EA8/LA3ZA April 2023
The best bands were 30 m (29%) and in particular 10 m (65%) with a lot of contacts across the Atlantic ocean as the picture shows. In total 62 different entities/countries were contacted.Β
QSL via Logbook of the World.
The best bands were 30 m (29%) and in particular 10 m (65%) with a lot of contacts across the Atlantic ocean as the picture shows. In total 62 different entities/countries were contacted.Β
QSL via Logbook of the World.
But first, I do actually have experience in blowing the finals. That happended under testing prior to leaving, and all it took was 9.5 Volts for my 9 V build and what I thought was a dummy load, but which might have been an open circuit load. One BS170 developed a short between drain and gate with the result that 9.5 Volts was passed directly into the outputs of the driver IC5, 74ACT08, so IC5 blew as well.
My three tips for avoiding such failures are:
I turn it down to 7 Volts for manual tuning of the antenna and up to 9-9.5 Volts in order to achieve near 5 Watts output. If I exceed 10 Volts, the power module is set to turn itself off.
The latest firmware, version 1_04, has a new "Band Configuration" screen where one may configure the list of supported bands. It is the intention that higher bands will eventually be supported.
I am not so interested in 80 m, so I wanted to see if I already now could get the receiver to work on 17 m and 15 m. With reference to the schematics, I modified the input filter's inductor, L12.Β
It is tapped at 19, 30, 36, and 41 turns for 20, 30, 40, and 80 m respectively. It resonates with input capacitors C28-C31, with 22, 30, 56, and 220 pF respectively.Β
I gave the inductor 36 turns, omitting the extra turns for 80 m, and then tapped L12 after 13 turns. I also also changed C30 to 15 pF. That give me theΒ bandpass characteristics shown below, as analyzed with the built-in analysis function of the QDX:
Here's a new sweep with firmware 1_05_002 (beta) which uses colors which are easier to read: