Capacitor in place of crystal detector? - UK Vintage Radio Repair and Restoration Discussion Forum

matthewhouse · 18th May 2014, 5:56 pm

Having just tidied up a home made crystal radio built in 1924, I was playing around with it today and have hooked a speaker and a little amplifier to overcome the background noise during the day. Aerial wire is about 5 metres long, earth connected to nearest socket.

I found that a 0.01uF capacitor works far better in place of the fitted cats whisker or a crystal diode. I can tune in 5 stations at the moment, though it's not all that selective. I can easily get Radio Devon, Talk Sport, Radio Wales, Absolute and something I haven't identified yet, possibly 5 Live.

How does this work?

Matty

Edit: post 666

m0cemdave · 18th May 2014, 7:19 pm

Judging by the message number, it must be magic, but not the kind you really want to mess with...

The most likely explanation is a poor contact somewhere in the wiring or in one of the vintage components, acting as a "rusty bolt" or rectifying junction.

GMB · 18th May 2014, 7:31 pm

I suggest that your amplifier is acting as the detector.

matthewhouse · 18th May 2014, 8:46 pm

That seems to be the answer!

Herald1360 · 18th May 2014, 10:57 pm

Quote:

Originally Posted by matthewhouse

Edit: post 666

Not any longer

Your last reply killed the beast.

18th May 2014, 5:56 pm	#1
matthewhouse Octode Join Date: Jul 2006 Location: Willand, Devon, UK. Posts: 1,023	Capacitor in place of crystal detector? Having just tidied up a home made crystal radio built in 1924, I was playing around with it today and have hooked a speaker and a little amplifier to overcome the background noise during the day. Aerial wire is about 5 metres long, earth connected to nearest socket. I found that a 0.01uF capacitor works far better in place of the fitted cats whisker or a crystal diode. I can tune in 5 stations at the moment, though it's not all that selective. I can easily get Radio Devon, Talk Sport, Radio Wales, Absolute and something I haven't identified yet, possibly 5 Live. How does this work? Matty Edit: post 666

18th May 2014, 7:19 pm	#2
m0cemdave Octode Join Date: Feb 2009 Location: Bletchley, Buckinghamshire, UK. Posts: 1,223	Re: Capacitor in place of crystal detector? Judging by the message number, it must be magic, but not the kind you really want to mess with... The most likely explanation is a poor contact somewhere in the wiring or in one of the vintage components, acting as a "rusty bolt" or rectifying junction.

18th May 2014, 7:31 pm	#3
GMB Dekatron Join Date: Aug 2003 Location: near Reading (and sometimes Torquay) Posts: 3,099	Re: Capacitor in place of crystal detector? I suggest that your amplifier is acting as the detector.

18th May 2014, 8:46 pm	#4
matthewhouse Octode Join Date: Jul 2006 Location: Willand, Devon, UK. Posts: 1,023	Re: Capacitor in place of crystal detector? That seems to be the answer!