Hello Veino,
2. Due to ITU and EBU requirements we are engaged
to use relative unit dB(mW), after some problems
with our customers we have adopted "dBmW" instead
of normal "dBm". In fact ITU regularly uses "dBW".
Is the use of "dBu" based on some agreements?<
thank you very much for your valuable measurements. I recall we already
discussed the misleading unit we see from time to time. The only reason I
was using dBu (not dB microVolt but dBu) is that the relatively cheap
selective level meters I use (Praecitronic MV6/62 and Siemens D2108) were
originally used for level measurements on telephone lines, with 0 dBu =
0.775 Volt at 75 Ohm. In the meantime I have found a way to measure the
actual field strength by means of a 1m diameter loop, so I know the
relationship between my receiver signal strength and the field strength (0
dBu equivalent to 108 dBuV/m) , so I recently changed the information in my
logbook on my homepage into dB microVolt/m. I believe that this, together
with the CCIR curve give a better indication about the propagation modes
and probably the ERP someone uses -- at least in direct comparison.
Best 73
Geri, DK8KW (W1KW)
P.S.: hope you catch my signal one of these days, I would love to have a
figure on my field strength in OH ... pretty small, as I suppose, with 30
mW ERP
P.S.2: Veino, a question to you as the expert: are the CCIR curves valid
for ERP or EIRP? The curves state that they were calculated for a power of
1 kW from a "short monopole" antenna. Does this mean, we are comparing our
curves to 1kW EIRP? Is the 40 kW radiated power of DC39 that Gamal and I
measured (in comparison to the CCIR curves) EIRP or ERP?
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