форум Радиолюбительского ДВ портала > Прием на длинных волнах
VLF, very low frequency, 3kHz to 30kHz
rw3adb:
ебнаут дошел и до 6.47 кГц! -)
считаю, сие достойным, дабы быть запечетленным в истории у нас на форуме!
Ich habe ein kleines Weihnachtsgeschenk für Stefan!
The 75 character message received at 6470 Hz:
"HABE DEN MUT DICH DEINES EIGENEN VERSTANDES ZU BEDIENEN
- IMMANUEL KANT -"
by coherent summing of 7 daily transmissions.
Eb/N0 = -0.2 dB, BER 32.44%, constant reference phase.
List decoding rank: 1987053.
S/N: 26.14 dB in 36.9 uHz, -52.2dB in 2.5kHz.
Day Phase Eb/N0
2016-12-18 41.2 -5.5
2016-12-19 47.2 -10.1
2016-12-20 38.0 -8.2
2016-12-21 40.5 -10.1
2016-12-22 48.0 -11.0
2016-12-23 50.9 -8.8
2016-12-24 42.9 -12.2 (not used, skipped)
2016-12-25 46.6 -7.1
--
Paul Nicholson
--
rw3adb:
Очередные потуги Стефана по освоению VLF. на сей раз 5170 Гц.
Hi VLF,
It's time to come back to 5.17 kHz where i have been in the last kite
experiments 2010/2011. The best result was about 10 dB in 3.8 mHz in 904
km distance, detected by SQ5BPF. His website about this experiment is
still on the web,
http://www.lipkowski.org/~sq5bpf/dk7fc_20101023/index_en.html
In these kite tests my ERP was about 3 mW on 5170 Hz. But this was with
a 300m vertical antenna!
With my fixed antenna i can never radiate such strong signals. The
limiting factor is the coil which can handle 250 mA on that frequency.
The radiation resistance is about 210 uOhm, so the ERP will be up to 23
uW. So this is 20 dB weaker (oh, actually i expected it is even more
weaker). But on the fixed antenna it is no problem to transmit 100x longer!!
We will see what is possible on that band with such a low power. Who
wants to make a guess? :-)
But i'm not yet sure if i can resonate the antenna down there at all.
The plan is to use the small coil that was used for 6470 Hz. Inside the
coil there are 100 iron powder cores, shown here
https://dl.dropboxusercontent.com/u/19882028/VLF/20160415_155753.jpg and
here
https://dl.dropboxusercontent.com/u/19882028/VLF/20160415_163021.jpg I
want to replace (a few) of them by ferrite cores, many ferrite cores
"switched in parallel". I need to get the inductance down from 1.2 H to
2.0 H. So first the ferrite cores much provide a higher effective µr
(ur) which is no problem i guess. Secondly the must not saturate (to
much), which is the critical question here. We will see what happens...
It's the right time in the year for such a work and i think i can do a
first transmission on 58 km during this week...
73, Stefan
R1QBI:
Build a VLF transmitter and receiver.
Poular Elrctronics 1990 -7 стр.29-33.
https://yadi.sk/i/5ugsZIIk3NF9B6
ub3wbc:
Скидываю грабберы на дропбокс https://www.dropbox.com/s/nwrxdkezqgy84ni/xbm_grab.jpg?dl=0
https://www.dropbox.com/home/SPECTRAN
R1QBI:
--- Цитата: ub3wbc от 21 Июль 2018, 18:34:27 ---Скидываю грабберы на дропбокс https://www.dropbox.com/s/nwrxdkezqgy84ni/xbm_grab.jpg?dl=0
--- Конец цитаты ---
Какая звуковая карта используется?
Мой скрин:
Такой эфир чистый? Тогда где "Альфы"?
Навигация
Перейти к полной версии