Hello Yannig, For an antenna you might look into the doublet, fed with open feeders / ladder line. I have used one measuring 2 x 7 meter, which worked very well on all bands from 40 to 10 meter. This

Hello Yannig, Presumably I also need a tuner ? Yes, that is the only downside, but considering the same antenna can be used on 40, 30, 20, 17, 15, 12 and 10 meter it is certainly worth the extra effor

Hello Yannig, This is a good read to start with: https://wb3gck.com/2020/03/10/the-doublet-revisiting-a-classic-antenna/ The Z-Match tuner is also mentioned and a hyper link is available. You might lo

Hello Yannig, You can roll your own Z-Match, but you can also look into this European source: https://www.qrp-shop.biz/epages/qrp-shop.sf/de_DE/?ObjectPath=/Shops/qrp-shop/Products/ZM4 73, Roelof, pa0

Hello Yannig, You can use unsplit speaker wire as a balanced feedline on 40m. You don't even need a balun, but a 1:1 balun will help to balance the antenna and reduce noise pick-up. The beauty of this

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

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 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

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 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.

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, 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 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 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

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 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

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 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 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 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