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boundary="-1740643075-747203660-1317245423=:85953" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: ** X-Spam-Status: No, hits=2.5 required=5.0 tests=FORGED_YAHOO_RCVD,HTML_30_40, HTML_MESSAGE,NO_EXPERIENCE,TO_ADDRESS_EQ_REAL autolearn=no version=2.63 X-SA-Exim-Scanned: Yes Sender: owner-rsgb_lf_group@blacksheep.org Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rs_out_1@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false x-aol-global-disposition: G X-AOL-SCOLL-SCORE: 0:2:477376992:93952408 X-AOL-SCOLL-URL_COUNT: 0 X-AOL-SCOLL-AUTHENTICATION: mail_rly_antispam_dkim-m008.1 ; domain : yahoo.com DKIM : fail x-aol-sid: 3039ac1d60d64e83922c4ce4 X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none ---1740643075-747203660-1317245423=:85953 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable Hello Stefan,=0A=A0=0Ayes, this is what I planned to do.=0AAdditional 100 p= F should be enough for the NDB band, then with another parallel cap it shou= ld be possible to go to the 136 KHz band.=0ABest 73=0ADaniele=0A=0A=0A_____= ___________________________=0ADa: Stefan Sch=E4fer =0AA: rsgb_lf_group@blacksheep.org=0AInviato: Mercoled=EC 28= Settembre 2011 22:59=0AOggetto: Re: LF: Re: My first ferrite experiments= =0A=0A=0A Hi Daniele, =0A=0AI agree with Wolf's comments.=0A=0AAnother thin= g: If you add a (switched)=A0 cap of the same C value, you=0Awill come down= to the LF radio band and to the amateur band too. I took=0Astyroflex caps = in my RX antenna and got the mentioned Q. So then you=0Acan see/listen LF s= tations, if there are any ;-)=0A=0A73, Stefan/DK7FC=0A=0AAm 28.09.2011 21:0= 5, schrieb Daniele Tincani: =0AHello Stefan, =0A>=A0 =0A>this morning I=0Ar= eceived the litz wire and tried another build, using a 16 mm PVC tube=0Ato = enclose the 3 x ferrite rods. I wound 70 turns of litz (as good as I=0Acoul= d) and went to the test bench again to measure Q (please see the=0Aattached= picture). In fact, things have improved a bit. With the air=0Avarcap I'm u= sing for these tests, tuning can range from about 235 KHz=0Aup to about 978= KHz. Using nominal min/max valued of capacitor, this=0Agives approx L =3D = 670uH which is very good for my purposes. =0A>Unfortunately Q=0A- although = improved - is still quite low: about 104 @ 235 KHz, about 60=0A@ 978 KHz. = =0A>As I don't plan=0Ato try another build of the ferrite-cored coil, I can= only hope=A0that=0AQ=A0will improve further with shorter and better connec= tions with the=0Acapacitor. =0A>Many thanks to=0Ayou, Stefan, for the very = helpful suggestions! =0A>=A0 =0A>Best regards =0A>Daniele =0A>=A0 =0A>=0A> = =0A>Da: Stefan Sch=E4fer =0A>A: rsgb= _lf_group@blacksheep.org=0A>Inviato: Marted=EC 27=0ASettembre 2011 22:42=0A= >Oggetto: Re: LF: Re:=0AMy first ferrite experiments=0A>=0A>=0A>Hi Daniele,= =0A>=0A>Am 27.09.2011 17:15, schrieb Daniele Tincani: =0A>Hello Stefan, = =0A>>=A0 =0A>>> but maybe the Q is=0Areduced by the aluminium shield! =0A>= >Do you=0Athink the aluminium could be the problem or the distance between = the=0Acoil and the core? =0AThe wire shouldn't wound directly on the rod= . I have a PVC tube above=0Athe rod and so the wire is in a distance of abo= ut 3 mm to the rod. I=0Aused litz wire and got a Q of 485...=0A>=0A>=0A>I c= ould=0Areplace the aluminium tube with a plastic tube, if shielding is not= =0Anecessary, but this would not improve the Q if the problem is the gap=0A= between the coil and the core. =0AJust experiment what is the best solut= ion. But the aluminium shield -=0Aif used - should be thin and can be appli= ed above the winding in some=0Adistance. I know you have much QRM at home s= o probably an E field=0Ashield makes sense here. Anyway you will be bothere= d by the local=0Amagnetic QRM of course. =0A>I personally think that a shie= ld is not necessary if you are /p and far=0Aaway from man made noise. Then,= a higher Q helps more than the shield=0Aand a Q of 30!=0A>=0A>=0A>=A0 =0A>= >> Are the rods=0Agalvanically separated from each other by a thin plastic = tape? What=0Atype is the ferrite material? =0A>>Yes I=0Aput two layers of p= lastic tape on tips of each rod. The ferrite=0Amaterial is russian MU400HH.= =0AFine! I also use the same ferrite type and 55 turns. Your cap is sur= ely=0Athe best what you can use. So shorten the wires between L and C and= =0Ameasure the Q on 137 kHz. If it is still in the range of 30, i assume=0A= the shield causes high losses.=0A>Another idea: There is some conducting sp= ray available. Maybe this can=0Ahelp here? No experience with that, just a = spontaneous idea... =0A>http://it.farnell.com/_/kontakt-chemie-emv-35-200ml= /rivestimento-conductive-emv-35/dp/220115 =0A>=0A> =0A>=0A>73, Stefan/DK7= FC=0A> =0A>=0A> ---1740643075-747203660-1317245423=:85953 Content-Type: text/html; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable
Hello Stefan,<= /div>
 
yes, this is what I planned t= o do.
Additional 100 pF should be enough for the NDB= band, then with another parallel cap it should be possible to go to the 13= 6 KHz band.
Best 73
Daniele

D= a: Stefan Sch=E4fer <Stefan.Schaefer@iup.uni-heidelberg.de>= ;
A: rsgb_lf_group@blacksheep.orgInviato: Mercoled=EC 28 S= ettembre 2011 22:59
Oggetto: Re: LF: Re: My first ferrite experiments

=0A= =0A=0A=0A =0A=0A =0AHi Daniele,
=0A
=0AI agree with Wolf's comments= .
=0A
=0AAnother thing: If you add a (switched)  cap of the same= C value, you=0Awill come down to the LF radio band and to the amateur band= too. I took=0Astyroflex caps in my RX antenna and got the mentioned Q. So = then you=0Acan see/listen LF stations, if there are any ;-)
=0A
=0A73= , Stefan/DK7FC
=0A
=0AAm 28.09.2011 21:05, schrieb Daniele Tincani:= =0A
=0A
=0A
Hello Stefan,
=0A
 
=0A
this morning I=0Areceived the litz wire= and tried another build, using a 16 mm PVC tube=0Ato enclose the 3 x ferri= te rods. I wound 70 turns of litz (as good as I=0Acould) and went to the te= st bench again to measure Q (please see the=0Aattached picture). In fact, t= hings have improved a bit. With the air=0Avarcap I'm using for these tests,= tuning can range from about 235 KHz=0Aup to about 978 KHz. Using nominal m= in/max valued of capacitor, this=0Agives approx L =3D 670uH which is very g= ood for my purposes.
=0A
Unfortunately Q=0A- althou= gh improved - is still quite low: about 104 @ 235 KHz, about 60=0A@ 978 KHz= .
=0A
As I don't plan=0Ato try another build of the= ferrite-cored coil, I can only hope that=0AQ will improve furthe= r with shorter and better connections with the=0Acapacitor.
=0A=
Many thanks to=0Ayou, Stefan, for the very helpful suggestions= !
=0A
 
=0A
B= est regards
=0A
Daniele
=0A  
=0A

=0A
=0A
=0A
Da:=0AStefan Sch=E4fer <St= efan.Schaefer@iup.uni-heidelberg.de>
=0A A:=0Arsgb_lf_group@b= lacksheep.org
=0A Inviato: Marted=EC 27=0ASettembre 2011 22:42
=0A Oggetto: Re: LF: Re:=0AMy first ferrite experime= nts
=0A
=0A =0A
Hi Daniele,
= =0A
=0AAm 27.09.2011 17:15, schrieb Daniele Tincani:=0A
=0A
=0A
=0A
=0A
Hello Ste= fan,
=0A
 
=0A
> b= ut maybe the Q is=0Areduced by the aluminium shield!
=0A Do you=0Athink th= e aluminium could be the problem or the distance between the=0Acoil and the= core?
=0A
=0A
=0A
=0A =0AThe wire shouldn't wound directly on the rod. I have a PVC tube above= =0Athe rod and so the wire is in a distance of about 3 mm to the rod. I=0Au= sed litz wire and got a Q of 485...
=0A
=0A
=0A
=0A =
=0A
=0A
I could=0Areplace the aluminium tube with a plastic tube, if shie= lding is not=0Anecessary, but this would not improve the Q if the problem i= s the gap=0Abetween the coil and the core.
=0A
=0A =
=0A
=0A
=0AJust experiment what is the best so= lution. But the aluminium shield -=0Aif used - should be thin and can be ap= plied above the winding in some=0Adistance. I know you have much QRM at hom= e so probably an E field=0Ashield makes sense here. Anyway you will be both= ered by the local=0Amagnetic QRM of course.
=0AI personally think that = a shield is not necessary if you are /p and far=0Aaway from man made noise.= Then, a higher Q helps more than the shield=0Aand a Q of 30!
=0A
= =0A
=0A
=0A
=0A
=0A
 
=0A
> Are the rods=0Agalvanically separated from ea= ch other by a thin plastic tape? What=0Atype is the ferrite material?
=0A
= Yes I=0Aput two layers of plastic tape on tips of each rod. The ferrite=0Am= aterial is russian MU400HH.
=0A
=0A
=0A =0A
=0AFine! I also use the same ferrite type and 55 turn= s. Your cap is surely=0Athe best what you can use. So shorten the wires bet= ween L and C and=0Ameasure the Q on 137 kHz. If it is still in the range of= 30, i assume=0Athe shield causes high losses.
=0AAnother idea: There is= some conducting spray available. Maybe this can=0Ahelp here? No experience= with that, just a spontaneous idea...
=0A http://it.farnell.com/_/kontakt-chemie-emv-35-200ml/rivestimento-con= ductive-emv-35/dp/220115=0A
=0A
=0A =

=0A
=0A
=0A
=0A
=0A
=0A73, St= efan/DK7FC
=0A
=0A
=0A
=0A
=0A = =0A
=0A
=0A
=0A
=0A
=0A=0A =0A= =0A

---1740643075-747203660-1317245423=:85953--