Dear Alex, LF Group,
At 04:18 PM 08/04/2002 +0000, you wrote:
When trying to recive RU6 signals I have hear someone similar DCF39 about
138.83 kHz. But delay between 'RTTY bursts'is not 10 sec. but about 18
sec. Sometimes the delay is about 4 sec. but not often. I wonder is this
stn DFC39 indeed?
Yes, that sounds like it - the data telegrams are not transmitted at equal
intervals
I copy this stn (audibaly) very nice at night time. I do not measure
S/N ratio but its seems to be 15 dB or more... My input filter (135.5 ..
137.8 kHz) reject 138.83 kHz about 10 dB. So real S/N is more 25 dB!
The ERP of DCF39 is about 40kW I think (+46dBW) - so the S/N with a 0dBW
ERP amateur signal should be about -21dB. Assuming this is in a bandwidth
of around 300Hz, you should in theory be able to copy QRSS with fairly long
dot lengths, such as 30s, over the same distance, if your RX has good
frequency stability.
Unfortunely I do not hear this stn in day time. Also I can not hear
it at evening (befor 01 or 02 local) because of very strong industrial
QRM (TV sets I think).
I think many of us have these problems...
I wonder also does DCF39 radiate all the time or part of time only?
Almost all the time - it occasionally goes QRT, probably just for maintenance.
Cheers, Jim Moritz
73 de M0BMU
| 