|Subject:||Re: LF: DCF39 ERP and field strength|
|From:||Dick Rollema <[email protected]>|
|Date:||Mon, 15 May 2006 14:11:34 +0200|
In the web of Geri, DK8KW, can be seen that DCF39 ERP is 40KW (22KW EMRP), based on measurements made by Geri some years ago. For this radiater power corresponds, at 1800 Km, in function of inverse of distance, 58 dB(uV/m); last nigth I made measurement of 60 dB(uV/m), so I wonder if still DCF39´s power is the same as before, and if the previous theorical field strength, with no reflection loss, can be exceeded some times due to the several propagation factors involved.
I measure the field strength of DCF39 at 2078 microvolt/metre (66.35 dBµV) , as it is always at daytime.
The distance between my location and DCF39 is about 500 km. Using the graph for "LAND" (conductivity 0.03 S/m, dielectric constant 40) in CCIR Recommandation 368-7: GROUND-WAVE PROPAGATION CURVES FOR FREQUENCIES BETWEEN 10 KHz AND MHz I find the power of DCF39 to be 39.8 kW. This should be rounded to 40 kW of course. That this agrees so well with the 40 kW mentioned by Geri is pure coincidence, given the uncertainties involved.
73, Dick, PA0SE
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