, which varies its capacitance to tune
the tank circuit formed b L1/C16/C17. C13

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2009
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8/10/11
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limits the tuning range of D1. The tuning volt-
age is applied to D1 through a third-order low-
pass loop filter, which removes the 5kHz ref-
erence frequenc from the tuning voltage to
avoid whine.
Serial data to indicate the desired channel
frequenc and other operational characteris-
tics of the s nthesizer are applied to s nthe-
sizer U2 b microcontroller U1. Ever thing the
s nthesizer needs to know about the band, di-
vision schemes, reference frequenc , and os-
cillator options is generated b the controller.
+13.6Vdc power for the Receiver is ap-
plied at E1. Audio output amplifier U5 is pow-
ered directl b the +13.6Vdc. All the other
stages are powered through +5V regulator U6
for stabilit and to eliminate noise. Additional
filtering for the vco and buffer stages is pro-
vided b capacitance amplifier Q1, which uses
the characteristics of an emitter follower to
provide a ver stiff suppl , eliminating an
possible noise on the power suppl line.
TROUBLESHOOTING.
General.
The usual troubleshooting techniques of
checking dc voltages and signal tracing with an
RF voltmeter probe and oscilloscope will work
well in troubleshooting the R306. DC voltage
charts and a list of t pical audio levels are
given to act as a guide to troubleshooting. Al-
though voltages ma var widel from set to
set and under various operating and measure-
ment conditions, the indications ma be help-
ful when used in a logical troubleshooting
procedure.
Current Drain.
Power line current drain normall is about
38 mA with volume turned down or squelched
and up to 100 mA with full audio output.
If the current drain is approximatel 100
mA with no audio output, check to see if volt-
age regulator U6 is hot. If so, and the voltage
on the 5V line is low, there is a short circuit on
the +5Vdc line somewhere and U6 is limiting
the short circuit current to 100mA to protect
the receiver from damage. If ou clear the
short circuit, the voltage should rise again. U6
should not be damaged b short circuits on its
output line; however, it ma be damaged b
reverse voltage or high transient voltages.
Audio Output Stage.
Note that audio output ic U5 is designed
to be heatsunk to the pc board through the
man ground pins on the ic.
If audio is present at the volume control
but not at the speaker, the audio ic ma have
been damaged b reverse polarit or a tran-
sient on the B+ line. This is fairl common
with lightning damage.
If no audio is present on the volume con-
trol, the squelch circuit ma not be operating
properl . Check the dc voltages, and look for
noise in the 10 kHz region, which should be
present at U4-pin 11 with no input signal. (Be-
tween pins 10 and 11 of U4 is an op-amp ac-
tive filter tuned to 10 kHz.)
RF Signal Tracing.
If the receiver is completel dead, tr a
10.700 MHz signal applied to TP-2. Set level
just high enough for full quieting. At 20µV,
ou should notice some quieting, but ou
need something near full quieting for the test,
which requires about 200µV.
You can also connect the 10.700 MHz clip
lead through a .01µf blocking capacitor to
various sections of the cr stal filter to see if
there is a large loss of signal across one of the
filter sections. Also, check the 10.245 MHz
oscillator with a scope or b listening with an
hf receiver or service monitor.
A signal generator on the channel fre-
quenc can be injected at various points in the
front end. If the mixer is more sensitive than
the RF amplifier, the RF stage is suspect. Check
the dc voltages, looking for a damaged fet,
which can occur due to transients or reverse
polarit on the dc power line. Also, it is possi-
ble to have the input gate (gate 1) of the RF
amplifier fet damaged b high static charges
or high levels of RF on the antenna line, with
no apparent change in dc voltages, since the
input gate is normall at dc ground.
Synthesizer Circuits.
Following is a checklist of things to look
for if the s nthesizer is suspected of not per-
forming properl .
a. Check the output frequenc of the
vco buffer with a frequenc counter or spec-
trum anal zer.
b. Check tuning voltage at TP1. It
should be about +2Vdc. Actual range over
which the unit will operate is about +1Vdc to
just under +5Vdc. However, for optimum re-
sults, the vco should be tuned to allow opera-
tion at about +2Vdc center voltage.
c. Check the operating voltage and bias
on the vco, doubler, and buffer.
d. Check the 10.240 MHz TCXO signal at
pin 1 of the s nthesizer ic (actuall best to
check at pad next to pin 1; avoid tr ing to
probe surface mount ic leads which are close
together). A scope should show strong signal
(several volts p-p) at 10.240 MHz.
e. The data, clock, and latch enable lines
between the microcontroller and s nthesizer
ic’s should show ver brief and ver fast activ-
it , sending data to the s nthesizer ic shortl
after the power is first applied or a dip switch
setting is changed. Because this happens ver
fast, it can be difficult to see on a scope. Use
1mSec/div, 5Vdc/div, and normal trigger on
rising pulse.
Microphonics, Hum, and Noise.
The vco and loop filter are ver sensitive
to hum and noise pickup from magnetic and
electrical sources. Some designs use a
shielded compartment for vco’s. We assume
the whole board will be installed in a shielded
enclosure; so we elected to keep the size
small b not using a separate shield on the
vco. However, this means that ou must use
care to keep wiring awa from the vco circuit.
Having the board in a metal enclosure will
shield these sensitive circuits from florescent
lights and other strong sources of noise.
Because the frequenc of a s nthesizer
basicall results from a free running L-C oscil-
lator, the tank circuit, especiall L1, is ver
sensitive to microphonics from mechanical
noise coupled to the coil. You should mini-
mize an sources of vibration which might be
coupled to the Receiver, such as motors.
Excessive noise on the dc power suppl
which operates the Receiver can cause noise
to modulate the s nthesizer output. Various
regulators and filters in the Receiver are de-
signed to minimize sensitivit to wiring noise.
However, in extreme cases, such as in mobile
installations with alternator whine, ou ma
need to add extra filtering in the power line to
prevent the noise from reaching the Receiver.
Typical Dc Voltages and Signal
Levels.
Tables which follow give dc levels mea-
sured with a sensitive dc voltmeter on a sam-
ple unit with 13.6 Vdc B+ applied. All voltages
ma var considerabl without necessaril in-
dicating trouble. Signal levels at significant
points are also given. The charts should be
used with a logical troubleshooting plan. All
voltages are positive with respect to ground
except as indicated.
Use caution when measuring voltages on
the surface mount ic. The pins are close to-
gether, and it is eas to short pins together
and damage the ic. We recommend tr ing to
connect meter to a nearb component con-
nected to the pin under question.
Table 2. Typical Audio Voltages
Audio Test Point Normal Level*
U4-9 (Discriminator) 1.5V p-p audio
E4 (Disc Output) 1V p-p audio
E1 (Repeater Output) 600mV p-p audio
U4-11 1.5V p-p noise
(noise ampl output)
CW lug Vol Cont R32 300mV p-p audio
U5-3 (af ampl input) 0 to 100mV p-p
(depends on
volume control)
U5-5 or E2 0 to 5V p-p audio
(speaker ampl output)
* Readings taken with strong input signal
with 1000Hz modulation at ±3kHz deviation.

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2009
Hamtronics, Inc.; Hilton NY; USA. All rights reserved. Hamtronics is a registered trademark. evised:
8/10/11
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Table 3. Typical Test Point Voltages
TP1 Tuning V. Normally set at +2Vdc
TP2 Inj. Level +0.25Vdc
TP3 Sig. Level Varies from -0.5Vdc to
+0.9Vdc depending on
noise quieting with signal.
TP4 Freq. Varies with frequency of
input signal. Voltage at
this point normally is ad-
justed for +2.0Vdc with a
signal exactly on fre-
quency. Can vary a little
without being a problem.
Table 4. Typical Xstr DC Voltages
Xstr Stage E(S) B(G1) C(D) G2
Q1 dc filter 4.0 4.7 4.8 -
Q2 vco 0.95 1.6 3.8 -
Q3 doubler 0 0.68 2.6 -
Q4 buffer 0 0.74 2.7 -
Q5 RF ampl 0 0 4.8 2.4
Q6 Mixer 0.25 0 5 1.0
Q7 sq. open 0 0 5 -
sq. closed 0 0.65 0.15 -
Table 5. Typical IC DC Voltages
U2-1 2.3 U2-7 5
U2-2 2.1 U2-8 1.7
U2-3 5 U2-9 0
U2-4 5 U2-10 0
U2-5 0 - 4.5 U2-11 0
U4-1: 5 U4-10: 0.8
U4-2: 4.5 U4-11: 2
U4-3: 4.8 U4-12: 0.5 (with
U4-4: 5 sq. just closed)
U4-5: 3.8 U4-13:
U4-6: 3.8 0V (sq. open),
U4-7: 3.8 5V (sq. closed)
U4-8: 5 U4-14: 0
U4-9: 2 (Varies U4-15: 0
w/ freq.) U4-16: 1.8
U5-1: 1.4 U5-6: 13.6
U5-3: 0 U5-7: 7
U5-5: 6 U5-8: 1.4
Table 6. Typical Synthesizer Levels
Data signals from microcontroller U1:
Latch enable (LE), clock, and data signals
are constant stream of 5V pulses which can
be observed with scope set for dc input with
1mSec/div horizontal scan.
U3 TCXO output is approx sine wave signal
of 2.5V p-p.
PARTS LIST FOR R306 UHF
FM RECEIVER.
 Caution: static sensitive part. Use ap-
propriate handling precautions to avoid dam-
age.
Ref Desig Value (marking)
C1 0.1µf
C2 2pf
C3 100pf
C4 0.1µf
C5 100µf electrol tic
C6 0.15µf m lar (red)
C7 .01µf
C8 .001µf
C9,C10 100µf electrol tic
C11 0.1µf
C12 390pf
C13 5pf
C14 390pf
C15 100µf electrol tic
C16 12pf
C17 47pf
C18 7pf
C19 220pf
C20 100pf
C21 4.5pf variable (white)
C22 2pf
C23 100pf
C24 ** 4.5pf variable (white)
C25 220pf
C26 5pf
C27,C28 100pf
C29 ** 4.5pf variable (white)
C30 4.5pf variable (white)
C31 ** 4.5pf variable (white)
C32 ** 4.5pf variable (white)
C33 4.5pf variable (white)
C34 .0047µf
C35-C37 .001µf
C38 7pf
C39 4pf
C40 7pf
C41 .001µf
C42 0.47µf electrol tic
C43 0.1µf
C44,C45 .001µf
C46,C47 .01µf
C48 0.1µf
C49 10µf electrol tic
C50 220µf electrol tic
C51 0.1µf
C52 68pf
C53 220pf
C54-C56 0.1µf
C57 100µf electrol tic
C58 1µf electrol tic
D1 BB132 varactor diode
D2,D3 MMBT3904 used as diode
FL1-FL4 10.7MHz cr stal filter
(matched set of 4)
FL5 455kHz ceramic filter
J1 RCA Jack
J2 6-pin header
L1 1½ turn slug-tuned (brn)
L2 0.22µH RF choke
(red-sil-red-red)
L3,L4 2¾ turn air wound coil
L5 3¾ turn air wound coil
L6 4¾ turn air wound coil
L7,L8 2¾ turn air wound coil
L9 4¾ turn air wound coil
L10 2¾ turn air wound coil
Q1 MMBT3904
Q2-Q4 MSC3130
Q5,Q6  BF998 dual gate mos fet
(note: source is wide lead)
Q7 MMBT3904
R1 27Ω
R2 15K
R3 150K
R4 10K
R5 1K
R6,R7 27Ω
R8,R9 10K
R10 180Ω
R11 27Ω
R12 10K
R13 3.9K
R14 470Ω
R15 47Ω
R16 470Ω
R17 10K
R18 3.9K
R19,R20 100K
R21 27Ω
R22 2.2K
R23 330K
R24 22K
R25 27Ω
R26 47Ω
R27 270Ω
R28 330K
R29 15K
R30 2 MEG
R31 47K
R32 100K pot
R33 68K
R34 100K
R35 510K
R36 4.7K
R37 680Ω
R38 1K
R39 22K
R40 100K
R41 100K pot
R42 47K
R43 10Ω
T1,T2 10.7MHz IF xfmr
(T1005)
T3 455kHz IF transformer
(T1003)
U1  MC9RS08KA1 µP
U2  LMX1501A
U3  10.240MHz TCXO
U4  MC3361BP (smt t pe)
U5 LM386N-1
U6 78L05 regulator (smt t pe)
XU1 8 pin ic socket
Y1 10.245 MHz cr stal
** Note: C24, C29, C31, and C32 each
have 1pf capacitor tack soldered across pads
on rear of board.

©
2009
Hamtronics, Inc.; Hilton NY; USA. All rights reserved. Hamtronics is a registered trademark. evised:
8/10/11
-
Page
5
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©
2009
Hamtronics, Inc.; Hilton NY; USA. All rights reserved. Hamtronics is a registered trademark. evised:
8/10/11
-
Page
6
-