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From: G0MRF@aol.com
Message-ID: <54e.19e7c.31cdd05a@aol.com>
Date: Fri, 23 Jun 2006 19:16:42 EDT
To: rsgb_lf_group@blacksheep.org
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Subject: Re: LF: RE: Top-fed LF antenna idea
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In a message dated 23/06/2006 17:22:09 GMT Standard Time,  
j.r.moritz@herts.ac.uk writes:

Dear  Peter, LF Group,

As I recall, G0MRF's first trans-atlantic transmission  was done from the top
of a tower block with a down-sloping wire as "top  loading" - Perhaps David
would care to fill in the  details...

Cheers, Jim Moritz
73 de  M0BMU


Hello Jim / Peter.
 
I thought of the transatlantic contact when I read your post. However the  
comparison to the EH antenna is a difficult one to make. In my case I was trying 
 to construct a center loaded dipole using 250 foot elements, or about 12  
degrees at 136k, with the feed point perhaps 180 feet above  ground.  In the 
event, the dipole proved very difficult to resonate and I  eventually settled for 
paralleling the two 250 ft wires and feeding them  against the several 
kilometres of copper water pipe running through the  building.  That worked very 
nicely with good QRSS3 signals visible in VO1  with RF down to 300W at the TX 
site.
Sadly that building was demolished 2 years ago, so no opportunity for  
another visit.
 
_http://www.g0mrf.freeserve.co.uk/atlantic.htm_ 
(http://www.g0mrf.freeserve.co.uk/atlantic.htm) 
 
Unfortunately I never did manage to get my dipole working.  However, 6  years 
later my homebrew N2PK vector network analyser is nearing completion and  
later this summer I hope to 'borrow' some land on very poor earth and finally  
put up a full size dipole and make some serious measurements. (The poor earth is 
 a key factor in the master plan! ) Will it work? - who knows! Certainly the  
scale model on 21MHz positioned 50mm above my lawn made it to a rather  
incredulous amateur in Romania.
 
Regards
 
David  G0MRF
 
 
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<DIV>
<DIV>In a message dated 23/06/2006 17:22:09 GMT Standard Time,=20
j.r.moritz@herts.ac.uk writes:</DIV>
<BLOCKQUOTE style=3D"PADDING-LEFT: 0px; MARGIN-LEFT: 0px"><FONT=20
  style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
=3D2>Dear=20
  Peter, LF Group,<BR><BR>As I recall, G0MRF's first trans-atlantic transmis=
sion=20
  was done from the top<BR>of a tower block with a down-sloping wire as "top=
=20
  loading" - Perhaps David<BR>would care to fill in the=20
  details...<BR><BR>Cheers, Jim Moritz<BR>73 de=20
M0BMU<BR></FONT></BLOCKQUOTE></DIV>
<DIV></DIV>
<DIV>Hello Jim / Peter.</DIV>
<DIV>&nbsp;</DIV>
<DIV>I thought of the transatlantic contact when I read your post. However t=
he=20
comparison to the EH antenna is a difficult one to make. In my case I was tr=
ying=20
to construct a center loaded dipole using&nbsp;250 foot elements, or about 1=
2=20
degrees at 136k,&nbsp;with the feed point perhaps&nbsp;180 feet above=20
ground.&nbsp; In the event, the dipole proved very difficult to resonate and=
 I=20
eventually settled for paralleling the two&nbsp;250 ft wires and feeding the=
m=20
against the several kilometres of copper water pipe running through the=20
building.&nbsp; That worked very nicely with good QRSS3 signals visible in V=
O1=20
with RF down to 300W at the TX site.</DIV>
<DIV>Sadly that building was demolished 2 years ago, so no opportunity for=20
another visit.</DIV>
<DIV>&nbsp;</DIV>
<DIV><A=20
href=3D"http://www.g0mrf.freeserve.co.uk/atlantic.htm">http://www.g0mrf.free=
serve.co.uk/atlantic.htm</A></DIV>
<DIV>&nbsp;</DIV>
<DIV>Unfortunately I never did manage to get my dipole working.&nbsp; Howeve=
r, 6=20
years later my homebrew N2PK vector network analyser is nearing completion a=
nd=20
later this summer I hope to 'borrow' some land on very poor earth and finall=
y=20
put up a full size dipole and make some serious measurements. (The poor eart=
h is=20
a key factor in the master plan! ) Will it work? - who knows! Certainly the=20
scale model on 21MHz positioned 50mm above my lawn made it to a rather=20
incredulous amateur in Romania.</DIV>
<DIV>&nbsp;</DIV>
<DIV>Regards</DIV>
<DIV>&nbsp;</DIV>
<DIV>David&nbsp; G0MRF</DIV>
<DIV>&nbsp;</DIV>
<DIV>&nbsp;</DIV></FONT></BODY></HTML>

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