What materials are good for impedance transformers for VHF? Say 2-5% bandwidth and relatively low power.(matching receiver and transmitter stages so uW to mW) if using in an output filter for <30W would you suggest a different material? Trevor R.H. Clarke, K8TRC

On Monday, July 6, 2020, 2:25:39 PM CDT, Trevor Clarke via mvus-list <mvus-list@lists.febo.com> wrote:  

For low power the cores out of TV 75-300 Ohm transformers work well. Don't know at what power level the core will saturate, but pretty sure it's less than 30 watts. Kent WA5VJB On Monday, July 6, 2020, 2:25:39 PM CDT, Trevor Clarke via mvus-list <mvus-list@lists.febo.com> wrote: What materials are good for impedance transformers for VHF? Say 2-5% bandwidth and relatively low power.(matching receiver and transmitter stages so uW to mW) if using in an output filter for <30W would you suggest a different material? Trevor R.H. Clarke, K8TRC _______________________________________________ mvus-list mailing list mvus-list@lists.febo.com http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com

What impedance ratio are you needing? A toroid of ferrite could work if you need some integer ratio, but if it is more of a matching exercise, maybe a stripline would work better. The ferrite is going to be a bit lossy. Not sure I understand it the <30W part is the same question or a separate one. Tom Holmes, N8ZM -----Original Message----- From: mvus-list <mvus-list-bounces@lists.febo.com> On Behalf Of Trevor Clarke via mvus-list Sent: Monday, July 06, 2020 3:25 PM To: Midwest VHF/UHF Society Mailing List <mvus-list@lists.febo.com> Cc: Trevor Clarke <retrev@csh.rit.edu> Subject: [mvus-list] Looking for transformer core suggestions What materials are good for impedance transformers for VHF? Say 2-5% bandwidth and relatively low power.(matching receiver and transmitter stages so uW to mW) if using in an output filter for <30W would you suggest a different material? Trevor R.H. Clarke, K8TRC _______________________________________________ mvus-list mailing list mvus-list@lists.febo.com http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com

30W is a separate but related question related to material for a transmit lpf/bpf I was hoping to avoid a custom pcb and use microwave proto boards and short traces. Frequencies are 50MHz and about 200MHz. Impedances are 50ish ohm for interconnects and I/o impedance vary with device, up to 1.5k or so Trevor R.H. Clarke, K8TRC On Mon, Jul 6, 2020, 4:16 PM Tom Holmes via mvus-list < mvus-list@lists.febo.com> wrote: > What impedance ratio are you needing? > > A toroid of ferrite could work if you need some integer ratio, but if it is > more of a matching exercise, maybe a stripline would work better. The > ferrite is going to be a bit lossy. > > Not sure I understand it the <30W part is the same question or a separate > one. > > Tom Holmes, N8ZM > > -----Original Message----- > From: mvus-list <mvus-list-bounces@lists.febo.com> On Behalf Of Trevor > Clarke via mvus-list > Sent: Monday, July 06, 2020 3:25 PM > To: Midwest VHF/UHF Society Mailing List <mvus-list@lists.febo.com> > Cc: Trevor Clarke <retrev@csh.rit.edu> > Subject: [mvus-list] Looking for transformer core suggestions > > What materials are good for impedance transformers for VHF? Say 2-5% > bandwidth and relatively low power.(matching receiver and transmitter > stages so uW to mW) if using in an output filter for <30W would you suggest > a different material? > > Trevor R.H. Clarke, K8TRC > _______________________________________________ > mvus-list mailing list > mvus-list@lists.febo.com > http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com > > > > _______________________________________________ > mvus-list mailing list > mvus-list@lists.febo.com > http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com >