Just wondering can you pick up Short Wave signals very close to the transmitter?

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eastangliauk
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Just wondering can you pick up Short Wave signals very close to the transmitter?

Post by eastangliauk » 01 Jun 2015 17:03

Just wondering can you pick up Short Wave signals very close to the transmitter or do they go sky wave straight away?
Also how far do the Short Wave signals go before they start going sky wave?
Radios Tecsun PL398MP + PL-660 & JVC KD-G632 - Blaupunkt BPR-3 DAB+

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Julian Hardstone
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Re: Just wondering can you pick up Short Wave signals very close to the transmitter?

Post by Julian Hardstone » 01 Jun 2015 19:03

At shorter wavelengths, say below 30m, SW signals are normally beamed at a low elevation towards the target area, but in all directions there will be sufficient radiated power to give local reception well beyond the visible horizon; expect to hear within maybe 200 miles for typical SW Broadcast power.
At longer wavelengths, say above 60m, the main propagation mode is vertical incidence reflection from the D layer or F1 layer (IIRC) whereby the reflected signal will be stronger than the direct space wave at less than 10 miles. Apart from the 75m band, most broadcasts use a vertical beam in order to cover a radius of several hundred miles with relatively low tx powers.

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eastangliauk
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Re: Just wondering can you pick up Short Wave signals very close to the transmitter?

Post by eastangliauk » 01 Jun 2015 21:05

Thanks so it depends on which band your on.
I guess being on below 30m would be best.?
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Re: Just wondering can you pick up Short Wave signals very close to the transmitter?

Post by Tim Bucknall » 02 Jun 2015 10:22

i get wooferton groundwave here on 17 & 21mhz if it helps
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Julian Hardstone
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Re: Just wondering can you pick up Short Wave signals very close to the transmitter?

Post by Julian Hardstone » 03 Jun 2015 00:13

eastangliauk wrote:I guess being on below 30m would be best.?
"Best" for what? We were discussing propagation theory! If a band is 'open' for Dx you will hear more distant tx than local ones, and if it is 'closed' no one will be using it to transmit in your part of the world.

You've got a PL-600 , so just turn it on and tell us what you can hear! If you want to hear some fairly local tx on lower SW frequencies try for RAF volmet on 5450, though that will come day and night via ionospheric reflection unless you are close to Lancashire; ditto Shannon volmet on 5505 from the west of Ireland

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Re: Just wondering can you pick up Short Wave signals very close to the transmitter?

Post by Tim Bucknall » 03 Jun 2015 12:44

when i was a pirate our low power 6210 couldn't even be heard across town (1 mile -ish or maybe even less)
i expected this, but was slightly surprised that 4004khz wasn't much better for groundwave

I concur with Julians advice, and his bafflement :-)

ps: my wooferton groundwave reception was on an outdoor loop (ala 1530) if using a portable then expect much lesser distances
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