Frame aerial Crystal set.

[Terry]

... The picture? Why a radio, of course!

Did this picture feature a genuine speaker fabric insert, by any chance?

[Pat Pending]

... The picture? Why a radio, of course!

Did this picture feature a genuine speaker fabric insert, by any chance?

 No it didn't. Its a true crystal set that's permanently tuned to radio 5 live, and the peizo speaker (the ringer from an old landline phone) is bonded to the back of the canvas which acts as a sound board, during the hours of darkness its loud enough for comfortable listening, if the room is quiet. If you think you'd like to try using one of those peizos yourself, bear in mind that they can benefit from a series resistor or choke as they have a very high capacitance. He got the idea from a guy who posts designs for passive sets on the net. When I next visit I'll take some photos. It is a very good way to mount a frame antenna (provided the wall isn't to lossy!) What is life without whimsy!    

73. Andy

[Murphyv310]

... The picture? Why a radio, of course!

Did this picture feature a genuine speaker fabric insert, by any chance?

If you think you'd like to try using one of those peizos yourself, bear in mind that they can benefit from a series resistor or choke as they have a very high capacitance. He got the idea from a guy who posts designs for passive sets on the net.

73. Andy

Hi Andy.
Piezo sounders used in crystal sets need a "parallel" resistor, reason is the DC component from the detector has no path, it eventually will charge up the sounder and volume will decay to almost nothing.
The value actually varies it can be anything from 2meg to as low as 10k, it all depends on the sounder.

[Murphyv310]

Hi.
Today I tried adding an extra turn or two to the single turn and dispensing with the RF transformer.
Oddly performance was terrible, either too weak or poor selectivity with lower audio.
So that idea was binned!
I have fed the output of the detector using the original setup with the toroid and have an impressive log.
Radio Ulster.
Absolute
Clyde 2
Talk Sport
West Sound
Five Live
BBC Scotland
Radio 4 (Dumfries)
Spirit Radio
All perfectly clear and loud enough, even Spirit Radio!

I'm offering free demonstrations along with tea and biccys!

[AlanBeckett]

As it's only 300 Miles up the M6/M74 can I leave it until tomorrow?


Alan

[Pat Pending]

... The picture? Why a radio, of course!

Did this picture feature a genuine speaker fabric insert, by any chance?

If you think you'd like to try using one of those peizos yourself, bear in mind that they can benefit from a series resistor or choke as they have a very high capacitance. He got the idea from a guy who posts designs for passive sets on the net.

73. Andy

Hi Andy.
Piezo sounders used in crystal sets need a "parallel" resistor, reason is the DC component from the detector has no path, it eventually will charge up the sounder and volume will decay to almost nothing.
The value actually varies it can be anything from 2meg to as low as 10k, it all depends on the sounder.

Hi Trevor, I meant as well as a parallel resistor, as some of the big sounders can have 50 or so nf of capacitance that can load your tuned circuit heavily......that station log you've got there is better than you would get on many a commercial radio..respect. Andy 

[Murphyv310]

As it's only 300 Miles up the M6/M74 can I leave it until tomorrow?


Alan

Excuses Excuses

[Murphyv310]

Hi.
Seems a sentence has disappeared from the post. I fed the output of the detector to my Mullard 3-3 amp!
After Tea I will see if via the audio amp I can resolve any foreign stations.
Oh I think I'll do a small video and upload it to you-tube so anyone wanting to have a go can be inspired.

[Pat Pending]

Hi.
Seems a sentence has disappeared from the post. I fed the output of the detector to my Mullard 3-3 amp!
After Tea I will see if via the audio amp I can resolve any foreign stations.
Oh I think I'll do a small video and upload it to you-tube so anyone wanting to have a go can be inspired.

Still impressed. If the signal isn't there, you can't make it bigger.

[Murphyv310]

Hi.
Impressive results this evening. Two stations one Spanish and one French between 700khz and 575Khz were strong enough to drive phones! I wonder if that's a record for a Medium wave Crystal set?
I've done a you-tube video off the phone, I did it at just after 20:10 this evening with the output of the tuner fed directly into the Mullard 3-3. No RF amplification just my set up.
I will do a daytime one as well as Spirit Radio from Cookstown Ireland is stronger.

https://www.youtube.com/watch?v=XXI3QHyr26o