AMSAT-LU Ham Radio High-Altitude Balloon to fly FM Repeater and SSTV


The system board containing RF transmitter module, receiver module, level adjustments, duplexer and antenna connector. Image credit LU7AA

AMSAT Argentina is pleased to announce that on Saturday, June 29, 2013 from 1400 GMT, weather permitting, it is planned to launch an amateur radio high altitude balloon FM repeater ‘Betty II’ from Victorica, La Pampa, 665 km. west of Buenos Aires, it is expected to travel east.

The 435.950/145.950 MHz FM repeater will be activated by a 123 Hz CTCSS subtone. The balloon can also transmit Slow Scan Television (SSTV) ROBOT-36 images from the onboard camera on 145.950 MHz. There is an APRS transmitter on 144.930 MHz.

It should be possible to access the balloon using a 2 watt FM handheld rig from 750 km away giving a theoretical maximum distance for two-way contacts of 1500 km.

AMSAT-LU May 2012Details and photos of the announcement and prior experiences in

Approval of ANAC (Argentina FAA)) had been granted by NOTAM (notice to air crew) .

For these experiments members of AMSAT-LU, LUSEX, project development group , are working together with Pampeano and QRM Belgrano Radio Clubs, APRS Group, etc.

Electronics is comprised of a voice UHF to VHF FM repeater with CW TLM, APRS, DTMF and SSTV. According to estimates balloon could reach 30,000 meters high, traveling for 3 hours, 150 km east of the launch site.

This would allow contacts between stations located in the provinces of Buenos Aires, Santa Fe, Entre Rios, Cordoba, Catamarca, Santiago del Estero, La Pampa, San Luis, Mendoza, San Juan, Rio Negro, Neuquen, Uruguay and Chile. (It is launched from the center of the country to facilitate greater participation). Coverage at

To receive the payload, if less than 750 km from launch site, only need is a handy or base FM receiver on 145.950 MHz for voice/sstv and 144.930 for APRS.

The repeater which is enabled via 123 Hz CTCSS subtone, receives 435.950 MHz FM voice (-112dBm, 0.56 uV) emitting 2W output simultaneously on 145.950 MHz.

AMSAT-LU picocubrPayload will also carry an emergency long duration APRS transmitter sourced by solar cells and supercapacitors as batteries.

To enable better utilization, it is suggested short QSOs (license, own locality, grid locator, received signal and short comments).

Simultaneous emits APRS 1200 baud at 144.930, and also in 145.950. The DTI symbol on APRS will change from a balloon ( /O ) during ascent to a slider ( /g ) during the parachute descent.

Will operate for 90 seconds voice, then a beep alerting the end of that time will make way for the issuance of APRS at different frequencies. Every five minutes CW TLM via telegraphy audio tones sends callsign LU7AA and height in meters, then repeat the cycle.

On 145.950 MHz SSTV images ROBOT-36 mode (36 seconds) will be emitted on demand showing what the balloon sees (Can be received, with either MIXW or RX-SSTV (recommended)).

Balloon will carry two GoPro TV cameras (one to ground and another to the horizon) that will record images and sound during flight and can be retrieved with the payload.

It will be live in APRS on every minute, including speed, height, internal and external temperatures and battery voltage.

Local georeferenced maps are available for UI-View in , to be renamed to pico2.inf .

The experiment on 435.950 MHz voice also receives and accepts DTMF user issued commands i.e. B * (DTMF keypad UHF handy) will return S5 … ….. on VHF CW 145.950, your signal strength received at balloon, if P10 that states S9 +10.

There are more commands that enable issuance of TLM in CW or APRS beacon and remote commands to drop payload, mode changes, control of timers, energy, power, enable SSTV, etc..

Additionally a VAISALA RS92SGP radiosonde emitting FM wide on 402.740/403 MHz has been added, which provides GPS location, pressure, winds, height, course, dwt point, temperatures, etc. Same data as daily collected by the National Meteorological Service.

Data can be received using an SDR dongle and sondemonitor program available as test for 21 days from internet.

On launch day/time AMSAT-LU will have one of his members on the Ezeiza Airport Traffic Control, acting as a contact between ANAC and AMSAT-LU, using VOR locations application, adapted from EOSS and available on .

Local frequencies coordination and announcements before and during flights will be 7095 kHz LSB + / -10 kHz and VHF frequencies of local repeaters in the area.

During flight 430.930 AMSAT-LU APRS will operate wide coverage Igate LU7AA-10, installed at the Investigation Center, besides a portable Igate close to launch site. Any area stations that can receive and provide bridge to the APRS network are welcome.

Being an experiment aimed at a next satellite, contacts made between stations thru this UV repeater will be considered valid and awarded upon request by AMSAT-LU Permanent Satellite Certificate, free and also applicable for license upgrades, see,,

Top 10 participants with the highest two-way contacts/distances sum thru repeater will be awarded with a special certificate. Send email with data filled on form QSOs with stations via the balloon including QRA Locators, QTR to RC QRM Belgrano before July 23.

All reports welcome. If you want or can organize or be part of launch teams, control, monitoring and recovery, operating as an independent station and capturing data, and / or want to join us in this adventure from the launch site can do it through an email to parapente arroba

We appreciate having read this information and forward if possible.

73, LU7AA, AMSAT-LU. aiming to the future by making present fun.
Email: info at

AMSAT Argentina

AMSAT-LU to launch amateur radio FM repeater to an altitude of 30 km


View of communications experiment: Below is the plate of the repeater. Top left is the SSTV camera and top right is the GPS receiver module. Image credit LU7AA

On Saturday, March 23 at 1400 UT AMSAT-LU plan to launch a High Altitude Balloon (HAB) carrying a 435.950/145.950 MHz FM repeater, a SSTV transmitter on 145.850 MHz and an APRS transmitter on 144.930 MHz.

The 145.850 MHz SSTV ROBOT-36 mode images will be transmitted in real time showing the view from the balloon. The images can be displayed by using free software such as MMSSTV.

Since 145.850 MHz is the input frequency for the amateur radio satellite SO-50, part of the experiment will be a link between the balloon and the satellite with SO-50 retransmitting the SSTV images on 436.7950 MHz over a far wider area.

At an altitude of 30 km the FM repeater, which uses a 123 Hz CTCSS tone, could have a range of up to 750 km.

AMSAT-LU have issued the following announcement:

Continue reading

AMSAT-LU Balloon Launch May 19

LU7AA brings news that on Saturday May 19 from 11hs-LU on (GMT-3), a free Balloon UV Repeater will fly from the city of General Pico (Airport), Province of La Pampa, Argentina, 571 Km west of Buenos Aires City. See details and photos

Given administrations requests by Amsat Argentina, launch is authorized and appropiate NOTAM (NOTification to AirMen) had been issued and granted by National Civil Aviation Administration.

Contest & Prices: first 10 station making the most distance & contacts will receive special certificate, top winner will receive a UHF/VHF handy.

Payload will operate as an UHF to VHF crossband repeater, with CW tlm, APRS location and SSTV emissions in local and space frequencies.

According estimates Balloon could reach 100,000 feet height, traveling from 50 to 100 miles towards east.

Thus allowing contacts between stations located in provinces of Buenos Aires, Santa Fe, Entre Rios, Cordoba, Catamarca, Santiago del Estero, La Pampa, San Luis, Mendoza, San Juan, Rio Negro, Neuquen, Uruguay & Chile. (Launch is from Argentina Geo-Center to permit higher participation). See coverage map on and estimated trajectory in .

For these experiences, Amsat-LU works with and it is thankful to hams of Radio Clubs of Gral.Pico, QRM Belgrano, APRS Group and amsat-LU members development team as well as those who have actively participated and sent their reports in previous events.

More information at

Several flown experiments have been successfully operated during 2011/12 in manned-gliders, airplanes, captive and free Balloons allowing operational & practice for hams contributing to platform validaton of LUSEX satellite (LU Satellite EXperiment) on development by Amsat Argentina. More on

In order to monitor the payload (if you are within 400 miles of launch area) you need just an FM receiver either handy or base, in 145.950 for repeater and/or 144.930 for APRS. The repeater, that is activated via 123 Hertz subtone, operates receiving voice FM in 435.950 kHz (-112dbm, 0,56 uV) and emits with 2W the received audio live on 145.950 kHz.

Simultaneously APRS data will be sent in Packet at 1200 bauds in 144.930, and also in 145.950.

The DTI APRS symbol would change from a Balloon (/O) during the ascent to a glider (/g) during parachute descent.

Payload would operate as voice repeater activated by 123 Hz subtone during 1 minute, a warning bip at 40 seconds will indicate telemetry is coming, which is emitted if the repeater is not in use, if in 20 seconds more voice repeater still in use a two bips will be heard signaling that short APRS packages will begin in the different frequencies, also every 5 minutes CW (telegraphy with tones of audio) with CQ + callsign (LU7AA), sequence#, ext. and int. centigrade temperatures and voltage of batteries, after which the cycle will repeat.

Experiment will also emit SSTV pictures in ROBOT-36 (36 seconds) in real time, showing what glider/Balloon sees. Every 5 minutes during ascent/descent and more spaced at high altitudes. (It can be received among others with MIXW, MMSTV & RX-SSTV ).

To study propagation and allow DX station to listen, balloon will also carry a 150 mW CW 7021 Khz transmitter, emiting callsign, sequence, external and internal temperatures and battery voltage.

Payload would also carry on board two TV cameras (one towards earth and another towards horizon) recording video and sound during the flight. These captured videos could be recovered when payload is recovered.

APRS trajectory could be seen every minute, including speed, height, external and internal temperatures and 7.2v battery voltage using UI-View (download from the UI-View official site on and/or to see/follow from Internet connecting to or locally via Packet at specified frequencies.

There are georeferenced Maps for UI-View in,
Download and place them in directory Program Files/Peak Systems/UI-View32/MAPS and rename .txt file to .inf.

The experiment in 435.950 KHz besides voice, receives and accepts DTMF sequences commands on demand, I.E. sending B* (DTMF with handy keyboard on UHF) will return S5 … ….. in 145,950 VHF CW, reporting in CW signal strength received from your station, if S9+10 will returns P10.

There are also DTMF commands qualifying emission of CW tlm or APRS beacon or SSTV emission, commands that allows remote release of payload, mode changes, timers control, energy, power, etc.

Frequencies for previous coordination, announcements and flights will be 7090 Khz LSB +/-10 Khz and local repeaters.

During the flights will remain active wide coverage AMSAT-LU APRS Igate LU7AA-10 on 144.930 and 430.930 KHz, operating from the Constituyentes Investigation Center transferring whatever is received towards Internet.

For being an experiment oriented to a next satellite, the contacts made between stations via this payload will be considered valid for the recently announced permanent, gratuitous and applicable Satellite Certificate that AMSAT-LU and RClub QRM Belgrano grants, more info on

During the Balloon flight, amateur groups will chase the payload, aiming to locate and recover. Trapping ventures holds on this activity, as in the case of the Pampero 15 Balloon sent from San Miguel del Monte which landed in the middle of the Magdalena’s state prison … See

All reports welcome. If you wish or can organize or want be part of control, or like to pursuit and recovery, or like operating and capturing data as an independent station, and/or wishes to join us personally in this adventure from the launching places email us to parapente at

We appreciate reading of this information and thankful if distribution possible.

73, LU7AA, Amsat-LU, aiming at the future by making the present funny.
Email: info at