Some notes before I try to do the build.
The parts I have or know I can get: cheap earbud headphones, NooElec NESDR Mini 2 SDR tuner stick with whip antenna, Nokia 635 phone, antenna from an older NESDR Mini SDR tuner stick.
Parts I need: a short adapter cable that provides antenna in for the SDR stick as a headphone jack socket.
The SDR tuner comes with an antenna, but I want to replace it with a dipole - especially one cut to have a center point for FM broadcast on 88.3 (WCBN) and a second one for 2 meter ham radio on local repeaters (W8UM on 145.23 and N8DUY on 145.15). Some sort of adapter jack (or alligator clips) should be all I need.
I can test the antenna on my Nokia 635 which has an FM tuner connected with the headphone jack as the antenna, and the ideal situation will be to have an antenna that I can just plug either into my phone or into my SDR tuner interchangeably. Once I figure all that out, the next next step is to make these antenna inputs for other radios. One step at a time though.
I'll be working from the tutorial Making a Dipole FM Antenna on willus.com .