I have made a mains choke for my HF station, following Ian GM3SEK's design, which involves twisting the three mains wires together and passing as many turns as possible through a Fair-Rite 0431177081 snap-on ferrite core. I wanted to measure the choke's impedance to get an idea of its performance, so I've used my Hermes-Lite 2.0 beta2 in VNA mode.
Lately, I have been trying to make an amplitude and phase calibration of my Hermes-Lite 2 beta2 in order to use Linrad's smart noise blanker. This is quite a task because Linrad doesn't support the Hermes-Lite 2 directly. Today I've finally managed to do it. Here I describe all my setup and calibration results.
This weekend I have recorded the full EAPSK63 Spanish PSK63 contest in the 40m band with the goal of playing back the recording later and reporting the stations showing excessively high IMD levels. In PSK contests, it is usual to see terribly distorted signals, which are the result of reckless operating techniques and stations which are setup inadequately. Contest rules don't help much, as they are usually too weak to prevent distorted signals from interfering other participants. Amateurs should take care and strive to produce a signal as clean as possible. For instance, in the US, Part 97 101 a) states that "each amateur station must be operated in accordance with good engineering and good amateur practice". Here I describe the signal processing done in this study and list a "hall of shame" of the worst stations I have spotted in my recording. I will notify by email the contest manager and all the stations in this list with the hope that the situation improves in the future.