My other hobby is building "high-tech" crystal radios. I needed a really
sensitive set of headphones
but didn't have the cash to lay out for a pair, so in true ham tradition, I
made a pair to suit my needs.
I bought a high-qualty pair of ear defenders, which any safety or industrial
equipment retailer should
have on hand, and put two earpiece elements from old rotary dial telephone sets
into each side with
some creative cutting of the foam inserts. The elements I used came from Bell
500 series phones
and wired in series have an impedance of around 600 ohms. They work really
well, allowing me
to pull the weak ones out of the noise of the AM broadcast band.
73, J.B., VE3EAR
LowFER Beacon "EAR"
188.830 kHz. QRSS30
EN93dr
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