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During our stay in India, Stefan's DFCW signal
could be detected almost on a regular basis. The little RX was usually located
in a palm-leave hut at the edge of the farm, a place normally
dedicated to meditation and becoming part of a cosmic positive energy flow
- and thus quite appropriate for intercepting subtle electromagnetic
vibrations from a distant friend ;-)
Best 73,
Markus (DF6NM)
Sent: Tuesday, February 14, 2012 11:55 AM
Subject: LF: DK7FC received in South India
We are currently in Kerala (India), and I have
taken along an LF receive setup consisting of active E-probe, FiFI-SDR IQ
receiver, and my netbook. Due to other activities, limited notebook battery life
and lack of internet connectivity, it is not possible to run a continuous
grabber from here, but I could arrange a few receive sessions, either around
local midnight or before sunrise (details given below).
At night, HGA 135.43 kHz was up to 58 dB SNR, and
both HGA and DCF were clearly audible. HGA could still be detected at about 12
dB SNR at midday. So far, signals from DK7FC were positively received on three
occasions. I have asked Stefan to temporarily QSY 0.2 Hz down to evade an
erratically appearing local line. Besides DK7FC, the attached screenshot from
last night may also have a weak trace on 136174.3 and perhaps another on
136172.8 Hz (note that frequency scales are offset by about 0.22 Hz due to
residual LO error).
Depending on our travel group's schedules, I may be
able to run a couple more evening sessions in the days to come. Unfortunately we
have to walk to the next village for internet access, but I can hook up with
Stefan by mobile phone for announcements and immediate feedback. We intend to go
back to DL on Feb. 24th.
Best 73,
Markus (VU/DF6NM)
Details:
Location: MJ89GP, 9.65 N 76.53 E, in the village of Sreekandamangalam,
about 5 km north of Kottayam, Kerala, India, time zone UT + 5:30,
antenna:
Eprobe 40 cm wire in a palm-leave shed, simple BF245C preamp,
receiver:
FiFi-SDR (modified frontend, temperature stabilized Si570), LO 135 kHz (0.22 Hz
low),
computer: akoya netbook, internal soundcard 11025 IQ /s, SpecLab FFT
21 mHz, 10s /pix.
Receive sessions:
12-02-07 morning 0:09-01:28
noise blanker not
enabled
0:20-0:55: 136172.0+-0.075 DK7FC T...M
12-02-08 morning 0:49-02:00
noise blanker not enabled
local carrier
on 136172.1
nil DFCW
12-02-08 daytime 6:38-7:06
HGA about 12 dB SNR
QRM lines 136172.1,
136074.0
12-02-08 evening 16:04-17:32:
noise blanker enabled
136171.8 +-0.075
DK7FC "O" up to 20 dB SNR, HGA abt 58 dB SNR
12-02-13 evening 17:39-19:12:
noise blanker enabled
17:39-19:12
136171.8 +-.075 DK7FC "O" 15-20 dB SNR
17:45-18:03, 18:58-19:05
136174.3 unid "T" < 10 dB SNR
18:57-18:59 136172.8 unid
"T"
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