G'day Markus, just a quick clarification - it wasn't me, it was Dale VK1DSH that transmitted the famous packet received in France. Since that incident, we changed our WSPR frequency to comply with th
Hi Alan, Here is my thinking. Let's assume an Rground of 18 ohm. The loss of the 220 Q inductor is 9 ohm, making the antenna impedance about 27 ohm. The Rrad is tiny, about 0.322 ohm. The calculated
Hi Eike, I think others have actually done this, isn't this the "envelop elimination and restoration" technique? In any case, my answer is that I don't know :-) I am just a beginner and my objective
Hi Markus, I have suggested to the local VK group to switch to radiated rather than wasted (LOL) power :-) Staying on a different frequency slot may be at the end what we will do. It seems that 475.7
Hi Roger and Graham, thanks the the replies, I have now changed my TX power to +27dBm. The efficiency of the antenna is not constant, as the Rloss changes after a rain, but at least +27dBm is closer
Here in VK we are also allowed 5 W, however, if my antenna efficiency calculations are correct, I need an order of magnitude more power to get even close to 5 W radiated. Such an amplifier will cause
For those not familiar with Class-E, I can control the power output of a transmitter by the Vcc I use. The power output is proportional to the square of the voltage, so by reducing the voltage by SQ
Hi Stefan, when I said "we" in my previous email, I was referring to VK amateurs. That makes "you" the European amateurs. :-) I don't have any suggestions. I will give it a bit of thought, and consul
Hi Markus, Well, the waveforms snapshots were taken right after the prototype was fired up for the first time on the bench. I have updated the drain waveform with what it looks like now, in fact it i
Hello group, My transmit converter is now finished and tested - it survived two sessions of 50% duty cycle WSPR transmissions on 475 kHz and the results are great. I thought others may find this usef
Hi Stefan, A photo of the coil can be seen here: http://people.physics.anu.edu.au/~dxt103/500/ The operating position is inside a little metal garden shed. I have a wooden bench and it sits on that.
Hi Eike, you are right, the drain voltage waveform is not perfect! I have since corrected the duty cycle on the gate to be exactly 50%. I have also added two 200 V zener diodes from the drain to the
Hi group, I was browsing the WSPR database for MF and noticed that I am the only one declaring a 50 W power. My TX power output is 50 W, however the radiate power is just a tiny fraction of 1 W. What
Hello group, I apologise if I am stating the obvious, but perhaps this will be of interest to someone. Old AM radio IF transformers connected back to back via a tiny capacitor make a simple but effec
Hi Andy, thanks for listening for VK stations. I plan to give it a try this weekend, if the weather is suitable. It has just rained, which is good news as my antenna's Rloss seems to be lower after a
Hi Stefan, Opperman is great, they will sell to VK and I can pay via Paypal. Thanks for making me aware of this shop and the filter. So, are you using this filter in a DC receiver front end? I want t
Hi Andy, your signal is too much. HI. Your QRG here is 136.136.171.9 For a moment, I thought that this is an IP address, and got a bit confused thinking that you are talking about some new digital mo
Hi Stefan, What I was thinking is the induced polarization phenomenon in geophysical ground measurements. It has to do with mobilization of ions near the electrodes in the ground due to the constant
Hi Steffi, I would ask the company that sells them for a demonstration and I would bring my pocket AM radio with me. These radios are pretty good at detecting this type of QRM. THese days I always do
Hi Luis, Isn't it ironic, using 10 GHz to have a chat about the kHz bands :-) Sadly, as you said, Australia isn't in the footprint. Hope one of the geostationary sats in our view will have a amateur
