tag:blogger.com,1999:blog-7590176649168185428.post4639494054664462616..comments2024-03-27T17:14:31.032-04:00Comments on SolderSmoke Daily News: What Coil for the Polyakov Input Circuit? How to calculate a coil value for resonance. Bill Mearahttp://www.blogger.com/profile/07662500663603350847noreply@blogger.comBlogger7125tag:blogger.com,1999:blog-7590176649168185428.post-40225549506125631292022-08-15T01:03:36.431-04:002022-08-15T01:03:36.431-04:00Bill - the problem is that I've used different...Bill - the problem is that I've used different frequencies. I used 3.4 and 7.5 as an example. If you plug in your 3.23 and 13.01 to my formula you'll find it works. 73 Davidg3ryphttps://www.blogger.com/profile/16046620963176934079noreply@blogger.comtag:blogger.com,1999:blog-7590176649168185428.post-18293404014010703622022-08-14T23:54:52.147-04:002022-08-14T23:54:52.147-04:00Not our man Vladimir :)
Vasily Polyakov, Soviet fi...Not our man Vladimir :)<br />Vasily Polyakov, Soviet fighter pilot on film: <br /> @ 43: 14, https://youtu.be/0frbo09ocFU,<br />The Secret Air Skirmishes Of The Cold War | Shot Down Over The Soviet Union | Timeline <br />(1960s spy planes post-Gary Powers episode).Dex ZL2DEXhttps://www.blogger.com/profile/02696039554118623314noreply@blogger.comtag:blogger.com,1999:blog-7590176649168185428.post-28565916036625107632022-08-14T18:42:52.899-04:002022-08-14T18:42:52.899-04:00Andreas -- I'm reluctant to provide a schemati...Andreas -- I'm reluctant to provide a schematic for this, because so much depends on what you have on hand for the coil and the variable capacitor. Just follow the guidance for stability: Solid construction, NP0 fixed caps, an air core coil... Good luck. 73 Bill Bill Mearahttps://www.blogger.com/profile/07662500663603350847noreply@blogger.comtag:blogger.com,1999:blog-7590176649168185428.post-69527340373173142882022-08-14T18:40:17.676-04:002022-08-14T18:40:17.676-04:00I may be missing something re the "LC factor&...I may be missing something re the "LC factor" but, are you sure about this OM? My variable capacitor has a minimum capacitance of 23pf. With a 4.97uH coil it resonates at 14.885 MHz (too high!). The minimum capacitance is 23 pf. With a 4.97uH coil it resonates at 3.7014 Mhz (again, too high). With a 6.5 uH coil, the tuning range with this cap is 3.23 to 13.01 MHz. Are these calculations wrong? 73 Bill Bill Mearahttps://www.blogger.com/profile/07662500663603350847noreply@blogger.comtag:blogger.com,1999:blog-7590176649168185428.post-34862160614230132092022-08-14T00:53:16.586-04:002022-08-14T00:53:16.586-04:00The LC factor for a given frequency is 25330/(F*F)...The LC factor for a given frequency is 25330/(F*F) where L is inductance in uH, C is capacitance in pF and F is frequency in mhz.<br />Thus the LC factor for 3.4mhz is 2191 and the LC factor for 7.5mhz is 450. The difference is 1741. If we have a variable capacitor with 350pf swing then 1741/350 = 4.97 (uH) and the minimum capacitance at 7.5mhz = 450/4.97 = 90.5.g3ryphttps://www.blogger.com/profile/16046620963176934079noreply@blogger.comtag:blogger.com,1999:blog-7590176649168185428.post-36730226578547907002022-08-12T22:27:02.667-04:002022-08-12T22:27:02.667-04:00https://www.n6qw.com/Resurrection_Radio.htmlhttps://www.n6qw.com/Resurrection_Radio.htmlAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-7590176649168185428.post-69669310441266615682022-08-11T15:59:33.771-04:002022-08-11T15:59:33.771-04:00Dear Bill & Pete, with the current endeavours ...Dear Bill & Pete, with the current endeavours in temp stabilized VFOs in mind and the nouveau hardware defined radio spirit on the blog, I wonder whether there's a good suggestion for a 3.5 MHz VFO for the Polyakov DCR :) THXAndreashttps://www.blogger.com/profile/07843884057829704710noreply@blogger.com