17-08-2017, 07:05 PM
Hi.
Thread revival!!!!
I've been playing about with the frame aerial again.
What I've discovered is the single turn winding is not required when using a toroid to do the matching. The single turn is not that efficient so using one turn tapped off the innermost part of the main winding is all you need. This is then fed to a winding to the toroid. A secondary can then be wound on the toroid just like on the original.
Overall the sensitivity and volume are higher and depending how you work out the turns ratio and load, selectivity can either be improved or traded off for greater volume.
I've a few different Ferrite rings to test to see if any further improvements can be made.
I'd like to try a piezo headphone but all I have is those rubbish crystal earpieces, results with the German phones are very good.
Thread revival!!!!
I've been playing about with the frame aerial again.
What I've discovered is the single turn winding is not required when using a toroid to do the matching. The single turn is not that efficient so using one turn tapped off the innermost part of the main winding is all you need. This is then fed to a winding to the toroid. A secondary can then be wound on the toroid just like on the original.
Overall the sensitivity and volume are higher and depending how you work out the turns ratio and load, selectivity can either be improved or traded off for greater volume.
I've a few different Ferrite rings to test to see if any further improvements can be made.
I'd like to try a piezo headphone but all I have is those rubbish crystal earpieces, results with the German phones are very good.
