Saturday, August 24, 2013

What do you get...

...when you combine a dog bumper launcher...

...with a 22 caliber blank cartridge loaded in the handle of this rather innocuous looking device?

Well...  Tie a bit of kite string around the bumper (the white bit on the end), make some big loops on the ground with the line, insert ear plugs, stand behind and well clear of the line, pull back the spring loaded plunger on the bottom and it's bye-bye-bumper...

I used it today to launch over my house (which has a 45 degree (12/12 pitch) metal roof) a belaying line so I could get up there and clean some moss off the skylights and inspect the seals.

The bumper flew about 200' in the air before the trailing line slowed it down and dropped it in the front yard.  You will get the neighbor's attention as the sound of a gun-shot rings through the neighborhood...  I live on some acreage out of the city limits, so no boys in blue arrived on my doorstep.  Guess I will fail the GSR test at the airport security checkpoint, eh?

I am not sure I can be very accurate with this thing to carefully place antenna lifting lines, but it certainly worked a treat for my get a line over the house to anchor to the pickup truck activity.

We of course had to turn a pack of golden retrievers loose to chase an untethered bumper which was a bit of a riot on a sunny Saturday in the northwest.

Monday, August 19, 2013

Time for a new antenna

I have been getting the itch to try out a horizontal loop antenna for some time now.  At the recent Salmoncon event, Eldon - WA0UWH put up a 40 metre vertical delta loop that we fed with 450 ohm ladder line.  The results were, in a word, amazing.  The top of the delta was at about 100' with the other two sides hanging downward and joined at the centre by the feed line.  Running Eldon's FT817 at 5 watts, if we could hear it, we could work it.

Wanting to duplicate these kinds of results at home, I am keen to try out a loop, but in my location, I am only able to obtain about 50 feet of elevation.  I am also interested in top band (160 metres) so a bigger loop is in order.  This will require about 514 feet of wire which works out to about 128.5 feet on a side.

Looking at my site, I have four candidate trees for supports that will provide the ability to build a corner-fed trap trapezoid loop.  The proposed site plot looks like this:

The building is oriented the long way north/south and with this orientation of the loop, I would feed it at the lower left (southwest) corner.  Each of the legs is at least 180' long, so there would be plenty of room for a 160 metre loop.  I wish I could get it up higher, but I guess that will have to wait for trees to grow.