Ed Fong Antenna Troubleshooting

As program director for my club, I had Ed Fong do his standard presentation last year. He does these by request for clubs across the country and then offers a discounted group buy to the club afterward. I've built one clone of an Ed Fong DBJ and currently use it as well as two purchased antennas at my house for a base station, VHF Winlink and APRS.

Below I’ve included my personal notes on installing Ed Fong antennas that I’ve gleaned either from Ed himself or my experience with them over the past year.

The bottom approx. six inches in the pipe is just coax and not active antenna. This is for clamp mounting to a mast.
Gluing/cementing the top cap is optional. If you are suspending the antenna from the top it is highly recommended. Gluing the bottom cap (with the coax connection) WILL void your warranty. These still seal quite well with compression.

Paint of some kind is strongly encouraged. PVC degrades under UV light. Ed recommends regular rustoleum (avoid metallic colors, hammered textures, etc.) I’ve had success with tan for blending with trees and grey for blending with the sky. Another option I’ve experimented with to much success is vinyl dye from auto parts stores.

I recently experienced a failure of one of my antennas that had been up for about a year. It was suspended from the top and I believe the weight of the coax (heavy KMR400) and movement in the wind caused the nut to loosen while also expanding the hole. Eventually this movement caused a failure at the solder joint in the center conductor within the antenna. 

External before with hole expansion

Lost connection. As I recall this has one strand remaining before my movement disconnected it.

New washer after repair with fresh marring from pliers.

New solder connection with more tension toward ground than center.

This was a very simple repair but to prevent repeat failure I used electrical tape running vertically followed by the procedure in the last paragraph and captions. If you’re mounting to a mast you likely won’t have a risk of this but you could include a service loop in your coax to remove any weight on that connection.

Once coax is connected, I use a long section of coax wrap or Keeney miracle wrap starting from the coax below the connector and moving up followed by electrical tape covering that completely.

Lastly, if you are doing any measurements on these antennas you need either a balun or a long length of coax to decouple. This was a problem for one of our club members and that was the advice Ed gave him directly.