Hi, a P-channel MOSFET can be used to make a simple polarity protection circuit that has much lower voltage drop than a diode. Here's a suggestion: https://drive.google.com/file/d/1VaoIuGMQBRJWVlfiazW

Hi Alan, that's exactly what I was thinking too. I'll try a variable voltage between almost zero and max 9.5V or so. 73 SM6LKM Alan G4ZFQ wrote:

Yes, sometimes less is more. I just browsed through an old backup disk and found traces of a QRPp experiment made in 2002. My 14MHz 5mW signal reached W1TAG 5870km away. I used a 74HC00 as "power ampl

Hi The SSB receiver of QDX is about 3kHz wide so it should work well for listening to "non-digital" signals such as SSB voice. Most ops use LSB on 40 and 80 meters and while USB/LSB sideband selection

Hi Hans Congratulations to the QDX success! The PA looks like a "current switching class D" amplifier. I am curious about the drain waveform on the BS170s. It would be interesting to see how the leaka

Haha! :-) Give your XYL a big hug from us in Sweden and enjoy that dinner! Well done (to say the least!). 73 de SM6LKM Hans Summers wrote:

Hi, SSTV is actually FM which can be regarded as "continuous analog FSK" :) I don't know much about today's SSTV standards (colour and such modern stuff... :) ) but the video signal of old-school SSTV

QDX will probably work well with FSQ / FSQcall too. A fun and efficient keyboard-to-keyboard mode developed by ZL2AFP and ZL1BPU. https://www.qsl.net/zl1bpu/MFSK/FSQweb.htm FSQ is supported by FLdigi

Hi Bob There is no problem with widening the filter built around IC8/IC9 (on QCX mini schematic) but the precision of the 90 degree I/Q phase shifter (IC6/IC7) is too narrow to give a good opposite si

That was really sad news. May he rest in peace. Johan SM6LKM Den 2021-08-23 kl. 22:57, skrev radiostationx via groups.io:

Some of my friends, including my daughter, were successful in learning CW with G4FON's trainer. See https://www.g4fon.net/ 73 SM6LKM

Simply invert the signal: 73 SM6LKM AE5X wrote:

Hi, David GM8ARV wrote a nice little program that takes NMEA input from a GPS receiver and plots GPS satellite orbits. The program is quite old but it runs just fine on win10. Available here: https://

It is perfectly feasible to design a yagi for 1575MHz but it would not be a good idea since a GPS receiver works by correlating signals from many different satellites that are moving across the sky. T

The program SDR# can be used as well. https://airspy.com/download/ Select source = "Baseband from Soundcard". Use a virtual audio cable, for example VB-Cable or VB-Audio Hi-Fi Cable, to feed the demod

Hi, the video is nice but don't risk the health of your amplifier by running it with open load with high power/drive. Another approach to measuring output impedance is to use two different loads selec

Hello, I don't want to spoil the fun but I cannot resist commenting on your video #3, You are not measuring the output impedance of the amplifier. There is a steady 0dBm signal from the amplifier to t

Dominique, C41 doesn't have to be a SMD component. If you have a junk box, look for a good quality through-hole capacitor that is small enough to fit the space. I am thinking about small ceramic capac

Or if you like the Italian bread, which I occasionally bake myself, 0xF0CACC1A :) I will stop contributing to this thread now since it is impairing the signal-to-noise ratio of this mail reflector. 73

0xABADBABE! Den 2021-06-24 kl. 00:06, skrev jerry@...: