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I have a MacBook Pro from 2012, now running Catalina. I bought it second hand with international keyboard, 8 GB and 512 SSD. Indestructible (I tried). The display hinges are a bit loose, a known problem and easy to fix. After playing with multi-boot, EFI, Linux and bootcamp, things got messed up and I needed to recover from time machine. Not a big deal, it’s all spelled out over the internet: restart with CMD-R, select your time machine backup and wait… But wait, there are two extra variants to this, SHIFT-CMD-R and ALT-CMD-R. Reading the “Guides” and Apples own info, the differences have to doRead More →

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In: Amateur Radio
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The Icom IC-9700 frequency stability can be improved by synchronising the internal master crystal oscillator with an external GPS disciplined one using the Leo Bodnar injection board. The 9700 internal oscillator is sort of pulled to the external frequency by placing a small coil close to the crystal. On the Leo Bodnar site the setup procedure is described. This procedure creates so many misunderstanding and questions that I decided to spend some words on it. First of all, the external GPS based oscillator (GPSDO) cannot be calibrated. You can set the right output frequency and level and that’s it. Now when you switch on theRead More →

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The last months I’ve been quite active on FT4 on LEO satellites. A number of challenges come together doing FT4 on sats such as accurate doppler control and time, multiple WSJT-x applications and CAT transceiver control. The doppler control is basically identical to SSB, however the update rate and/or the maximal frequency error must be set different. MacDoppler only supports update rate, which can be set up to 10 times per second. SatPC32 also supports update rate based on frequency error. Many set this to 0, meaning highest update rate. But I think that 10 Hz should do it as well. In order to listenRead More →

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FT4 via LEO satellites is becoming more and more popular. With FT4, there is less need for yagi antennas and elevation control, given the (at least) 10 dB gain over SSB communication. Or, with Yagis and elevation, you can reduce power to below 1 W. However, FT4 requires accurate doppler control and a stable transceiver, especially given the fact that many sats have a 70cm uplink. The de-facto standard for doppler control is SatPC32. This is a windows only program, and not really intuitive to configure and use. However, when configured and up and running, it’s a very powerful and accurate program. Since programs suchRead More →