4SQRP Hilltopper-20 Manual - User Manual

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The ‘Hilltopper-20’ Transceiver K1SWL rev. 15 October 2018

The ‘Hilltopper-20’

…a compact 20M CW transceiver.

Offered by the 4-State QRP Group

The ‘Hilltopper-20’ Transceiver K1SWL rev. 15 October 2018

Features:

Frequency coverage: 14.000 to 14.350 MHz
Tuning:  100 Hz /20 Hz steps
Transmitter power output:  5W nominal
Receive current draw:   approx.. 60 mA.
Size:  4.35” x 3.95” x 1.07”, weight 8 oz.
Fully-integrated packaging- no wires.

‘On-the-fly’ CW speed control.,
Iambic mode A/B (selectable), 8-35 wpm.
Adjustments:  BFO trim cap,  one-time
Frequency Calibration
Frequency readout:  Audio Morse
SMT Parts (2):  Pre-installed

Description:

Receiver

The receiver is adapted from K1SWL’s ‘SW+’ Series with minor modifications. The front-end circuitry

was revised to replace the now-vanished 10.7 MHz IF transformers. The output of 1

mixer U1 is transformed to a

220 ohm value by L3/C8. The following crystal filter has a -3dB bandwidth of approximately 400 Hz. L4 and C12
step the impedance back up into the 2

mixer U2. Trimmer capacitor C53 provides adjustment of the BFO

frequency during the alignment process. The two op-amp stages following provide approximately 60 dB of audio
gain. The final audio stage is configured as a bandpass filter centered on 800 Hz with a Q of 2. The receiver
output is suitable for headphone use. An 800 Hz sidetone is injected into this final stage.

Transmitter:

The transmitter strip closely resembles Steve Weber’s – KD1JV- fine work. The frequency source

for both transmitting and receiving is an Adafruit Si5351 board.  This board outputs a 3V p-p square wave. The
‘CLK1’ signal is enabled (turned on) during Transmit directly at the operating frequency. The ‘QSK’ signal further
‘gates’ the CLK1 signal to eliminate a ‘back-wave’ between code elements.  U7’s three remaining gates are
paralleled for higher current drive into the PA devices Q5-Q7.  The low-pass filter design is based on a drain
impedance of 10 ohms and was optimized using the ELSIE modelling application.    The addition of C52- in parallel
with L7 provides a notch to reduce the 2

-harmonic content to FCC-compliant levels.

Wave-shaping:   Q4 is a P-channel MOSFET rated for 2A continuous duty -with proper heatsinking- and is turned on
when Q3 is on, conducting current to ground.   Capacitor C45 serves to make the supply voltage rise and fall linear.
Rise time is 2 mS and fall time is 4 mS. Note: R17, R18 and R21 are ‘insurance’, ensuring that the PA stage and
supply bias are firmly OFF during initial power-up.

MPU Controller

The controller IC is a 28-pin DIP- the Atmel ATmega328P used in the Arduino UNO. It relies

on an external 16 MHz crystal (Y6) for its timing. The application firmware was written in the Arduino environment
(more on this later). An on-board rotary encoder outputting 24 pulses-per-revolution provides a tuning function.
The variable DC voltage provided by Speed pot R16 is read by an A/D converter and scaled for Morse code timing.
A pair of inputs are used for dot/dash paddles, and Straight-key mode is also available. The remainder of the I/O
provides various control signals and sidetone for a variety of operations.

Firmware

: The Hilltopper firmware was written in Arduino’s (mostly) C language and supported by its own

compiler.  After power-up initialization, the main program runs in a fairly high-speed loop, awaiting keyer and
pushbutton inputs.  Encoder phase A is handled by a brief interrupt routine. That routine flags the presence of a
new tuning input and reads phase B to determine its up/down tuning direction.  Outputs ‘A4’ and ‘A5’ provide a
clock and serial data to the Si5351 board.  During Receive operation, CLK0 is active, and its output equals the
operating frequency plus the IF. During Transmit, CLK1 is active directly at the operating frequency. The
changeover is a fairly slow process, requiring a number of data bytes be sent to the Si5351 at a fairly low bit rate.
To avoid having to keep switching back and forth between code elements, there’s a 50 mS ‘hang’ time on key-up.

The Hilltopper firmware is open-source

and can be downloaded from

https://4sqrp.groups.io/g/HilltopperKit

See the ‘file

s’

section

The ‘Hilltopper-20’ Transceiver K1SWL rev. 15 October 2018

Parts list:

Qty.

Reference designator

Description

Notes/ markings

C6, C15

10 pF C0G cap

C40, C41

22 pF C0G cap

C1,C3,C8,C12,C16

47 pF C0G cap

C53

12-60 pF trim cap

brown

C17,C52

68 pF C0G cap

C7,C9,C11

100 pF C0G cap

C2,C10

150 pF C0G cap

C49

220 pF C0G cap

C51

270 pF C0G cap

C21,C22,C24,C50

470 pF C0G cap

C26

820 pF C0G cap

C27

.0022 (2200 pF) C0G cap

C4,C5,C13,C14,C31,C37,C38,C39
C47, C54

.01 uF cap

C18

.033 uF cap

C19,C20,C23,C25,C28,C32,C33,
C34,C35,C36,C42,C44,C45,C46
C48

0.1 uF cap

C29,C30, C43

100 uF electrolytic cap

All resistors are ±5% tolerance ¼ watt.

R13, R23

4.7 ohm

Yellow-violet-gold-gold

R14, R15

470 ohm

Yellow-violet-brown-gold

R22

1.0K ohm

Brown-black-red-gold

R1, R16

5K potentiometer, PCB mount

R2, R3, R11, R17-R21

10K ohm

Brown-black-orange-gold

R8, R9

22K ohm

Red-red-orange-gold

R4, R5

150K ohm

Brown-green-yellow-gold

R10

510K ohm

Green-brown-yellow-gold

R6, R7, R12

1.0M ohm

Brown-black-green-gold

CAL

2-pin male header, .100”

CAL

2-pin female jumper

1N5818 diode

Black case

D2, D3, D4, D5

1N4148 diode

Glass case, small

D6, D7

BAT85 diode

1N4756 diode

Glass case, larger

BNC jack, right-angle mount

DC power jack

J3, J4

Key and audio jacks, 3.5mm 3-cond.

6-pin .100” male header

not supplied in kit

4-pin .100” male header

not supplied in kit

The ‘Hilltopper-20’ Transceiver K1SWL rev. 15 October 2018

L1, L2

3.3 µH RF choke

Orange-orange-gold-gold

L3, L4

18 µH RF choke

Brown-grey-gold-gold

FT37-43 toroid

See group 7 instructions

L6, L7

T37-6 toroid

See group 7 instructions

Q1, Q3, Q5, Q6, Q7

BS170 MOSFET

J113 JFET

NTD2955

Small heat sink tab

U1, U2

SA612AD 8-pin SOIC-8 IC

(pre-installed)

NE5532

8-pin DIP IC

LM78M05

Small heat sink tab

ATmega328P

28-pin DIP IC

LM78L05

74AC08

14-pin DIP IC

Miscellaneous:

Si5351 board

Supplied with 8-pin
header strip. See group 3.

SW1

pushbutton switch

1/16” plastic spacer

Used with pushbutton sw

SW2

rotary encoder w/ switch

X1-X5

5.185 MHz HC-49/US crystal

Matched set

16 MHz HC-49/US crystal

#24 magnet wire

18” (45 cm) length

#21 magnet wire

24" (60 cm) length

Knobs

¼” #6 spacer unthreaded

5/8”#6 spacer, threaded

#6-32 x

⅟

” machine screw, pan head

#6-32 x

⅝

” machine screw, pan head

8-pin DIP socket

14-pin DIP socket

28-pin DIP socket

Assembly- general notes:

A number of components are polarity-sensitive: all semiconductor devices and diodes….and the
three electrolytic capacitors.

Capacitors these days are tiny! In sunlight, I can read their printed values with +3.0 reading
glasses. Most of the time, though, I use a 10-power eye loupe (~$3-4 from DigiKey). Likewise,
the adjustment slot on trim cap C53 is tiny as well. An eyeglass repair kit ($2 at discount stores)
has just the right teensy screwdriver.

Assembly sequence

: You’ll find 7 grouped assembly sequences in these pages. You don’t have

to follow them.

Caution

There’s one component installation where the order matters. That’s

diode D7, which is *under* the Si5351 board. Install it before you add the Si5351 board. It’s also

The ‘Hilltopper-20’ Transceiver K1SWL rev. 15 October 2018

important to ensure that the on-board connectors are installed ‘square and plumb’ to the PC
board surface.

BEFORE YOU START

Before getting started with building the Hilltopper 20, take some time to organize and
familiarize yourself with the parts provided and check them against the Parts List. Building over
a cookie sheet is recommended to minimize parts being lost. To prevent static damage, it is
recommended that the ICs not be removed from their anti-static packaging until you are ready
to install them. If parts are missing in your kit, send an email to the Hiltopper kitter listed at
4SQRP.com. He will promptly provide replacements.

It is helpful to acquire the necessary tools and supplies before beginning. These include:

*Soldering iron – 20 to 30W, preferably thermostatically controlled.
*Fine 60/40 rosin core solder
*Diagonal cutters
*Needle-nose pliers
*Fine file or emery board
*Flat blade and Phillips screwdriver

Schematic and Component Placement diagrams are provided as part of documentation package.
It is highly recommended to print a copy for reference during construction. As you build, you can
check off each construction step as you complete them in order. When you think you are done,
you can check the list to verify that all of the parts have been installed.

Snap off the enclosure sides from the sides of the two main boards. The boards are scored with
a V-groove so that they break free readily. Once separated, lightly sand the rough edges of the
breaks until smooth.

Further details may be found in the grouped assembly sequences.

Let’s get started!

Online Support

Search for ‘Groups.io’ on your browser and register to use their free

service. Find ‘

4SQRP.groups.io

and register to join. Once approved, find the HilltopperKit

subgroup and register for it in turn. This is a group e-mail reflector and supports images and
other file types.

Please note that the J5 and J6 header strips are not provided in this kit

See the ‘Files’

section of the subgroup for more information.

The ‘Hilltopper-20’ Transceiver K1SWL rev. 15 October 2018

GROUP 1 ASSEMBLY:

•

Install all (qty.15) 0.1 µF capacitors. These are labeled ‘104’ on one side. Restrain each

capacitor by spreading the leads apart on the underside of the board until you can solder it.

typically install 3 or 4 components, then solder each and clip off the excess lead length.

Locations are highlighted below.

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The ‘Hilltopper-20’ Transceiver K1SWL rev. 15 October 2018

GROUP 2 ASSEMBLY:

•

Install all (qty. 9) .01 µF capacitors. These are labeled ‘103’ on one side. Restrain each

capacitor by spreading the leads apart on the underside of the board until you can solder it.

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Locations are highlighted below.

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The ‘Hilltopper-20’ Transceiver K1SWL rev. 15 October 2018

GROUP 3 ASSEMBLY:

•

Install all components highlighted below. Some parts are in the static sensitive bag, with the

remaining parts used in future steps. The A detailed assembly sequence follows the
illustration.

•

Install DC power connector J2. Use a ¼-inch wide elastic band to hold the connector in

place temporarily.

Solder only one lead at first.

Flip the board back over and check to ensure

that the connector is aligned squarely on the board. Reheat the connection if needed to align
the connector properly. Once the alignment is OK, solder the remaining leads on the connector.

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The ‘Hilltopper-20’ Transceiver K1SWL rev. 15 October 2018

• Install power diode D1 (1N5818) and bias diodes D6 and

D7 (BAT85)

. Be sure to match the

banded end of the diode to that shown on the illustration.

D7 must be installed before the

Si5351 board is installed.

• Install electrolytic cap C43 (100 µF). This part is polarity sensitive. Install so the white band on
the case faces the rear of the board.

This also corresponds to the shorter wire lead.

• Install U4 (78M05) This part is polarity sensitive. Install so that its heat-sink tab faces the rear
of the board as illustrated.

• Install capacitors C40 and C41 (marked ‘220’ or “22J”) and X6 (16.00 MHz).

I use a narrow

(0.1”) strip of paper under the crystal can to stand the crystal slightly above the board. Once at
least one of the leads is soldered, the paper is removed.

• Install resistor R18 (10K ohm, brown-black-orange-gold)

• Prepare the Si5351 board. Cut one pin off the 8-pin
header supplied with the Si5351 and mate the 7-pin
strip to the board.

Save the cut-off pin.

Make sure

the insulated portion of the header is on the
underside of the Si5351 board. Solder just one pin on
the header strip. Check your work to ensure the
header strip is firmly and squarely seated on the small
board. Once it’s OK, solder the remaining pins.

• Install resistors R14 and R15 (470 ohm, yellow-
violet-brown-gold).

• Install the Si5351 on the main circuit board. Place
the cut-off header pin) under the edge of the Si5351
board to ensure that the board is level. Tape down the
Si5351 board and the header pin using transparent
tape. Flip the board over and solder one pin of the 7-
pin strip to the main board. As before, check your work
and then solder the remaining pins. Remove and
discard the tape and single header-pin. (Cut off excess
lead length on the underside of the board.)

• Install the 28-pin IC socket at U5. The notch at one end of the socket faces the rear of the
board as shown. If you install it backwards- leave it! The socket itself is not polarity-sensitive.

• Install capacitor C24 - 470 pF (marked ‘471’)

• Install 28-pin IC U5 (ATmega328P). This device is
polarity-sensitive. The dot and or/ notch at one end of
the device must face the back of the board. You will
need to bend the IC pins gently inward to mate with the
socket. The best approach is push the IC down on a hard
surface to bend one 14-pin row at a time evenly. Once

The ‘Hilltopper-20’ Transceiver K1SWL rev. 15 October 2018

you’ve installed the IC, ensure that all leads are seated in the socket.

• Install the 2-pin male header at the location identified as ‘CAL’ . (Keep the mating 2-pin female
jumper aside until construction is complete.)

GROUP 4 ASSEMBLY:

•

Install all components highlighted below. A detailed assembly sequence follows the

illustration.

• Install J3 and J4.
• Install Install U6 (78L05). Observe proper orientation on the board.

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The ‘Hilltopper-20’ Transceiver K1SWL rev. 15 October 2018

• Install resistor R4 – 150K ohm (brown-green-yellow-gold)
• Install resistor R22 - 1K ohm (brown-black-red-gold)

• Install resistor R11 – 10K ohm (brown-black-orange-gold)
(continued)
• Install resistor R10 – 510K ohm (green-brown-yellow-gold)
• Install

the 8-pin DIP IC socket at U3. The notched end of the socket faces to the right.

• Install the NE5532P IC at U3. This part is polarity-sensitive. Ensure that the notch/dot on the IC faces
to the right.
• Install capacitor C27 (.0022 uF, ‘222’)
• Install capacitor C26 (820 pF, ‘821’)
• Install capacitor C54 (.01 µF, ‘103’)
• Install resistors R7 and R12 (1M ohm, brown-black-green-gold)
• Install resistors R13 and R23  (4.7 ohm  yellow-violet-gold-gold)
• Install resistor R8 (22K ohm, red-red-orange-gold)
• Install electrolytic caps C29 and C30. Observe installation polarity.  The longer wire lead corresponds
to the positive (+) side of the cap.

The ‘Hilltopper-20’ Transceiver K1SWL rev. 15 October 2018

GROUP 5 ASSEMBLY: •

Install components highlighted below. A detailed assembly

sequence follows.

• Install transistor Q1 (BS170).

The ‘flat’ on the side of the transistor faces right.

• Install resistor R6 - 1M ohm (Brown-black-green-gold))
•Install transistor Q2 (J113).

The ‘flat’ on the side of the transistor faces right.

• Install resistor R5- 150K ohm (Brown-green-yellow-gold)
• Install capacitors C21 and C22 -  470 pF (marked ‘471’)
• Install resistors R2 and R3- 10K ohm (Brown-black-orange-gold)
• Install resistor R9- 22K ohm (Red-red-orange-gold)
• Install capacitor C18 -  .033 uF (marked ‘333’)
• Install capacitor C16 -  47 pF (marked ‘470’ or ’47J’)
• Install capacitor C17 -  68 pF (marked ‘680’ or ’68J’)

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The ‘Hilltopper-20’ Transceiver K1SWL rev. 15 October 2018

• Install crystal X5 – 5.185 MHz This is one of a matched set of 5 crystals, and may be used
interchangeably within the group
• Install capacitor C15 - 10 pF (marked ‘100’ or ’10J’)
• Install trimmer capacitor C53 - 12-60 pF (brown).

The ‘flat’ side of the capacitor faces right.

GROUP 6

ASSEMBLY: •

Install all components highlighted below. A detailed assembly

sequence follows.

• Install capacitors C1, C3, C8 and C12 - 47 pF (marked ‘470’ or ‘47J’).
• Install capacitor C6 - 10 pF (marked ‘100’or ;10J’).

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The ‘Hilltopper-20’ Transceiver K1SWL rev. 15 October 2018

• Install RF chokes L1 and L2 – 3.3 Uh. These are slightly larger in diameter than the resistors. They’re
marked with

two orange bands

– and several more bands which may vary in color.

• Install capacitors C2 and C10 -  150 pF (marked ‘151’).
• Install capacitors C7, C9 and C11 -  100 pF (marked ‘101’).
• Install RF chokes  L3 and L4-  18 Uh

Brown-blue bands.

• Install crystals X1 through X4 – 5.185 MHz.  As in the group 3 assembly, a narrow (0.1”) strip of paper
temporarily stands the crystals slightly above the board.
• Install diodes D2 through D5 -  1N4148.  Be to match the banded end of each diode to the banded
marking on the circuit board component outline.

Note: D3 and D4 bands to the right, D2 and D5 bands

to the left.

The ‘Hilltopper-20’ Transceiver K1SWL rev. 15 October 2018

GROUP 7 ASSEMBLY: •

Install all components highlighted below. A detailed assembly

sequence follows.

• Install R17, R19, R20 and R21 - 10K ohm (brown-black-orange-gold).
• Install Q4 (NTD2955).

Ensure that the heat-

sink ‘flat’ faces to the right as shown

• Install the 14-pin IC socket at U7.

The notch on the socket faces to the right as shown.

• Adjust the lead spacing on U7 as needed.

See images in group 3

. Install U7, ensuring that

the dot/notch on the IC body faces to the right

• Install transistors Q3, Q5, Q6, and Q7, (all BS170s) observing the installation polarity as
shown above.
• Install Diode D8 (1N4756).
• Install capacitor C49 - 220 pF (marked ‘221’).
•Wind 8 turns of #21 (thicker) wire on toroid L5 (FT37-43 gray toroid). Trim excess lead length
to 3/8” (1 cm). Using a small knife, gently scrape the insulation from the protruding leads. (

The

insulation will not melt when you apply a soldering iron

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The ‘Hilltopper-20’ Transceiver K1SWL rev. 15 October 2018

• Install L5.

A properly-wound toroid looks like this.

Note the following:

• Each time the wire goes through the hole it counts as a
turn. Doublecheck your work.
• The winding is evenly-spaced around the core.
• The leads are stripped prior to installation.
• The windings are tight. I pull the wire taut after each turn comes up over the outer edge of the
core.

•

and please

… no scrambled turns!

• Using a 10” piece of the #24 (thinner) magnet wire, wind
12 turns on a T37-6 (yellow) toroid. Prepare the leads as
above and install at L6.

• Using a 12” piece of the #24 (thinner) magnet wire, wind
14 turns on the remaining  T37-6 (yellow) toroid.  Prepare
the leads as above and install at L7.

• Install capacitor C50 -  470 pF (marked ‘471’).
• Install capacitor C51 -  270 pF (marked ‘271’).
• Install capacitor C52 -    68 pF (marked ‘680’ or ’68J’).

• Install BNC bulkhead jack J1. Use sandpaper or file to roughen plating to ensure a good solder
joint.

(

This completes assembly of the main circuit board

(GOOD TOROID)

BAD TOROID!

(

bad bad toroid!

)

The ‘Hilltopper-20’ Transceiver K1SWL rev. 15 October 2018

Final assembly:

Install four 5/8” (1.5 cm) threaded spacers at the
corners of the top cover using the shorter

⅟

”

screws

as shown at right.

2) Add one each end and side-panels

. When they’re

properly aligned, the tabs and notches at the ends
of each panel will interlock cleanly.

The front/rear

panels have tabs. The side panels have notches.

When these are in place, hold the panels in tension
by placing an elastic band around them as shown.

3) Put top cover in place. This is to ensure proper

placement of the circuit board and to ensure side
pieces are square.

Flip the assembly over. Insert the circuit board upside down into the unit with board
resting against the spacers attached to the top

5) There are bare tinned areas on each side panel. These

            must line up with the corresponding bare areas on the
            main circuit board.  Solder all 6 pairs of contact points
            between the main board and the panels.

Make sure

the panels line up with the edges of the cover.

Caution

– side panels get hot quickly and can

cause painful burns.

Solder the upper and lower inside corners of the panels
(8 pl. total).

This adds considerably to the enclosure

strength.

7) Remove the elastic band and the top cover.

8) Remove the top cover and set it aside.

9) Install the controls

– pots R1, R16, switch SW1 and

rotary encoder SW2. Discard the nut and washer
that comes with the rotary encoder. Place the two
white 1/16

” spacers on pushbutton switch SW1’s leads and install SW1. Then tack one

lead on each to hold them in place. Fit the top cover to ensure the controls will align with
holes. Holding the top cover, turn unit over and complete soldering the controls.

10) Perform the Alignment and BFO Pitch Adjustment processes as described in the next

section.

11) Replace the top cover with spacers.

A word about soldering:

The tinned areas are thermally-
isolated from the rest of the board
material.  25 to 40W iron and a fine
point tip are sufficient. Do not use a
high-wattage iron!  A proper
connection shows a smooth
transition across the joint and not
‘two rounded bumps’

The ‘Hilltopper-20’ Transceiver K1SWL rev. 15 October 2018

12) With the unit upside down, rest it on something so controls are held above the work

surface, set a spacer over each hole, carefully lay the cover on, then push the remaining

⅝

”

screws through the holes and spacers. Use a screwdriver, first turning counter-

clockwise until you feel each one seat, and then turn clockwise to tighten.

13) Install knobs on the three controls, using a small slot screwdriver on the setscrews.

Space the knobs slightly above the panel to prevent ‘rubbing’. The tuning knob must be
just high enough to allow the detent switch on the rotary encoder to function.

(

This completes assembly of the kit

The ‘Hilltopper-20’ Transceiver K1SWL rev. 15 October 2018

ALIGNMENT

There are two steps in the alignment process. The frequency calibration is performed first.

1) Frequency Calibration
2) BFO pitch adjustment

-----------------------------------------------------------------------------------------------------------------

Frequency Calibration

The Si5351 DDS board uses a standard-quality SMD crystal as its reference clock. As such,
your operating frequency may be off by a kHz or so at 14 MHz.

PROCEDURE

Tune your ‘big rig’ to 14060.00 kHz

2) Install the 2-

pin female jumper at the location marked ‘CAL’ to the right of U5.

3) Connect a 50-ohm load to J1. A matched antenna is OK.
4) Apply 10-14V DC power to J2 via a 2.1/5.5mm male plug.

Upon power-up, the Hilltopper will put out full power (5W nominal) for 5 seconds. During that
time, rotate the TUNING control to match the tone in your ‘big rig’ to your sidetone pitch. At the
end of 5 seconds, the transmitter stops transmitting and a calibration factor is calculated and
stored

in U5’s EEPROM. That value is retrieved on subsequent power ups

It’s possible you won’t find 5 seconds to be enough time for the calibration. If that’s the case,
remove-and restore- DC power. The 5-second routine starts over, allowing you to zero in on the
correct frequency.

IMPORTANT

: Remove the jumper at the’CAL’ location when this calibration is completed.

Remove-and restore- DC power to return to normal operation.

-----------------------------------------------------------------------------------------------------------------

BFO Pitch adjustment:

The quick method:

Tune in a CW station and adjust trim cap C53 using a teensy screwdriver. You’re looking for
maximum signal strength at the same pitch as the sidetone (800 Hz). It’s a 2-handed operation,
since you also need to work the tuning knob.

‘The better method:

Power up the hilltopper (it starts up on 14060.0.) Set your big rig to 14060.0 and send a string of dots

(low power, please!). Adjust C53 so that the received pitch in the Hilltopper matches your sidetone pitch.

* * *

Alternate method

: Connect a frequency counter to the center pin (and ground) and apply

D-C power. Adjust the tuning control as above.

The ‘Hilltopper-20’ Transceiver K1SWL rev. 15 October 2018

Operation

Startup

: Upon applying DC power to the Hilltopper, you’ll hear ’6 o R o’. In the headphones. This

indicates an operating frequency of 14060.0 Khz. If you tune above 14100, the readout will be in the form
of ‘1xx.x.

Frequency Readout:

Push the

‘Function’ switch briefly to hear your current frequency.

The readout is at the same speed as

your keyer speed setting.

Tuning step size:

Briefly pressing the tuning knob toggles the step size between 100Hz and 20Hz. The power-up default is
the 100 Hz step size.

RIT:

Push and hold the tuning knob down for at least a half-second. A two-

tone sequence, ‘boo-beep’

indicates that RIT is on.

Repeat to turn RIT off-

it’s annunciated by ‘bee-boop’.

TUNE Mode

Push and hold the Function switch for at least one second. (release the switch) The sidetone and
transmitter output turn on to allow adjustment of antenna tuners, etc. It stays in TUNE mode until:

• 5 seconds has elapsed

either keyer paddle is tapped

Paddle Reverse and Iambic Mode A/B Selection (

current production

)

Applying DC power to the Hilltopper while pressing AND HOLDING the Function switch. Release the
switch

when you hear ‘R ?’. Tap either key paddle within 2 seconds to reverse the paddles. (

Do nothing

and there’s no swap

Next, you’ll hear ‘B ?’. Tap either key paddle within 2 seconds to choose Mode B.

Do nothing, and Mode A is selected.

(Most operators prefer Mode A. )

You’ll then hear an ‘A’ or ‘B’ to

confirm your selection. Your selections are stored in non-volatile memory and the Hilltopper proceeds to
normal operation.

Straight Key mode:

Upon power-

up, the Hilltopper firmware checks the state of the ‘ring’ (middle) connection on the keyer

jack. If a ‘mono’ (2-pin) plug is used, that middle connection is grounded, and the Hilltopper automatically
follows the straight key or external keyer input.

Straight key ‘timeout’

After 5 seconds key-down, the transmitter output shuts off. Depress the

Function switch briefly to restore normal operation. The TUNE function works in Straight key mode but
returns to normal operation without operator action. The timeout provision is meant to protect the PA
devices

from a ‘stuck key’ situation.

Alternate Startup Frequency:

Pressing the TUNING switch down while applying DC power to the Hilltopper yields a startup frequency of
14030.0 kHz.. This saves a lot of knob-twisting if you usually work the low end of 20M

The ‘Hilltopper-20’ Transceiver K1SWL rev. 15 October 2018

Receiver Schematic:

The ‘Hilltopper-20’ Transceiver K1SWL rev. 15 October 2018

Transmitter/Controller

Schematic:

The ‘Hilltopper-20’ Transceiver K1SWL rev. 15 October 2018

Component Placement – Master

Acknowledgements:

Thanks to Steve Weber- KD1JV whose SOTA POP design influenced the design of the
transmitter section. He also graciously provided open-

source firmware…… which I proceeded to

mangle for this project.

Thanks also to David Cripe- NMOS- who played an invaluable role with enclosure layout,
technical liason with 4SQRP, and provided advice with component selection.

Dave Benson, K1SWL 14Nov. 2017

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