From Newsgroup: uk.tech.broadcast

I live near Glasgow. I sometimes listen to Radio Caroline on 648 kHz
out of curiosity. I always understood that propagation depended on
hours of darkness. Usually there is no signal at all during daylight
and a reception of variable quality at night. Last week I tried in the afternoon and the reception was surprisingly good (I could clearly
make out 'Whiter Shade of Pale'). Any explanation?
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From Newsgroup: uk.tech.broadcast

On 22/11/2025 12:59, Scott wrote:

I live near Glasgow. I sometimes listen to Radio Caroline on 648 kHz
out of curiosity. I always understood that propagation depended on
hours of darkness. Usually there is no signal at all during daylight
and a reception of variable quality at night. Last week I tried in the afternoon and the reception was surprisingly good (I could clearly
make out 'Whiter Shade of Pale'). Any explanation?

The D-Layer which is present during the day, absorbs MF which is why you
can't hear MF during the day.

So either something stopped the D-Layer forming, or there was an
alternative mode of propagation, perhaps auroral reflection?


Dave
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From Newsgroup: uk.tech.broadcast

On Sat, 22 Nov 2025 15:40:59 +0000, David Wade <g4ugm@dave.invalid>
wrote:

On 22/11/2025 12:59, Scott wrote:

I live near Glasgow. I sometimes listen to Radio Caroline on 648 kHz
out of curiosity. I always understood that propagation depended on
hours of darkness. Usually there is no signal at all during daylight
and a reception of variable quality at night. Last week I tried in the
afternoon and the reception was surprisingly good (I could clearly
make out 'Whiter Shade of Pale'). Any explanation?

The D-Layer which is present during the day, absorbs MF which is why you >can't hear MF during the day.

So either something stopped the D-Layer forming, or there was an
alternative mode of propagation, perhaps auroral reflection?

Excuse my lack of knowledge but do you mean that you can get the
aurora (borealis) during the day but not see it because of the
daylight, but it can still be present and affect radio propagation?
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From Newsgroup: uk.tech.broadcast

On 22/11/2025 15:51, Scott wrote:

On Sat, 22 Nov 2025 15:40:59 +0000, David Wade <g4ugm@dave.invalid>
wrote:

On 22/11/2025 12:59, Scott wrote:

I live near Glasgow. I sometimes listen to Radio Caroline on 648 kHz
out of curiosity. I always understood that propagation depended on
hours of darkness. Usually there is no signal at all during daylight
and a reception of variable quality at night. Last week I tried in the
afternoon and the reception was surprisingly good (I could clearly
make out 'Whiter Shade of Pale'). Any explanation?

The D-Layer which is present during the day, absorbs MF which is why you
can't hear MF during the day.

So either something stopped the D-Layer forming, or there was an
alternative mode of propagation, perhaps auroral reflection?

Excuse my lack of knowledge but do you mean that you can get the
aurora (borealis) during the day but not see it because of the
daylight, but it can still be present and affect radio propagation?

Exactly. The ionisation occurs 24 hours of the day, you just can't see
it in daylight. On the other hand in Winter, when the levels of sunlight
are low, I can see it is possible that the D-Layer doesn't fully form
and there is some MF sky wave. There are other anomalies that can occur.
Which is why Radio "DX ing" remains popular. you never know what you are
going to hear...

Dave



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From Newsgroup: uk.tech.broadcast

Op 22-11-2025 om 16:40 schreef David Wade:

On 22/11/2025 12:59, Scott wrote:

I live near Glasgow. I sometimes listen to Radio Caroline on 648 kHz
out of curiosity. I always understood that propagation depended on
hours of darkness. Usually there is no signal at all during daylight
and a reception of variable quality at night. Last week I tried in the
afternoon and the reception was surprisingly good (I could clearly
make out 'Whiter Shade of Pale'). Any explanation?

The D-Layer which is present during the day, absorbs MF which is why you can't hear MF during the day.

So either something stopped the D-Layer forming, or there was an
alternative mode of propagation, perhaps auroral reflection?

Dave

The D-layer absorbs MF ?
you can't hear MF during the day ?

You hear nothing on MF during the day?

I have no problems with
648 Caroline
693 BBC Radio 5
1089 Talksport
and a few low power stations from the Netherlands
in house next to the PC.

I live in the centre of NL near Utrecht.

Rink
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From Newsgroup: uk.tech.broadcast

On 23/11/2025 13:05, Rink wrote:

The D-layer absorbs MF ?

The D-layer of the ionosphere attenuates MF, see https://en.wikipedia.org/wiki/Ionosphere#D_layer.

you can't hear MF during the day ?

No. You can hear MF, as long as the signal after attenuation by the
D-layer is still strong enough. At night (without the D-layer), MF
signals reach much larger distances.

You hear nothing on MF during the day?

No, that's incorrect. During the day you will not be able to hear long-distance signals, e.g. signals from several hundreds km away or
even crossing the Atlantic, due to attenuation by the D-layer.

Regards,
Uli
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From Newsgroup: uk.tech.broadcast

On 22.11.2025 12:59 Uhr Scott wrote:

Last week I tried in the afternoon and the reception was surprisingly
good (I could clearly make out 'Whiter Shade of Pale'). Any
explanation?

In winter, MW skywave is sometimes audible in daytime.

E.g. Solt 540 kHz Hungary (often called Budapest on the dial) is
audible on the Twente WebSDR all the time in winter.

http://websdr.ewi.utwente.nl:8901/fullday/
--
kind regards
Marco

Send spam to 1763812784muell@stinkedores.dorfdsl.de

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From Newsgroup: uk.tech.broadcast

Op 23-11-2025 om 13:37 schreef Ulrich Onken:

On 23/11/2025 13:05, Rink wrote:

The D-layer absorbs MF ?

The D-layer of the ionosphere attenuates MF, see https://en.wikipedia.org/wiki/Ionosphere#D_layer.

you can't hear MF during the day ?

No. You can hear MF, as long as the signal after attenuation by the
D-layer is still strong enough. At night (without the D-layer), MF
signals reach much larger distances.

You hear nothing on MF during the day?

No, that's incorrect. During the day you will not be able to hear long-distance signals, e.g. signals from several hundreds km away or
even crossing the Atlantic, due to attenuation by the D-layer.

Regards,
Uli

Thank you, Uli.
You described exactly how I think it is.

My questions were for David Wade, but he does not react.

Rink

----------------

Op 22-11-2025 om 16:40 schreef David Wade:

On 22/11/2025 12:59, Scott wrote:

I live near Glasgow. I sometimes listen to Radio Caroline on 648 kHz
out of curiosity. I always understood that propagation depended on
hours of darkness. Usually there is no signal at all during daylight
and a reception of variable quality at night. Last week I tried in the
afternoon and the reception was surprisingly good (I could clearly
make out 'Whiter Shade of Pale'). Any explanation?

The D-Layer which is present during the day, absorbs MF which is why

you can't hear MF during the day.

So either something stopped the D-Layer forming, or there was an

alternative mode of propagation, perhaps auroral reflection?

Dave

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