Signal Report

 After a fair amount of time using the 2643251002-based common mode choke (CMC) (current balun?), I got curious about how much attenuation it presents to common mode currents. I cobbled together a test jig, and connected it to my nanoVNA.   The 2643251002-based common mode choke (CMC), with 3D printed spider, hot melt adhesive, and self-amalgamating tape.    

 Owen Duffy simulated a Common Mode Choke (CMC) using RG316 coax and  2643251002 toroid ferrite core . See his post here . I found the double-shielded RG316 coax I was using had a life of its own with regards to routing. My understanding is that windings close together boast capacitance, which can negatively affect the choking performance, especially at the high frequency end of the HF spectrum. I designed and 3D printed a part which solves this.

 The MC-750 is a ground-plane antenna, designed for easy setup and takedown - perfect for field ops like POTA. The MC-750 is well made. Others can review this antenna better than myself. Instead of a review, enjoy these photos of the MC-750 antenna.

 As illustrated in this photo from the manual, the Fuchs B25 transceiver was designed to be operated manpack portable with a whip antenna. To couple this whip antenna to the transceiver, an Antenna Tuning Unit (ATU) is employed. ATUs normally enable the use of a wider range of antennas, however the B25's ATU was designed for a specific purpose and is not so adaptable.

 The End Fed Half Wave (EFHW) is a convenient antenna. The core component is a wide band impedance matching transformer. As with all antenna systems, efficiency is a key metric. Special selection of the transformer core and winding style can allow for an acceptably efficient EFHW antenna.

Banana connectors are quite ubiquitous in the electronics world, and rightly so: they are versatile, inexpensive, and easy to terminate. However early on into my electronics engineering journey I discovered there are some bad  apples  bananas to lookout for.