Not saying that I approve use of DSB on HF bands, but there are some interesting reasons that it might be attractive: 1) DSB is easier to design and build, especially if it is a direct-conversion desi

Seems that if regulation is by bandwidth, then AM would fall under the same spectrum restrictions as DSB? CW might even be bandwidth restricted at higher speeds? Arv K7HKL _._

http://home.alphalink.com.au/~parkerp/projects/projbeach40.htm _._

If the pecking noise is that loud, it should be possible to trace it with an oscilloscope. Opening the path from RF to AF could be part of the source isolation process. 1) scope the power supply outpu

If you have a volt meter you can measure the voltage presedt across the cap pads when the circuit is powered. That should be close to what is present when the circuit is operating. Capacitor voltacge

What is the voltage that those caps will be subjected to? If less than 18 volts or so the 25 volt caps might work fine. Arv. K7hkl _-_

In the "bad-old-days" we had to contend with brown-body resistors (brown is one of the color code bands). Then it was gray resistors (gray is a color code band). Seems that most of the popular colors

Don Are Blue LEDs the reason he cannot find minimum on the QCX trimmers? Arv K7HKL _._

Hans You are correct. I did not notice the blatant off-topic nature of my response. QRP-Labs stuff belongs with QRP-Labs group and BITX stuff belongs on the BITX group. Sorry about the confusion. Arv

The early BITX20 and BITX17 were all user built without PCBs. Then parts kits and a few PCBs started appearing. Most of the early builders used "ugly-construction" technique with leaded parts. Seems t

Alan "The actual frequency is not important"...true for Hans application. I use an Arduino to count frequency and to push/pull a VFO to a user set frequency. For that the accuracy of the AVR crystal i

Chris Good! I'm not sure why the manufacturer specifies capacitors unless it is a way to set the oscillator to a very specific frequency. This might be needed if we were using the microprocessor to me

Torbjorn A single Li-ion cell could provide 3.2 to 4.0 volts (depends on charge state) for powering the GPS receiver part. Very small 1S Li-ion charger boards are available from Ebay suppliers and cou

#qcx

Chris I would try it without the caps, but build it so that the caps can be added if necessary. Arv _-_

O.1 watts = SQRT(0.1 * 50) = 2.23 volts Avg. 2.23 * 1.4 = 3.22 volts Peak. That should light almost any modern LED, since modern ones need less than 2V at 3 to 6 ma for adequate brilliance. There is a

#antenna

John, and others... Hans has provided some interesting glimpses of what the QSX might include. http://qrp-labs.com/newsmay2019.html#c2 http://qrp-labs.com/qsx From those references we should be able t

#qsx

To extend Hans answer...the wire is "magnet wire" not "magnetic wire", and it is not magnetic material. The name "magnet wire" comes from history when it was wound on ferrous cores to make electro-mag

https://groups.io/g/antennas _._

Jack When you do the write-up you might consider including some detail on the tripod. That looks interesting. I am assuming that it is made from PVC pipe? Arv _._

Several potential problems with filters that do not seem to be working correctly. 1) Inductance is wrong 2) Capacitance is wrong 3) Soldering problems 4) Impedance mismatch on input or output, or both

#qcx