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• Ilmari Reality Check # 3
• Additional notes

SUPER ILMARI REALITY CHECK meeting number 3

2002-10-31 klo 17:30 - 21:00 SA

ANRITSU, ESPOO

Log notes:

• Log notes by Matti, OH1MQK..
• Heikki, OH2LH, presented a picture of 80m Tx.
  • ~ 0.5 W out
  • ~ 1.8 W in
  • [FIXME:pic]
• OH1LRY presented his 400 bps Phase-3-style telemetry frame producing test hardware. [FIXME:pics]
• Radar reflector [FIXME:pic] by Juha, OH2LKV, mass 53g
• Cross-dipole mid point construction by gluing with poly-urethane proved to be unexpectedly difficult. Lab tests continue with test articles, not with actual surface coppered steel tapes.
• OH2AUE presented also a 1.3 GHz big-wheel antenna made from semi-rigid cable. It is heavy. An all-aluminium version needs to be made.
• When afterwards asked, Michael, OH2AUE, said:
  • 2m translator receiver antenna is a cross-dipole
  • 70cm translator transmit antenna is a cross-dipole
  • 70cm APRS-transmitter antenna is a bigwheel (aluminium elements)
  • 70cm translator and APRS antennas are about 2m distant from each other at the opposite sides of the system box.
  • 1.3 GHz ATV antenna is a bigwheel (aluminium elements)
  • 80m antenna is some conductive wire with likely a Fuchs feed.
• Kauto, OH2LFM, noted that finnish aviation regulations (OPS M-1) state, that at a "light-weight unmanned balloon" no cable/tether shall have tensile strength in excess of 230 Newtons. (This limits a bit of for example the 80m antenna wire material!)
• At the meeting also hardware made at LAB-2 session: [FIXME:pics]
• Matti, OH1MQK, presented his Ilmari Housekeeper Unit thoughts
  • (Block diagram. Processor: MMC2114, frequency source DDSes: AD9834.)
  • Wider general discussion about IHU, and other redundant solutions
    • Decided to take "Ihme-IHU" into one of the projects
    • Keeping alternates at hand just in case the "Ihme-IHU" does not complete/does not work/is not trusted.
    • Alternates are: MIM to produce APRS, a PIC to receive DTMF commands.
  • IHU et.al. functionality requirements were listed as:
    • Mission Abort
      • DTMF command
      • Flight-box, e.g. GPS location detects moving outside permitted flight area in N successive location fixes. (Coordinate area in integer minutes for the calculation.)
      • Timer (6h from the beginning of the flight, or some such.)
    • ATV-Xmitter control
      • DTMF command
      • Flight-box, e.g. GPS location detects presense inside of permitted transmit area in N successive location fixes. (Coordinate area in integer minutes for the calculation.) One fix outside the permitted area closes the transmitter. eN:
      • Battery voltage
      • Timer (15/45 sec on/off ?)
      • Transmitter overtemperature/overcurrent ?
    • Transponder control
      • DTMF command
      • Flight-box, e.g. GPS location detects presense inside of permitted transmit area in N successive location fixes. (Coordinate area in integer minutes for the calculation.) One fix outside the permitted area closes the transmitter. eN:
      • Battery voltage
      • Timer ? (total flight-time)
      • Transmitter overtemperature/overcurrent ?
    • 70cm APRS beacon
    • 3.6 MHz CW/MFSK16 beacon
• Flight planning was discussed about
  • Kauto, OH2LFM reported about Finnish Civil Aviation Administration contacts.
  • Was noted, that it would be neat to raise as fast as possible to around 20 km (15 km?) and then stop there, or slowly raise higher. Going too hight (30-40 km) is not good, as there is a steady rapid wind in there (30-40 m/s.)
• Heikki, OH2LH, had stripped out various solenoids from some junk pile source. We shall investigate the use of these for the mission abort.
• Insurance matter: Radio Amateur Technical Society (www.RATS.fi) received an offer for an insurance for these flights at about price 100€ per year, which covers damages caused by the falling payload to some hapless where it might hit...
• Michael, OH2AUE, had bought (at a price he refused to reveal) two CMOS color video cameras with integrated "sort-of-optics". Cameras weight circa 7 grams each, and draw circa 40 mA/5V.
• For ATV TX frequency OH2AUE, and OH2LAK decided: 1282 MHz
• Translator was decided to ivert so that input is at 2m, and output is at 70 cm. That way system local APRS transmiter would not jam translator receiver input.
• For the translator input OH2AUE and OH2LAK decided: 145.224 MHz (± 35kHz)
• Primary flight target is fall (late september) 2003.
• A test flight (tethered-balloon, or some such.) spring/summer once with batteries, possible multiple with "ground-feed".
• Summer camp to have advertising, and demoes, a tethered-balloon with ground-fed electricity ?
• Interviews of Pauli, OH2DV, has been done, and partially published at history section.
• Next meeting location:
  2002-11-28 klo 17:30-21:00 SA
  PC-SuperStore:n auditorio, Konala, Helsinki