Hello Tony, You might consider using less power. My QCX+ 40 runs on 8V and delivers 1 W. It has been running flawlessly for month's and no problems encountered. Daily, well almost daily, worldwide rep

Hello Markus, No problem: https://www.ti.com/design-resources/design-tools-simulation/filter-designer.html You need to register to be able to use it. Alignement of a 10 Hz filter is a bit challenging

Hello Lou, I believe that is your name, if not my apologies. No, I did not run a signal to noise competition. In this regard, I tested my QCX+ for 40 meter and I can hear a true -137 dBm signal. That

Hello all, - Yes, I realise that, but old style CW ops we are used to wide band RX and doing ALL the filtering in our ears/brain This is an interesting discussion. The human brain can simulate a bandf

Yuri, Forget my post as I found the answer in one of your folow up emails. 73, Roelof, pa0rdt From: "Roelof Bakker" <roelof@...> To: QRPLabs@groups.io Date sent: Fri, 25 Jun 2021 12:03:08 +02

Hello Yuri, - But I still have VFO clicks with level more than noise floor on 40m. Are you referring to the receiver noise floor or the noise floor with an antenna connected? 73, Roelof, pa0rdt

Hello Jerry, - "Why does my interest in Amateur Radio always peak at the bottom of the sunspot cycle?" Because it is too easy at the peak of the sunpsot cycle! 73, Roelof, pa0rdt

#20m

Hello Michael, Here you will find a lot of information on both P and N channel Mosfet reverse voltage protection: http://electronicsbeliever.com/how-to-use-mosfet-as-reverse-battery-protection/ 73, Ro

Hello Juliano, The problem with AGC is, if not implemented correct you end up with a system that regulates the noise, not the signal. Most legacy transceivers have excessive gain and much can already

Hello Cristi, For a different application, I am using an even simpler circuit as reverse voltage protector. The P-channel Mosfet is a Si9435 with an absolute rating of V-source-gate of +/- 20V, which

Curt, - I would probably buy a Hakko today, mine is from xytronic If you want something special, yet not too expensive, the Xytronic LF-3000 is to be considered. It uses RF heating of the tip at a fre

Hello Christi, 30 years ago, I have done some QRP contesting using a rather complicated transceiver for 80 and 40 meter of my own design. It was a double conversion superhet with an x-tal filter at 14

Hello Jerry, I have build home made attenuators using 0.6 W leaded metal film resistors. E.g. 10 and 12 dB attenuators are flat +\- 0.1 dB up to 150 MHz and from 150 - 300 MHz +\- 0.3 dB. They are exc

Hello, Passive components have been improved considerable and the cost has gone down. I suggest that you use 0.5 W metal film resistors with 1% tolerance as the difference in cost is negigible. 73, Ro

Hello Cristi, Thank you for sharing your WPX results, which I find truly amazing. It looks like the QCX+ can be classified as a 'CONTEST GRADE QRP TRANSCEIVER'! Your antenna must be working very well

Hello Glen, I have followed the same approach and used 12 or 15 mm long PCB stand offs with a diamter of 6 mm. The stand offs are available in plastic and metal. I found that the metal ones work best.

Chris, Mentioning that your audio faded out rang a bell. I had a similar issue with my QCX+ for 80 m. To take a long story short, the fault appeared to be C22, which suffered from a minor leakage. Ove

#qcxp40 #troubleshooting #fst3253

Hello Julian, The problem is whether one's brain prefers visual or auditive input. It is no surprise that many musicians are proficient Morse operators and visa versa. My brain prefers visual input an

Hello Cristi, Ken, My curiosity got the better of me and as I have collected some elderly test equipment, I checked my QRPLabs 40 m QCX+ for sensitivity. Signal generator: Marconi TF-1019, output -127

Hello Syd, My curiosity got the better of me and as I have an un-boxed vfo/signal generator at hand, I looked at it with a 70 MHz scope, which has been (free) software upgraded to a bandwidth of > 300