My first satellite QSO was with my good friend OM Bindu - VU2IR.
It was around 6.00pm, one evening in the early 1990s, when Bindu and I were chewing the rag on 2m and he excused himself to work through a satellite.
I was curious when he said he would work SSB via RS-12 with a 21MHz uplink and 145MHz downlink and would I care to join?
With hardly 10 minutes to go, I hurriedly set up a Yaesu FT-757GX (just serviced and ready to be delivered) with my 40m inverted 'V' dipole antenna for the uplink. My homebrew 2m converter and ¼ λ ground plane antenna would serve for the downlink, with my RCA BC312-D receiver as the tunable IF stage (see My homebrew 2m FM rig for more details). And my first satellite contact was thus established.
Fortunately, it was just the two of us and we continued our ragchew for the duration of the pass. With OM Bindu just 5km away, it was once again proved that the long way round is the short way!
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Remembering radio pioneer J.C.Bose
Here's a comprehensive article on radio pioneer J.C.Bose.
J.C. Bose: 60 GHz in the 1890s
J.C. Bose: 60 GHz in the 1890s
Interesting read.
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Crystal Radio Circuits - Alternative Concepts
1. Parallel-tuned, series-fed configuration:
The diode-clipped parallel-resonance voltage is output to the phones.
2. Series-tuned, shunt-fed configuration:
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| Parallel-tuned, series-fed Crystal Radio circuit |
The diode-clipped parallel-resonance voltage is output to the phones.
High-impedance diodes and phones are required to match the high impedance of the parallel-resonant
circuit.
This configuration is suitable for reception of distant, weaker stations.
2. Series-tuned, shunt-fed configuration:
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| Series-tuned, shunt fed Crystal Radio circuit |
The diode-clipped series-resonance current is output to the phones.
Low-impedance diodes and phones are required to match the low impedance of the series-resonant circuit.
This configuration is suitable for reception of nearby, more powerful stations.
3. Series-tuned, shunt-fed variant:
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| Series-tuned, shunt-fed Crystal Radio variant |
This is a variant of the above series-tuned, shunt-fed configuration.
Using low-impedance diodes and phones, it delivers identical performance.
Related post: Parallel-tuned Compact Loudspeaker Crystal Radio
Related post: Parallel-tuned Compact Loudspeaker Crystal Radio
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