At 06:40 20/01/00 -0000, G3YMC wrote:
Six months or so ago I regular copied IK5ZPV (and I5MXX) at 579. Lately his
signal has been much down, 549. Is this change in propogation or has there
been a change at his station?
I know that IK5ZPV runs lower power when it is raining (to prevent arcing).
But apart from that I have a 'day to day' signal strength variation on his
signal of over 10dB. I cannot give exact S-meter reports as my S-meter is
not calibrated for 136kHz but for me the signal to noise ratio is more
important than the absolute signalstrength (what is the use of receiving a
station at S7 when noise is S9). On a 'good night' both IK5ZPV and I5MXX
are up to 20dB S/N (solid armchair copy) the average (at a winternight) is
about 15dB S/N.
In practice this means that on a quite winternight noise is 'tagling' my
S-meter at about S1 and both stations are a S3 (average) to S4 (good). I
checked the S-meter (using a 1dB-step attenuator) and found out that S1 to
S3 is about 15dB while S1 to S4 is about 20dB. By ear I would give then a
589 report (good) or 569 report (average), last night I checked the
difference between my 2 ears but could not observe any (I'll have to check
a MD about that).
I have some filtering and attenuation between antenna and RX to reduce IM
products. Removing the filters and attenuators increases all signals with
about 15dB but then the whole band sounds like one boiling pot and only the
strong signals can be copied.
73, Rik ON7YD
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