The RM30 was tested a bit this week end before the shack update, and the results look encouraging and disappointing.
The sensitivity of the RM30 looks really good, noise increases more than 30dB when a piece ow wire (in the shack) is connected, indicating sufficient gain for a grabber.
The frequency response shows the unmodified RM30 to have a slightly too low peak frequency, about 1kHz, so next test will be a (variable) capacitor in series with the input crystal, the main problem is mounting it on the PCB.
The frequency stability, however is not nearly as good as I would want. I may have to get some of the clip-on heaters that DB6NT has for sale, but initially the RM30 will be boxed and thermally insulated.
47pF in series with the input filter crystal brings the peak (rather broad) up to 10140.5 , this is quite acceptable since the bandwidth of the filter is about 1 kHz in the RM-30 setup.
Versterker Peiker Bosch microfoon - Ik kreeg een aantal Condor Peiker type microfoons. Die heb ik weer een beetje opgeknapt. De Krulsnoeren zijn vergaan en de voorversterker ontbrak. Het doel i...
1 day ago