I spent the weekend building stuff.

RF Probe

First, I built an RF probe using a schematic from the ARRL Handbook.  It’s a pretty simple build, as all I needed was a pair of old test probes, a germanium diode, a capacitor, and a resistor.  I packaged the electronics in a small piece of CPVC pipe, which is nice and unobtrusive.

This is the RF Probe. It fits nicely in some 1/2″ CPVC pipe.

End Fed #2

After W0EA told me I used the wrong coil core material, I built one with the correct material (ferrite, not iron).  I still have the old, so I’ll do some comparisons, but barring any major issues, I’ll stick with the ferrite one.

End Fed #2.

-73-

I don’t have much to post, and with weekends being nearly as busy as weekdays, I haven’t had much time to get into anything, but I did get some time working in the shack on a Par style end fed antenna.  I started thinking about this and worked off the design on W0EA’s blog.

This is the inside of the box. I used an Altoids tin. The coil wire is small enough that I would consider this QRP only.

This is the back of the matchbox. It is difficult to tell in this picture, but the bolt is insulated from the case. At some point, I will improve this to have an insulated connector (right now, a good tug may cause the bolt to contact the case).

Soon to be trap. And for the love of all that is holy, DO NOT COUNT THE TURNS. It isn’t done, and I was adding turns when I should have been removing – this coil resonates on 10m, not 20m like I need.

  -73-

UPDATE: W0EA connected with me via twitter to tell me I’m doing it wrong.  Specifically, I should be using a ferrite core, not an iron core.  Looks like I’ll be winding a new coil this weekend.