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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.

A description of my home made field strength meter and its calibration can be found at www.picks.f9.co.uk/pa0se/htm or www.lwca.org/library/global/pa0se/fsm.htm.

73, Dick, PA0SE

JO22GD

D.W. Rollema

V.d. Marckstraat 5

2352 RA Leiderdorp

The Netherlands

Tel. +31 71 589 27 34

E-mail: d.w.rollema@freeler.nl

pa0se@amsat.org