Bun's Lab – Telegram
Bun's Lab
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Electronics projects, vintæg computing, programming and repairs. A minimalist blog of sorts.
@BunsGarden @BunsNook
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The IFs were both off frequency. I tried to adjust them, only to find out, they cannot be adjusted. Where I thought a core slug was lurking was in fact nothing but a concrete like ferrite material. In my attempts to turn what I thought was wax covered slugs, I ended up killing one of the IF coils. Fixed it again.
And then I experimented with tuning them with additional trim caps.
I ended up moving the IF by 5 kHz to 460 kHz, as this gave me the largest peak within the range afforded by the trim caps
These IF cans were meant to be a set and forget kind of deal, with a frequency set during my manufacturing. Somehow the frequency has drifted, by quite a lot. One of them was at 425 kHz.
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Receiving some Bangladeshi(?) station. Around 1420 - 1435 kHz. (LO is at 1899 but I forgot my IF frequency, I've changed it again)
I'm located in Europe.
Ran Shazam on one of the songs and it gave me a Bangladeshi singer.

Edit: measured the IF to (469.6 +- 0.3) kHz, by injecting a signal into the mixer and adjusting for lowest beat frequency
The antenna I used: a small ferrite antenna just dangling about
A knob came loose and the modulation switch is having contact issues. So let's have a quick look inside this signal generator 👀
I love how simple it is.
Trim caps! Got them for a good deal. About 14 cents a piece.
Let's have a look at my nas! It's an HP N54L.

There is just one slight problem though. I lost the keys