Multi-Mode Transmitter for
Balloons
1
Multi-Mode Transmitter
MODES
• Hellscreiber
• RTTY
• DominoEX
• SSTV
• CW
• APRS (soon)
• Onboard GPS
• In/Out Temp
• Battery monitor
• 1 W on HF
• 0.3 W on VHF (FM or SSB)
Frequency Agile from 3.5 MHz to 148 MHz
2
MMT schematic
A
B
C
+1 2V
J3
1
1
2
1
2
E
+5 V
+3 .3
U6
D3
U7
Vin
C9
J4
D
Vout
Vin
GND
C10
1
Vout
GND
C11
C12 C13 C14 C15
D4
+3 .3
2
J7
R12
1
R9
C6
0.1
1
TP1TP2
RXA
4.7k
RXB
ANT 1 is PASSIVE (REMOVE if active)
18
17
16
15
14
13
12
11
10
C17
ANT1
In ve ntek GPS
C18
J6
1
2
3
4
U8
+3 .3
L5
C19
27p
1
2
3
4
5
6
7
8
9
to Garmin GPS
3
R14
JP2
0
33nH
3
Jump if TTL GPS
+3 .3
R10
TXB
33
R11
1
C7
0.1
A
2
R13
(REMOVE R14 for p ass ive)
4
1
2
3
B
TP3
JP3
1
2-A2
2
TXA
33
C8
27p
GPS232
2-A2
GPSINV
2-A2
GPSTTL
3
C16
27p
C
4
D
E
3
MMT schematic
A
B
C
ASDX015A24R
+3 .3
J1
5
6
7
8
2
1
2
3
U2
+3 .3
R7
R5
U1
6
5
4
16.386M VCXO
+3 .3
+3 .3
LM61
3
20
21
23
5
6
GPS
18
8
16
1
2
3
4
5
R3 R4
7
10
11
12
15
13
19
U5
CY22393
2
C4
16
15
12
13
R6
1
22
+1 2V
14
J2
R1 R2
4
3
11
1
2
3
2
U4
2
14
CY8C29466
27
26
25
24
GPS232
1-E3
GPSINV
1-E3
GPSTTL
1-E3
1
2
3
+3 .3
28
+3 .3
R8
1
U3
3
1
2
3
4
1
E
1JP1
+1 2V
+5 V
D
3
3
L1
L3
L4
J5
1
2
Q1
C1
C2
L2
4
A
B
C3
C5
2N3866A
C
4
D
E
4
Multi-Mode Transmitter
Inventek GPS
- Built-in helical
antenna
- Battery backup
-For hot starts <1s
- TTL or RS-232
outputs
MMT-XMT
-Multi Mode XMT
-Can be used with
any GPS (TTL or
RS-232)
- Serial output for
Zigbee or
Maxstream 9Xtend
5
MMT Hellscreiber transmission
• On/Off keyed mode
• 8.163 msec per pixel
6
DominoEX mode
• MFSK mode
• 18 tones
7
dl-Fldigi
•UKHAS mod called dl-FLdigi for uploading data to SpaceNear.us server
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Spacenear.us/tracker
website
Displays positions decoded by
dl-FLdigi onto a Google Map with
chart and telemetry display box
- Designed by members of the
UKHAS group
- Ground stations
receiving telemetry are
shown as towers
- Parachute comes out
during descent
9
Spacenear.us/tracker website
- Shows landing
prediction in realtime (light blue
target)
-- Can also upload
chase car position
directly to server
via a wireless
cellular link
Telemetry must be uploaded in the following format:
$$callsign, sequence, time(UTC), lat, lon, alt(m), sats, batt, temp*<cksum>
$$WB8ELK,128,17:25:00,3441.03,-08554.20,26771,08,8.52,-9*7F
10
Camcorders for balloons
•Hobbypartz $59 thumbdrive camcorder
Tachyon XC helmetcam
11
915 MHz telemetry
Maxstream (Digi)
9Xtend
- 1 Watt output
- 9600 baud or 115k baud
- Long range with yagi on
ground
Digi XBee Pro XSC
- Up to 100 mW out
-900 and 2400 MHz versions
-Great for wireless comms
between payloads
- With a high-gain yagi it’s
possible to directly link up to
the balloon during flight
12
915 MHz telemetry
Digi XBee Pro
- Serial data from the MMTXMT is sent to the XBee Pro
for payload to payload
comms or directly to the
ground
- Ground station end showing
XBee Pro mounted to the back
of an 8 dB patch antenna
13
915 MHz telemetry
-For improved range and
better pattern directly below
the balloon you can use a
“Nanowheel” antenna by
Olde Antenna Labs (sold by
www.hamtv.com)
-900 MHz rubber duck
shown for size comparison
14
Remote control your ground station
•Logmein.com
Remotely log
Onto your
Computer via
Logmein
Control your radio with:
Fldigi
Ham Radio Deluxe
MixW
MultiPSK
15
Hardware control – Iobridge.com
•Controls relays and sensors via Ethernet/Web connection
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Hardware control – Iobridge.com
•Internet-controlled AZ/EL Rotor via the Iobridge interface
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Field Day Balloon 2010
- Predicted a landing on
top of the Huntsville
Amateur Radio Club’s
Field Day site
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Field Day Balloon 2010
Huntsville Amateur
Radio Club members
watch as the balloon
parachutes down directly
across their field day site
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Field Day Balloon 2010
Missed landing on the
HARC Field Day site
by 0.75 miles
Landed right in the
middle of Lady Ann
Lake
Field Day
location
20
Field Day Balloon 2010
A
conveniently
placed kayak
saves the day
21