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To All from PA0SE
Here are the results of my signal measurements
during the weekend
Time Call
Field strength Input RX
S-report Remark
UTC
dB(uV)/m dBm
Friday January 7
2328 CFH? (137 kHz RTTY)
27
-70 S9 + 3 dB
2329 Greek
RTTY 34
-63 S9 + 10 dB
2334 DCF139
73
-24 S9 + 49 dB
Saturday
January 8
0504 CFH? (137 kHz
RTTY) 27 -70
S9 + 3 dB
0508 Greek
RTTY 32
-65 S9 + 8 dB
0512 DCF139
65
-32 S9 + 41 dB
0748
DCF139 63
-34 S9 + 39 dB
0820
PA0LEG
26
-71 S9 + 2 dB
0827
G4GVC
13
-84 S7 + 1 dB
0830 CFH? (137 kHz
RTTY) 11 -86
S6 + 5 dB
0841
OE5ODL
-3
-100 S4 + 3 dB
0906
ON7YD 17 -80
S7 + 5 dB
0911 Greek
RTTY 15 -82
S7 + 3 dB
0913 DCF139 66
-31 S9 + 42
dB
0943 G6RO -3 -100 S4 + 3 dB
0948
ON6ND
28 -69
S9 + 4 dB
0958
DK8KW 12
-85 S7
1024 DL3FDO 6 -91 S6
1034
PA0BWL 23
-74 S8 + 5 dB
1045 G3OLB 6 -91 S6
1140
DCF139 64 -33 S9
+ 40dB
1218
DK5PU
7 -90
S6 + 1 dB
1238 G3AQC
8 -89 S6
+ 2 dB
1250 Greek
RTTY 15 -82
S7 + 3 dB
1254
G3XTZ 19
-78 S8 + 1 dB
1315 G3YXM 17
-80 S7 + 5 dB
1320
G3YXM 16
-81 S7 + 4 dB
1
1358
DF9IE
7 -90 S6
+ 1 dB
1436
DJ6FU 12
-85
S7
Sunday January 9
0824 CFH? (137 kHz
RTTY)
20
-77
S8 + 2 dB
0826 Greek
RTTY
19
-78
S8 + 1 dB
0828
DCF139
65
-32 S9
+ 41 dB
0841
G4GVC
13
-84
S7 + 1 dB
0858
ON7YD
19
-78 S8
+ 1 dB
0915 GI3PDN
-
- S3
(by ear) 2
1018 G3KEV 20
-77
S8 + 2 dB
1023
G3YXM
15
-82
S7 + 3 dB
1028
Greek
RTTY 24
-73
S9
1029 DCF139
64
-33 S9
+ 40 dB
1058
DJ9IE
19
-78 S8
+ 1 dB
1100
G3XDV 9
-88
S6 + 3 dB
1110
PA0BWL
24 -73 S9
Remarks
1. After Dave had lowered the centre of his
aerial from about 18 metres to 15 metres.
2. Report by ear:sent RST339; received RST 459.
Ray was too deep in the noise for measuring.
GI3PDN is my 64th station and GI is my 12th
country.
Method of measurement
I could not use my Wandel & Goltermann PSM-5
selective level meter. The needle jumps around too wildly for a proper reading
on CW (and they call CW Continuous Wave ...). Also its selectivity is
not sufficient.
Instead I applied a substitution
method.
The receiver is a Teletron LWF45.The output goes
to a passive audio filter; its bandwidth is 35 Hz on CW and 200 Hz on RTTY. The
output from the filter is fed to ex-WW II headphones type DLR 5 and to the
Y-input of an oscilloscope. The deflection is adjusted to a suitable value by
means of the manual gain control of the receiver (which has no AGC), being
careful not to overload the RX. Next a HP signal generator type 604B is
substituted for the aerial, tuned in for maximum signal and its output level
adjusted for the same deflection on the scope as produced by the received
signal. The signal strength in dBm is then read from the signal
generator.
I did use the selective level meter on the
carrier of DCF139 between bursts of data. The result was exactly the same
as found by the substitution method. A useful cross check.
I measured the signal strength of DCF139 with my
home made field strength meter in an open field near to our house where there no
underground cables, pipelines or other disturbing objects. I measured
1.66 mV/m, or 64 dB(uV). The input to the
receiver at that moment was
-33 dBm. So the field strength in dB(uV)/m
can be found by adding
(64 + 33) = 97 dB to the input of the receiver in
dBm.
For the S-report I applied the IARU
recommendation: S9 = -73 dBm and
1 S-point = 6 dB. I used the _expression_ (S +
dB) also below S9 to avoid loss of information due to rounding.
73, Dick, PA0SE
JO22GD
D.W. Rollema
V.d. Marckstraat 5
2352 RA Leiderdorp
The Netherlands
Tel. +31 71 589 27 34
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