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Reply-To: rsgb_lf_group@yahoogroups.co.uk X-Yahoo-Newman-Property: groups-email-ff-m Content-Type: multipart/alternative; boundary="--------MB_8D0EA6E42B78181_864_7D4AE_webmail-m150.sysops.aol.com" ----------MB_8D0EA6E42B78181_864_7D4AE_webmail-m150.sysops.aol.com Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Hi Roger, =C2=A0 calculating ERP... =C2=A0 Using 1/r^3 from 10 m=C2=A0to the radiation field boundary at 0.8 km, we ge= t =C2=A0+72 - 3 * 38 dBuA/m =3D -42 dBuA/m, then proceeding=C2=A0with 1/r to 1 km and multiplying by 377 ohms =C2=A0H =3D -42 - 2 =3D -44 dBuA/m, E =3D=C2=A07.5 dBuV/m, deriving radiated power and ERP =C2=A0EMRP =3D=C2=A07.5 - 49.5 =3D -42 dBm =3D 63 nW, =C2=A0ERP =3D 115 nanowatts. =C2=A0 ... not much is it?=20 =C2=A0 Anyhow using very slow modes, you might be able to make several tens or eve= n 100 kilometers on daytime groundwave. =C2=A0 Best 73, Markus (DF6NM) =C2=A0 =C2=A0 -----Urspr=C3=BCngliche Mitteilung-----=20 Von: Roger Lapthorn <rogerlapthorn@gmail.com> An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>; rsgb_lf_group <r= sgb_lf_group@yahoogroups.co.uk> Verschickt: Di, 28 Jan 2014 12:28 pm Betreff: LF: 73kHz in the UK? Is my reading of the UK frequency allocation chart right?=20 One can operate without a licence in the old 73kHz band using licence-exemp= t inductive devices rules as long as the output is less than 72dBuA at 10m?= Not sure what sort of ERP this equates to. A few uW I assume? Perhaps someone can advise/confirm. 73s Roger G3XBM =C2=A0 ----------MB_8D0EA6E42B78181_864_7D4AE_webmail-m150.sysops.aol.com Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable  
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Hi Roger,
 
calculating= ERP...
 
Using 1/r^3= from 10 m to the radiation field boundary at 0.8 km, we get
 += 72 - 3 * 38 dBuA/m =3D -42 dBuA/m,
then procee= ding with 1/r to 1 km and multiplying by 377 ohms
 H =3D= -42 - 2 =3D -44 dBuA/m, E =3D 7.5 dBuV/m,
deriving ra= diated power and ERP
 EMRP = =3D 7.5 - 49.5 =3D -42 dBm =3D 63 nW,
 ERP = =3D 115 nanowatts.
 
... not muc= h is it?
 
Anyhow usin= g very slow modes, you might be able to make several tens or even 100 kilom= eters on daytime groundwave.
 
Best 73,
Markus (DF6= NM)
 

 

-----Urspr=C3=BCngliche Mitteilung-----
Von: Roger Lapthorn <rogerlapthorn@gmail.com>
An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>; rsgb_lf_group <r= sgb_lf_group@yahoogroups.co.uk>
Verschickt: Di, 28 Jan 2014 12:28 pm
Betreff: LF: 73kHz in the UK?


Is my reading of the UK frequency allocation chart right?

One can operate without a licence in the old 73kHz band using licenc= e-exempt inductive devices rules as long as the output is less than 72dBuA = at 10m? Not sure what sort of ERP this equates to. A few uW I assume?

Perhaps someone can advise/confirm.

73s
Roger G3XBM

 

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