Re: LF: 472kHz TX without an antenna: it gets better (701km with around 5mW ERP)

[Roger Lapthorn <rogerlapthorn@gmail.com>]

Yes I should try this Eddie and will do so later in the week as part of this experiment.

I have a couple of earth rods right outside the rear of the house and can connect to these rather than the pipes just inside the house. The other earth rod is at the bottom of the garden.

You may recall that when I tried this on VLF the results on earth-mode were well down, suggesting that the copper pipe connection is important. Mind you, the water pipes right outside in the road are NOT metal and do not have tracer wires either. It may well be different on 472kHz though if this is working as a loop; on VLF earth mode the way the signal is propagated is totally different.

73s

Roger G3XBM

On 6 January 2013 18:30, g3zjo <g3zjo@psk31.plus.com> wrote:

Roger

Great results.

Can you out of interest disconnect the House / great lump of capacitance, mains wiring, water pipes etc. Leaving just the 2 probes and top wire. It would be re-produce-able then

Eddie

On 06/01/2013 18:10, Graham wrote:

That's a  good  start  then Roger,  !

 

I  think it  could be visualised  as a    gradual  / gradient  , so the   top  wires  have the  max  current  in free  space  and the  return  path is  some  form of  diffused  large  cross  sectional  area     , you  could  model  it  on 2  meters  ..using  what  for  the  ground ... cardboard box , bin bag , water  and jar of cooking  salt , add  to  increase  conduction   ?

 

Could  be  simply  gain is from the  increased  amps  in the  top  radiator , so  the  model  would  be  quite  small  for 2  mtrs , kitchen  table  job !

 

.G..

From: Roger Lapthorn

Sent: Sunday, January 06, 2013 5:53 PM

To: rsgb_lf_group@blacksheep.org

Subject: Re: LF: 472kHz TX without an antenna: it gets better (701km with around 5mW ERP)

Well this is just about the only explanation that will make any sense Graham.

If so, I would expect some directivity and when I analyse the results after an overnight run we'll see if stations off the side of the "loop" are statistically weaker (compared with the Marconi vertical) than stations in the line of the "loop". If so, this would tend to support loop like operation. The DL-SWL and PA reports are roughly in the plane of the wire, but there are plenty of reports from other directions too.

Of course, here in the UK we have highly saturated ground - I have NEVER known East Anglia to be so waterlogged - so the effective loop area cannot be that great.

Anyone care to offer other suggested modes for this "non antenna"?

73s

Roger G3XBM

On 6 January 2013 17:42, Graham <g8fzk@g8fzk.fsnet.co.uk> wrote:

R,

 

I thought  it  was  established  that  the  ground  did  not  'exist'  for  some  20/40  feet  or more from the  surface  and  as  such, your  using a  loop  with the  bottom  wire   40  feet  lower than the  top  wire ?

 

This was the  principal  of  ground lying   Ae  .would  not  work  on  salt marshes  , but  for  normal  ground , lossey but  capable  of  supporting  radiation ?

 

G..

From: Roger Lapthorn

Sent: Sunday, January 06, 2013 5:28 PM

To: rsgb_lf_group@blacksheep.org ; rsgb_lf_group@yahoogroups.co.uk

Subject: LF: 472kHz TX without an antenna: it gets better (701km with around 5mW ERP)

OK, now I am totally amazed....

Just got a WSPR spot from DL-SWL in Germany (JO52hp) at 701km using just the earth electrode system on TX. Please someone, explain why this works as well as it does, especially considering my ERP must be around 5mW at best.

Incidentally G3XIZ is a colossal +7dB S/N on WSPR and I think Chris would be easily workable on CW using the earth electrode system.

73s

Roger G3XBM

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 http://g3xbm-qrp.blogspot.com/
http://www.g3xbm.co.uk
https://sites.google.com/site/sub9khz/
http://qss2.blogspot.com/

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 http://g3xbm-qrp.blogspot.com/
http://www.g3xbm.co.uk
https://sites.google.com/site/sub9khz/
http://qss2.blogspot.com/