Dipole switching boards

A project log for Yet Another Doppler Direction Finder w/ Teensy DSP

An update on WA2EBY's May/June 1999 QST Homebrew DDF/Radio Direction Finder

martinMartin 08/02/2019 at 23:220 Comments

I slapped together a design for a dipole PCB.  (.pdf above)  It uses a through-hole mount BNC connector on both sides.  Switching wise it works.  Antenna wise not so much.  Experimenting with a set of UHF and VHF antennas all produced VSWRs of 6 - 12 dB in parts of the UHF and VHF bands.  I tried experimenting with the resistance between the two elements which didn't make much difference.  Increasing the resistance does limit current in the switching diodes which could add signal loss.  I replaced the resistor with a diode and it works the same.

The first board was done in haste and had omitted a copper pour.  I have not laid out the board with RF design rules as I am assuming that everything is electrically small to working frequency.