Hello Jim, Am 07.07.2012 20:55, schrieb James Moritz: When you replace the existing inductor with a high-Q one, you will find that the loop gain of the circuit is increased due to the higher Q, and y
OK! Hans. All right. Well, meanwhile my VFO is ready, the output waveform is available as a low impedant rectangular voltage. But i have to choose the caps for getting and covering the right frequenc
Am 06.07.2012 09:31, schrieb Johan H. Bodin: Stefan, Jim is right as always. Ferrite is unusable in VFO inductors. I just wanted to add that Micrometals (== Amidon) Txx-6 has a slightly lower tempera
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 low
Clemens, MEK stands for "methyl-ethyl-ketone" and is also known as butanone. It is a rather strong organic solvent mainly used in industry. An alternative might be acetone. It is commonly available (
Clemens As Rick noted it's methyl-ethyl-ketone ... which is still readily available here in the states. Maybe it has a different name in DL. Here's some more info on making your own http://www.clifto
Stefan Great news and detail about your oscillator. Let us know when you take your last Breath !! MF, Another episode about my analog oscillator for MF story. After the hints from the LF group i have
Stefan, Jim is right as always. Ferrite is unusable in VFO inductors. I just wanted to add that Micrometals (== Amidon) Txx-6 has a slightly lower temperature coefficient than Txx-2. I have built suc
Hello Hans, I alreda y have a DDS from ELV, since several years. But this one has a sine output and needs a +- input volatge. So i added a DC/DC converter from 12V -> +-12V to the circuit. This DDS c
what about a huff&puff oscillator (http://www.hanssummers.com/huffpuff.html) ? 73, Rik ON7YD - OR7T LF, My first 500kHz TX used a huff/puff VFO and it was very stable - as long as the RF pickup in th
All you can do with thermal drift is heat the assembly to a temperature , where you can control the core temperature by ensuring the thermal gradient is steep enough not to be affected by the ambient
Hi Stefan, the W1VD link looks very nice,the dual gate mosfet is a very good buffer circuit to prevent pulling.Getting the best stability you probably won't manage in an evening but making it work wo
Hello Ha-Jo, Can you pull one of the xtals to cover the whole band? 73, Stefan Am 05.07.2012 20:57, schrieb [email protected]: Dear all, the only parts I have bought so far for MF (still
Stefan es co Try permability osc tuning like Collins use instead of variable condensers, maybe even a valve osc. de g3kev -- Original Message -- From: [email protected] Stefan Sch
Hello Stefan, The NE602 works very well as oscillator and delivers a clean and low noise signal. One of the main problem in building VFO's is the mechanical design. It can be done, but it is not triv
Hi stefam/Ha-Jo....when I did this I chose a pair of crystal that mixes to one end of the band then pulled one upwards and the other downwards simultaneously. There still is a slight drift problem bu
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
