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20m inductor values

"Chris Lantaff" #136 开云体育 Has anyone worked out the inductor values for 20m. I have a program somewhere but can't find it now that it's needed. ? Thanks, - Chris KE9YK
Arv Evans #137 开云体育 Chris KE9YK Use the calculator located here Select your core type, plug in the frequency and any one other value and it will spit out the inductance, turns, capacitance, etc. If duplicating the G0UPL design you can use that calculator to determine the impedance of his coils, then plug that back in for 20 meters and get the L, C, turns, etc. info very quickly. Arv K7HKL _._ On 09/17/2010 05:43 PM, Chris Lantaff wrote: toggle quoted message Show quoted text ? Has anyone worked out the inductor values for 20m. I have a program somewhere but can't find it now that it's needed. ? Thanks, - Chris KE9YK
Stephen Farthing #138 Guys, This may save you some time. The beacon design uses the standard harmonic output filter designs used by the GQRP club documented here?. So a good starting point will be the one for 20 meters. You might find that the 2n7000 will not put out much output power at 20 Meters, but hey, this is QRSS and we dont need much output power :-)... I hope to make a 20 meter version myself in the next week or so and will report back.... 72/3 de Steve G0XAR -- It is vain to do with more that which can be done with less.
"hanssummers2000" #139 Hi all This may save you some time. The beacon design uses the standard harmonic output filter designs used by the GQRP club documented here . So a good starting point will be the one for 20 meters. You might find that the 2n7000 will not put out much output power at 20 Meters, but hey, this is QRSS and we dont need much output power :-)... Please note people, that you may also need to reduce the value of the capacitors in the base/emitter of the Colpitts oscillator. They are 220pF in the 30m version. I think for 20m I think I would be tempted to start with a first guess of 150pF and see if that worked. 73 Hans G0UPL

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