Offline KevAmiga

  • *
  • Posts: 26
  • Round and round we go.
    • View Profile
HF Radio Signals, Propagation and DX.
« on: April 15, 2019, 11:16:21 AM »
Morning all :)

Have had a few spare hours this weekend so have been performing some HF Radio experiments, mostly looking at time of day propagation however this lead me into thinking... How would the FE guys explain what i'm seeing here. In the RE model its pretty straight forward.

So to set the picture, 7.074mhz is the frequency in use, using a mode called FT8. What FT8 is, in a nutshell, is a Data mode where radio transceivers controlled by PC's (doesnt need to be connected to the internet) exchange information back and forth, signal strength, location, etc. This can then be seen using a website called PSK Reporter (https://pskreporter.info).

So anyway, the question. At the moment, the HF "bands" are pretty flat, meaning comms are difficult due to the sun spot cycle. We are at flat bottom at the moment, causing Ionospheric "lulls" (Can read about it here : https://www.electronics-notes.com/articles/antennas-propagation/ionospheric/hf-propagation-basics.php if interested). What this means is, to best of my understanding, the ionosphere isn't reflecting HF frequencies well.

So - my observations. Using FT8 this weekend I can see my signal being picked up, mostly around Europe. Nothing local, nothing much further. I can put this down to the fact that, as the earth is a globe, my signal cannot "bend" and relies on reflection back down to earth. If the earth was indeed flat, I would not require any bouncing of signals as such? The only thing in the way would be mountains, buildings etc but being on a high ASL myself, this would help. But what REALLY adds the heat to the fire with this one, is all of a sudden, boom, i can be heard in the states, Russia, Antarctica, etc due to changes in the atmosphere. And then... as quickly as it comes,,, it goes.

Anyone else have any thoughts or experiences themselves? Happy to go further into FT8 if anyone is interested, or provide some times / my callsign for anyone wanting to see how the propagation works on PSK Reporter.

Kev

Offline KevAmiga

  • *
  • Posts: 26
  • Round and round we go.
    • View Profile
Re: HF Radio Signals, Propagation and DX.
« Reply #1 on: April 17, 2019, 08:44:18 AM »
Did a bit more FT8 last night, chasing the shadow (certain bands work better in the evening)... still hard to think how this would happen in the FE world.

Some good contacts from the UK down to Australia, Portugal, all on low power :)

Offline JCM

  • *
  • Posts: 156
    • View Profile
Re: HF Radio Signals, Propagation and DX.
« Reply #2 on: April 17, 2019, 04:44:05 PM »
I think you may be surprised by the FE reaction to this.  This will be used as evidence for flatness, not a globe Earth.  The justification is that obviously a curved Earth you shouldn’t be able to conceptually bounce the signal far at all.  On a flat Earth the bounce makes a lot of sense you will hear.  As far as differences in sunspot that difference is the same for both models and proves nothing as different conditions allow a further bounce.  Again, this will be used against the globe Earth, the farther the bounce the stronger the flat Earth argument, after all, how do you bounce a signal the other side of a globe?!   It also props up the idea that satellite signals are bounced off the ionosphere and aren’t coming from actual Earth orbiting satellites.

Offline KevAmiga

  • *
  • Posts: 26
  • Round and round we go.
    • View Profile
Re: HF Radio Signals, Propagation and DX.
« Reply #3 on: April 19, 2019, 07:01:58 AM »
Hey JCM, thanks for the reply.

So, my thoughts are :

1. I don't see why on a FE the bounce would make more sense? On a FE you wouldnt need to, you could aim your signal at the "horizon" and your away, no need for angle of attack at all.
2. Bouncing around the globe is based on the fact the layers within the atmosphere are also round, and thats where the bouncing occurs. (Read : "https://www.sws.bom.gov.au/Educational/5/2/2 ), 

3. Bouncing generally only affects HF and below. Satellite signals are generally in the GHZ range and require line of sight to work. 1575.42 MHz for GPS for example. Those signals, if sent from the ground would simply penetrate straight into space.

So here's another example of how we know this happens. When working modes like FT8 on HF, i'm in the UK and my signal was being received in Australia, and Iran, all sorts. But people in Scotland cant hear me. Neither can those in London, and the signal passes directly over them (in the F or E regions of the atmosphere, not at ground level). Hence the curve :)

Cheers!

Kev

Edit : So here's a quick propagation report based on stations receiving my signal this morning.



Signals again received in Australia... but shot directly over everyone else?
« Last Edit: April 19, 2019, 07:10:56 AM by KevAmiga »

Offline KevAmiga

  • *
  • Posts: 26
  • Round and round we go.
    • View Profile
Re: HF Radio Signals, Propagation and DX.
« Reply #4 on: December 20, 2019, 02:21:22 PM »
Little bump, in-case anyone wants to discuss :)

Offline somerled

  • *
  • Posts: 319
    • View Profile
Re: HF Radio Signals, Propagation and DX.
« Reply #5 on: December 20, 2019, 08:56:04 PM »
A good internet search will show you that the atmosphere is not transparent to radio waves.
Bouncing a signal of the ionosphere/dome will be easier than line of sight since the atmosphere is only a thin layer which decreases in density rapidly as altitude increases.

BillO

Re: HF Radio Signals, Propagation and DX.
« Reply #6 on: December 22, 2019, 05:09:55 PM »
A good internet search will show you that the atmosphere is not transparent to radio waves.
This is not true.  A better internet search will show you that the atmosphere is transparent to wavelengths from about 3cm to about 10m.  Which covers a lot of radio frequencies. The OP was talking about 7mHz - that is a wavelength of around 43cm.  The atmosphere is transparent to that wavelength.

Offline KevAmiga

  • *
  • Posts: 26
  • Round and round we go.
    • View Profile
Re: HF Radio Signals, Propagation and DX.
« Reply #7 on: December 22, 2019, 09:14:01 PM »
A good internet search will show you that the atmosphere is not transparent to radio waves.
This is not true.  A better internet search will show you that the atmosphere is transparent to wavelengths from about 3cm to about 10m.  Which covers a lot of radio frequencies. The OP was talking about 7mHz - that is a wavelength of around 43cm.  The atmosphere is transparent to that wavelength.

Not quite.

7Mhz is approx 40meters.

Offline KevAmiga

  • *
  • Posts: 26
  • Round and round we go.
    • View Profile
Re: HF Radio Signals, Propagation and DX.
« Reply #8 on: December 22, 2019, 09:16:56 PM »
A good internet search will show you that the atmosphere is not transparent to radio waves.
Bouncing a signal of the ionosphere/dome will be easier than line of sight since the atmosphere is only a thin layer which decreases in density rapidly as altitude increases.
Well that all depends on the wavelength in use. If you look above, i posted a picture from the good old internet which explains it a bit.

Im actually sat here now listening on 7mhz... quite a few stations coming in this evening :)

BillO

Re: HF Radio Signals, Propagation and DX.
« Reply #9 on: December 22, 2019, 10:01:36 PM »
A good internet search will show you that the atmosphere is not transparent to radio waves.
This is not true.  A better internet search will show you that the atmosphere is transparent to wavelengths from about 3cm to about 10m.  Which covers a lot of radio frequencies. The OP was talking about 7mHz - that is a wavelength of around 43cm.  The atmosphere is transparent to that wavelength.

Not quite.

7Mhz is approx 40meters.
What's a factor of 100 between friends?  That'll teach me to do arithmetic in my head ::)

Offline KevAmiga

  • *
  • Posts: 26
  • Round and round we go.
    • View Profile
Re: HF Radio Signals, Propagation and DX.
« Reply #10 on: December 23, 2019, 11:24:13 AM »
A good internet search will show you that the atmosphere is not transparent to radio waves.
This is not true.  A better internet search will show you that the atmosphere is transparent to wavelengths from about 3cm to about 10m.  Which covers a lot of radio frequencies. The OP was talking about 7mHz - that is a wavelength of around 43cm.  The atmosphere is transparent to that wavelength.

Not quite.

7Mhz is approx 40meters.
What's a factor of 100 between friends?  That'll teach me to do arithmetic in my head ::)

Haha true :)

In this instance though, would have made a big old difference :)

Offline somerled

  • *
  • Posts: 319
    • View Profile
Re: HF Radio Signals, Propagation and DX.
« Reply #11 on: December 23, 2019, 03:27:37 PM »
A good internet search will show you that the atmosphere is not transparent to radio waves.
Bouncing a signal of the ionosphere/dome will be easier than line of sight since the atmosphere is only a thin layer which decreases in density rapidly as altitude increases.
Well that all depends on the wavelength in use. If you look above, i posted a picture from the good old internet which explains it a bit.

Im actually sat here now listening on 7mhz... quite a few stations coming in this evening :)

It will affect all wavelengths to varying degrees - higher frequecy more interference .Atmosphere hinders 7mhz signals - that's classed as a HF wave . That good old picture needs the bottom line straightening - the dome bits ok though ho ho. The  sun's interference on radio signals is a good indicator of  electrical interference of the local sun imo. Enjoy your listening to the signals reflecting from the dome .

BillO

Re: HF Radio Signals, Propagation and DX.
« Reply #12 on: December 23, 2019, 09:06:31 PM »
In this instance though, would have made a big old difference :)
Very true.  But my point about how incorrect it is to say the atmosphere is not transparent to radio signals still stands.

Offline KevAmiga

  • *
  • Posts: 26
  • Round and round we go.
    • View Profile
Re: HF Radio Signals, Propagation and DX.
« Reply #13 on: December 24, 2019, 08:35:45 AM »
A good internet search will show you that the atmosphere is not transparent to radio waves.
Bouncing a signal of the ionosphere/dome will be easier than line of sight since the atmosphere is only a thin layer which decreases in density rapidly as altitude increases.
Well that all depends on the wavelength in use. If you look above, i posted a picture from the good old internet which explains it a bit.

Im actually sat here now listening on 7mhz... quite a few stations coming in this evening :)

It will affect all wavelengths to varying degrees - higher frequecy more interference .Atmosphere hinders 7mhz signals - that's classed as a HF wave . That good old picture needs the bottom line straightening - the dome bits ok though ho ho. The  sun's interference on radio signals is a good indicator of  electrical interference of the local sun imo. Enjoy your listening to the signals reflecting from the dome .

Interesting. Doesn't explain it though.

If the earth was flat... my "aim at the horizon" signal would ALWAYS get there. That wouldn't hit any "dome", or "atmosphere", just direct line of sight, no?

Offline KevAmiga

  • *
  • Posts: 26
  • Round and round we go.
    • View Profile
Re: HF Radio Signals, Propagation and DX.
« Reply #14 on: December 24, 2019, 08:36:38 AM »
In this instance though, would have made a big old difference :)
Very true.  But my point about how incorrect it is to say the atmosphere is not transparent to radio signals still stands.

Indeed. Transparent to smaller wavelengths that can pass through it, reflective (on times) to those low enough to bounce off it.

Offline KevAmiga

  • *
  • Posts: 26
  • Round and round we go.
    • View Profile
Re: HF Radio Signals, Propagation and DX.
« Reply #15 on: May 04, 2022, 02:37:46 PM »
Never did get an answer on this.

*

Offline RonJ

  • *
  • Posts: 2615
  • ACTA NON VERBA
    • View Profile
Re: HF Radio Signals, Propagation and DX.
« Reply #16 on: May 04, 2022, 06:15:04 PM »
Your evidence of a round earth using HF radio propagation isn’t quite right.  On both the flat earth and globe earth models it would be possible for a radio signal to be bounced off the ionosphere and returned to the earth.  There wouldn’t be any significant differences between the two.  Using the flat earth model a radio signal could bounce between the ionosphere and the earth multiple times until it reached the edge and then would go off into space never to be heard again.  On a globe earth the signal could bound back & forth around the globe and return to the same location.
Years ago, while living in the USA I could occasionally hear Russian stations using CW (morse code) with a definite echo in their signal.  If you used your beam antenna and turned it to the North the signal would peak up.  You could also rotate the antenna 180 degrees and again it would peak up.  Clearly there was a short path signal and a long path signal.  One signal coming in via the shortest path on a globe earth and another signal from the same station but coming in from the opposite direction from the longer path around the globe.  One signal would be delayed from the other because of the difference in distances and would produce an echo.  This kind of phenomena wouldn’t be possible on a flat earth. 
The sunspot cycle doesn’t make it easy to observe this kind of thing these days but will improve in the future.  Unless the FET can show how electro-magnetic waves can be bent around in a circle in the horizontal plane the theory is deficient.     
You can lead flat earthers to the curve but you can't make them think!

*

Offline Tron

  • *
  • Posts: 465
    • View Profile
Re: HF Radio Signals, Propagation and DX.
« Reply #17 on: July 28, 2022, 11:41:10 AM »
Hey JCM, thanks for the reply.

So, my thoughts are :

1. I don't see why on a FE the bounce would make more sense? On a FE you wouldnt need to, you could aim your signal at the "horizon" and your away, no need for angle of attack at all.

2. Bouncing around the globe is based on the fact the layers within the atmosphere are also round, and thats where the bouncing occurs. (Read : "https://www.sws.bom.gov.au/Educational/5/2/2 ), 

3. Bouncing generally only affects HF and below. Satellite signals are generally in the GHZ range and require line of sight to work. 1575.42 MHz for GPS for example. Those signals, if sent from the ground would simply penetrate straight into space.

So here's another example of how we know this happens. When working modes like FT8 on HF, i'm in the UK and my signal was being received in Australia, and Iran, all sorts. But people in Scotland cant hear me. Neither can those in London, and the signal passes directly over them (in the F or E regions of the atmosphere, not at ground level). Hence the curve :)

Cheers!

Kev

Edit : So here's a quick propagation report based on stations receiving my signal this morning.



Signals again received in Australia... but shot directly over everyone else?

Kev I made this map which represents the signals received from your UK transmission.   It looks spherical like what you might expect from line of sight transmission on a flat earth, but i'm not sure why they didn't pick up your signal further north.   

The US/Russia Station transmissions on this map are to address Ron J's observations..



« Last Edit: July 28, 2022, 01:10:10 PM by Tron »
From the surface Earth looks flat.  From space Earth looks round.  Now what?

*

Offline Tron

  • *
  • Posts: 465
    • View Profile
Re: HF Radio Signals, Propagation and DX.
« Reply #18 on: July 28, 2022, 11:59:56 AM »
Years ago, while living in the USA I could occasionally hear Russian stations using CW (morse code) with a definite echo in their signal.  If you used your beam antenna and turned it to the North the signal would peak up.  You could also rotate the antenna 180 degrees and again it would peak up.  Clearly there was a short path signal and a long path signal.  One signal coming in via the shortest path on a globe earth and another signal from the same station but coming in from the opposite direction from the longer path around the globe.  One signal would be delayed from the other because of the difference in distances and would produce an echo.  This kind of phenomena wouldn’t be possible on a flat earth. 
The sunspot cycle doesn’t make it easy to observe this kind of thing these days but will improve in the future.  Unless the FET can show how electro-magnetic waves can be bent around in a circle in the horizontal plane the theory is deficient.   

Ron - I mapped out your location in the US when you heard transmissions from Russia (see map in previous post). Keep in mind this is a South Centered FE Map.

I can't explain why you heard transmissions from the north facing antenna faster and without an echo.  I'd think a more direct signal would be received from the south?   :'(

I also don't assume that signals on a FE would bounce off the Ionosphere and into space.  All the layers of the atmosphere are curved with higher altitudes as you approach the equator (that's RE confirmed).  So, maybe the Russian transmission took a different bouncy path to your location?  Not sure if they can follow circular paths around the dome or what not. 
From the surface Earth looks flat.  From space Earth looks round.  Now what?

*

Offline J-Man

  • *
  • Posts: 1326
  • "Let's go Brandon ! I agree" >Your President<
    • View Profile
Re: HF Radio Signals, Propagation and DX.
« Reply #19 on: July 28, 2022, 05:27:05 PM »
We've been spraying chemtrails heavily since the early 1970's, just after the fake moon landing.  Flat Earth with dome catching the nano- metal particles in the concoction. This acts as the so called fake satellites. Bounce data and a proliferation of data towers everywhere.
What kind of person would devote endless hours posting scientific facts trying to correct the few retards who believe in the FE? I slay shitty little demons.