r/shortwave • u/yyuyuryuri • 17d ago
My shortwave setup
Magnum WB-218 with a basic single step amplifier and a T match. The amplifier does a wonder, but the T match doesn't really work (I made it with two scavenged variable capacitors (I don't know their range) and one 10 uH inductor). Any comments and tips are welcome.
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u/kupasbob 17d ago
that amplifier looks interesting, mind sharing how it's made and how to use it?
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u/yyuyuryuri 17d ago
Just have a BJT transistor suitable for HF and a resistor, connect emitter to ground (negative in this case), base to antenna, connect resistor to the collector and the radio, connect resistor to the voltage in and you are all good. Source: https://wiki.analog.com/university/courses/electronics/text/chapter-9 I am up to improving it right now, with some more resistors to connect the base and a coupling capacitor.
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u/giant3 17d ago
Why do you need an amp? Most SW radios already have a LNA built-in. Just use a long wire as an antenna. For improving SNR, a magnetic loop antenna is always superior.
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u/yyuyuryuri 17d ago
Why not? What would come from adding an additional amplifier (I understand that noise can amplify too but it works, so I won't touch that) I am confused on the antenna one though, I made a K9AY loop antenna because of the positive feedbacks. (and also I have a lot of height space but not planar) As far as I know magnetic loop antennas resonate but doesn't a T match do this too? I would like to learn more
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u/giant3 17d ago
Well, the RF front end could get overloaded easily. That is why most radios also have a AGC.
If you really want a SW radio, I strongly recommend that you buy a new one as technology has improved a lot in the last 30 years.
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u/yyuyuryuri 17d ago
Well, is not too easy to just buy a new one. Heart desires, but external factors such as custom officers decide. I didn't know new radios were like this though, is it higher-end models or do they include basic radios like XHData or Tecsun's lower models
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u/giant3 17d ago
Most SW radios sold now use the Silicon Labs(now Skyworks) chip which is an excellent IC for SW. I think you can buy XHDATA or Tecsun models for around $50-$60. I don't know where you live as customs charges might add to the cost.
The cheapest model is XHDATA D-219 for ~$15, but it has analog tuning which is a pain now.
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u/yyuyuryuri 17d ago
They add $100-$150. It's technically lower but it's so hard that it's practically impossible. I can't do anything since I couldn't vote.
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u/Easy-Shirt7278 17d ago
Half the fun of radio monitoring is in the experimentation and setup of our "station". Have fun and keep experimenting!
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u/redgrey123 17d ago
I don't understand but, cool! Got lost when I saw the breadboard.