Coils and transformers

A small suggestion, has anyone tried to wind IF transformers on miniature ferrite rings? The only thing I can see against them is that it is not possible to tune them, but some form of tuning capacitor would solve this. Ferrite rings are inherently free from radiation and external coupling.

I recently bought a cartload of 10mm Dia. rings that I have used for many projects, mainly mixers, but I have stacked them up to make QRP HF output transformers for other projects. I have a lovely 5W PA (3MHz to 30MHz) that I use for testing antennas with a VSWR meter and a signal generator (running ít at lowest power).

But think about the ferrite rings, if mounted horizontally and with a trimmer on top, then they will take very little more space than a conventional TOKO IF transformer: only the thickness of the wire used to wind them.

Just a thought gents ;-)

BR Harry - SM0VPO

yes, their TOKO "clones" seem to be pretty ok, but the coilcraft stuff isn't bad, either

Andrew wrote:another source for coil "cans" and other stuff may be

http://www.spectrumcomms.co.uk/Components.htm

Hi,
this is a good shop. They seem to have rare components, like TOKO coil replacements, ferrite binocular cores or mica capacitors.

VBR from Ivan

another source for coil "cans" and other stuff may be

http://www.spectrumcomms.co.uk/Components.htm

made in USA by CoilCraft

https://www.coilcraft.com/en-us/products/rf/

https://www.coilcraft.com/en-us/products/rf/tunable-rf-inductors/

https://www.coilcraft.com/en-us/products/transformers/wideband-rf-transformers/th/wb_th/

the transformers are very small and fit well on pcb, the transformers can even be used as RX baluns, for example this one

https://www.coilcraft.com/en-us/products/transformers/wideband-rf-transformers/th/wb_th/wb9-1l/

is used in the small nooelec 9:1 balun v2

https://www.nooelec.com/store/balun-one-nine-v2-barebones.html