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  • Alexander Knochelquantensalat@astrodon.social
    May 27, 2025, 7:01 AM

    Preliminary #hamradio Announcement:

    Balloon 70cm SSTV experiment on June 25 in Weinheim with special call DF70UKW

    On June 25, we will, weather permitting, launch a weather balloon in Weinheim @DL0WH carrying student-built payloads.

    Apart from LoRaWAN-experiments, we will test our prototype of an SSTV module transmitting live pictures on 70cm FM. We will announce the QRG(s) and SSTV Mode!

    Stay tuned and tune in, send us a report!

    A group of people launching a white weather balloon on a large lawn, blue sky and some trees in the far back
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Replies

  • Alexander Knochelquantensalat@astrodon.social
    May 27, 2025, 7:15 AM

    #hamradio

    p.s. The time will probably be between 12:00 and 14:00 CEST, and we will probably be using the special callsign

    DF70UKW

    celebrating our 70th UKW ham radio conference this year, so tune in, catch a picture and send us a report!

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  • vu2tumvu2tum@mastodon.radio
    May 27, 2025, 11:26 PM

    @quantensalat @DL0WH Wish you a successful launch.
    Please share more details if available. What will be the expected footprint of this balloon? Will hams outside DL be able to receive? If yes, I shall QSP to VU hams.

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  • Alexander Knochelquantensalat@astrodon.social
    May 28, 2025, 4:54 AM

    @vu2tum @DL0WH Hi, thanks for your interest, it's a ballon that, if all goes well, rises to about 32-34 km and has a diameter of 7-8m when it bursts, payload is about 700 grams.

    TX power is 1 watt into a dipole, which ordinarily wouldn't get you very far, but with line of sight and only air in between, I see no reason why we shouldn't be received at several 100s km if QRM is low, the ISS only has a few watts and are really loud when overhead 400km away. I would imagine southwestern neighbors of DL/ such as F/ have a shot, I/, HB*/, OE/, LX, OK maybe. OZ/, SP/ are maybe a bit far. Maybe also depends on how well we design our antenna. VU is impossible on UHF unfortunately since the horizon at maximum burst altitude is only 600 km away

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  • vu2tumvu2tum@mastodon.radio
    May 28, 2025, 5:06 AM

    @quantensalat @DL0WH I have a HF WSPR monitoring station and pico balloons show up every few days. These one, the last several months and their Tx is about 200mW The two major differences I see here are 700g payload vs ~35g and UHF vs HF.
    If the balloon drfits south east, and VU is under its footprint, 1W is quite good to receive. Best wishies !

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  • Alexander Knochelquantensalat@astrodon.social
    May 28, 2025, 5:10 AM

    @vu2tum @DL0WH A student of mine put WSPR @ 10m and 40m on a ballon and analyzed the range(altitude) dependence. On 10m it was almost exactly to the horizon on that day, on 40m it was already worldwide, so UHF is the important factor, will very probably only travel to the horizon unless some sort of freak propagation occurs.

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