I upgraded my radio shack somewhat for christmas with an Icom IC-7100. Now I have access to much higher transmission power as well as an SWR meter which it has built in. With the canvas open at 145Mhz I got a VSWR of around 1.1 and with the canvas closed it increased to 1.5. This makes an interesting experiment for a future project, the change is expected but it would be interesting to see where the center frequency moves as the angle of the grounding plane cone changes. 

We've had a fairly incredible storm season this year and the umtenna handled them relatively well. Still after a few weeks of sitting out in torrential rain, one small tornado, and several hail storms only a small corner of the covering has started to tear, the top whip was heavily corroded and several of the ground plane wires had broken from corrosion and stress. 

My biggest concern by far though was my safety when a violent lightning storm can surprise you on a sunny day. Disconnecting the antenna feed is easy enough but I really don't want the canvas to be opened up and grabbing a metal pole - even an un-grounded one - is just asking for trouble. So I had an idea to try and automate opening and closing the canvas. More on that later.

Modifications ahoy! The ground radials now terminate onto a copper ring which is fed from two ends. This should provide a more reliable ground to all the radials. There was also some corrosion which I sanded off and plated with some solder paste to slow down future rust a bit. 

The next issue to tackle was the terminal for the whip. The previous build twisted the coax too much when screwing the top cover back in place. Instead of having the screw terminal in the center of the thread I drilled a new hole in it slightly to the side of that and left the center hole for the tip of the conductor to poke through freely while the cover is screwed on and can then be connected to the whip. 

And we're back in action. Re-tested and SWR is still great with this crazy thing. 

Next up I'd like to make an interchangeable HF whip for the umtenna and see if I can tune it up with the AH-4 ATU. 

Before that though I've 3D printed a worm gear winch with two spools wound in opposite directions. One line goes to the top of the antenna through two pulleys to create an upward force on the slide, the other line also terminates to the slide but providing a downward pull. That way the linear slide to open and close the canvas can be manipulated remotely by driving the winch forward or backwards. But why stop there, I'd like to calibrate that somewhat to give me digital control over the ground plane angle to plot the change resonance and possibly provide more precise tuning, perhaps even automatically.