EFHW 40m long balloon antenna

EFHW 40m long balloon antenna details:
- Section1: 12m Spiderbeam mast
- Section2: 28m UL Dxwire (4g/m) suspended from a balloon (total weight 120g)
- Balloon is Sempertex 91cm latex balloon, inflated to 77cm, having roughly 229g of payload lift (Helium lift is around 266g and the balloon weights 37g).
- Using HiFloat gel to extend the float time of the balloon. Aim is to survive 2 full days (i.e. a contest weekend).
- 49:1 transformer is used, made from 2xFT240-31 ferrite toroids.
- Coax was around 20m long and there was a 1:1 choke just before the radio.
- The antenna was grounded next to the 49:1 transformer
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Measurements for Sempertex 91cm latex balloon filled with Helium (HiFloat used, kept outside ~4 degrees Celsius):
- at start - 220g payload lift
- after 22h - 205g payload lift
- after 42h - 180g payload lift
- after 48h - 150g payload lift (raining)
- after 54h - 174g payload lift (still a bit wet)
- after 68h - 110g payload lift
- after 73h - popped
Note: Good quality balloon, a bit expensive.
Measurements for Gemar 80cm latex balloon filled with Helium (HiFloat used, kept mainly indoors):
- at start 165g payload lift
- after 15h - 155g payload lift (indoors)
- after 22h - 152g payload lift (indoors)
- after 33h - 148g payload lift (indoors)
- after 57h - 130g payload lift (indoors) 79%
- after 84h - 110g payload lift (indoors)
- after 132h - 85g (indoors) 50%
- after 177h - 62gr (indoors)
Note: Usage shows the Gemar balloon to be very rugged and price is very good. My preferred choice at the moment.

[@plamentodorov2441]

Браво!

[@lz1jer]

Поздравления! В моя експеримент изпозвах 3 по-малки балона, които издържаха около седмица. Работих само на 160м FT8, 20W - Европа и Европейска Русия. Нямах добра, даже никаква радиална система, само заземяване. Тунерът се справи, използвах емайлиран проводник 0.2мм. Поздрави.

[@chavylevy7355]

Остана ми хелий и следващата събота ще пробвам с едножилна жица 0.4мм (1.1г/м). Искам да пробвам дали мога да достигна 80м височина за EFHW на 160 метра. Тъкмо има CQ WW 160 SSB, та ще има с кой да пробвам. Проблема е какво да се прави като им вятър. Мисля нещо подобно, но трябва да се тества:
ua-cam.com/video/DNGOhCnTz4M/v-deo.html