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Author Topic: Vertical/Horizontal/Groundwave/DF 12 June 2020  (Read 688 times)

Offline Brian

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Vertical/Horizontal/Groundwave/DF 12 June 2020
« on: June 12, 2020, 1928 UTC »
Unlikely to be a vertical antenna at that frequency. I agree about the power level, I guess lower than 100 watts. On again tonight.


edit by Ray : this was about Unid 3400 heard again
« Last Edit: June 13, 2020, 1051 UTC by Ray Lalleu »

Offline The Ether Hacker

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Re: Vertical/Horizontal/Groundwave/DF 12 June 2020
« Reply #1 on: June 12, 2020, 1939 UTC »
Unlikely to be a vertical antenna at that frequency. I agree about the power level, I guess lower than 100 watts. On again tonight.

I don't know what antenna is used at that station. What I meant was, one can get a decent local groundwave signal upto about 5 to 10 km around the lower HF bands with low power and a vertical, quarterwave monopole, shortened or inverted L .... but a horizontally polarized antenna will generally give very little local groundwave coverage.... maybe 1 or 2 km

I am getting the same signal strengths tonight as last night again.
Antennas: Multi-band doublet for 80 to 10m HF and vertical groundplane
RX: Kenwood R-2000
QTH: Northern England

Offline Brian

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Re: Vertical/Horizontal/Groundwave/DF 12 June 2020
« Reply #2 on: June 12, 2020, 2001 UTC »
Horizontal antenna will give a good ground wave for more than 10 miles. Trust me, I know  ;). Unfortunately the ITU have DF'd me to within about 12 miles and that's close enough for ground wave detection, should the local authorities want to pay me a visit. I always have the kettle on.

Offline The Ether Hacker

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Re: Vertical/Horizontal/Groundwave/DF 12 June 2020
« Reply #3 on: June 13, 2020, 0644 UTC »
Horizontal antenna will give a good ground wave for more than 10 miles. Trust me, I know  ;). Unfortunately the ITU have DF'd me to within about 12 miles and that's close enough for ground wave detection, should the local authorities want to pay me a visit. I always have the kettle on.

Sure, there is no particular maximum or minimum groundwave coverage. It depends on your TX power, your particular immediate local topography and signal absorption conditions, but a vertical will ALWAYS give a stronger groundwave on mediumwave and on the lower half of the shortwave spectrum.  Almost all AM Mediumwave broadcast stations, including Low power ones, have some sort of vertically radiating antenna to maximise groundwave, except high powered stations of the past who switched to horizontal night time antenna constructions for stronger skywave and reduced groundwave coverage.  I believe Radio Luxembourg 1440 khz used daytime and nighttime TX antennas and so did R.I.A.S (Rundfunk im Amerikanischen Sektor) - Berlin in the 20th century.  For maximum day and night time coverage on mediumwave.

My conclusion is that your local groundwave would have gone even further than 12 miles with more of your signal being vertically polarised under same conditions.... and yes, groundwave is easy to triangulate.
Antennas: Multi-band doublet for 80 to 10m HF and vertical groundplane
RX: Kenwood R-2000
QTH: Northern England

 

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