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The original message has been attached to this so you can view it (if it isn't spam) or label similar future email. If you have any questions, see the administrator of that system for details. Content preview: Stefan As others have pointed out "6" material is about the best for VFO circuits. Ferrite, especially very high perm material is quite inferior. For securing turns I've found 'old fashioned' polystyrene coil Q dope to be a good choice. Doubt that it is sold anymore in the current 'scaredy cat world' ... but you can make your own. See http://www.radiobanter.com/showthread.php?t=149757 . Also a recipe there for Napalm should you need any of that ;~) [...] Content analysis details: (1.5 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at http://www.dnswl.org/, no trust [76.96.62.32 listed in list.dnswl.org] 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (jrusgrove[at]comcast.net) -0.0 T_RP_MATCHES_RCVD Envelope sender domain matches handover relay domain -0.0 SPF_PASS SPF: sender matches SPF record 1.5 AXB_XMAILER_MIMEOLE_OL_4379D AXB_XMAILER_MIMEOLE_OL_4379D X-Scan-Signature: ac0f6ff1af52b6036ac1f4fe0c2bd52c Subject: Re: LF: RE: Analog oscillators Content-Type: text/plain; format=flowed; charset="ISO-8859-15"; reply-type=response Content-Transfer-Encoding: 8bit X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.3 required=5.0 tests=NO_REAL_NAME 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: 0:2:462658848:93952408 X-AOL-SCOLL-URL_COUNT: 0 x-aol-sid: 3039ac1d410b4ff6f8f42398 X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none Stefan As others have pointed out "6" material is about the best for VFO circuits. Ferrite, especially very high perm material is quite inferior. For securing turns I've found 'old fashioned' polystyrene coil Q dope to be a good choice. Doubt that it is sold anymore in the current 'scaredy cat world' ... but you can make your own. See http://www.radiobanter.com/showthread.php?t=149757 . Also a recipe there for Napalm should you need any of that ;~) Jay W1VD WD2XNS WE2XGR/2 ----- Original Message ----- From: "Stefan Schäfer" To: Sent: Friday, July 06, 2012 10:17 AM Subject: Re: LF: RE: Analog oscillators > Hi Roelof, > > Another interesting information which is new for me. Thank you. I think many of us have learned a > bit from the topic. > > I thought about using super glue to fix the winding on the core. > > Or is this not to be recommended for some reason?. > > I will use a T50-6 then. This will take a few days until i have it on hand, unfortunately. > > 73, Stefan > > Am 06.07.2012 09:39, schrieb Roelof Bakker: >> Hello Stefan, >> >> A FT-37-43 ferrite toroid is not suitable for a VFO as you found. >> Powdered iron cores from Amidon are much better in this regard. >> From the common available parts -6 material has the lowest temperature coefficient, >> -7 is slightly better: >> >> T-50-2: 95 ppm/C >> T-50-6: 35 ppm/C >> T-50-7: 30 ppm/C >> >> The temperature coefficient does not vary with the size of the toroid. >> >> There are tricks to achieve mechanical stable windings on a Toroid. >> One is to wind it as tight as you can and than place the coil in boiling water for 10 minutes. >> This removes the mechanical stress and the winding settles down. >> >> 73, >> Roelof, pa0rdt >