[Lowfer] Beacon DIR on the air...

[Jim]

Well, it's been a busy afternoon. I was traveling on business last week and 
have been dealing with two flat tires for my wife and various other chores in 
addition to the beacon. But I have just finished up a productive hour and a 
half with the beacon and my mine-whip active antenna.

I had been powering the beacon using a Lambda "brick" supply that gave me 12 
volts out. I swapped that for a variable supply that has voltage and current 
meters. To make a long story short, I noticed a significant disparity between 
the current meter on the supply and what I was measuring at the radio. I 
thought I'd put in a 1 ohm resistor to measure the voltage drop across and 
calculate current. Instead it was a 0.1 ohm resistor. So my current 
measurements were off by a factor of ten.

In the process of figuring this out, I shorted the protection diode and 
measurement resistor out and I'm feeding the power straight in. I used a 
couple of sections of old extension cord I had (the orange outdoor stuff that 
I snagged from a dumpster behind a store that had the ends cut off of them) 
for power and I'm using Cat 3 cable to carry the square wave out to the 
final.

I also made a few changes to how I have the antenna connected. I built a 
tapped matching coil on a five gallong bucket. It's wound top to bottom with 
14 gauge solid wire and tapped about every ten turns. I used the rest of the 
wire that was on the 500's spool as a loading coil and it's located on top of 
the 5 gallon bucket with it's own smaller bucket protecting it. That runs up 
the center leg of the T. It's located beside a wire fence that runs around 
the portion of the yard where we keep the dogs (maybe a quarter of an acre or 
a bit more). I've connected to that fence for my ground.

At this point it's running 13.7 volts at 70 mA. I'm measuring from the power 
supply instead of at the xmitter final now, but the line loss isn't much and 
the meters only read to .1 accuracy on voltage and .01 accuracy on current so 
the margin of error puts me right around the one watt mark.

I have "optimized" using just a field strength meter. I want to build 
something to let me actually measure antenna impedance, an RF current 
measuring device and, at some point, a bit better matching arrangement. But 
this was mainly about getting something on the air.

I had moved my active mini-whip antenna last weekend to make room for the Part 
15 xmitter antenna. After moving it, I couldn't hear the local LF power house 
GPQ-278. So I was working on that and finally figured out that GPQ is off the 
air. So where I thought I had a problem and spent about thirty minutes taking 
measurements and such, turned out to be no issue. The active antenna runs 
through a LPF, and I didn't figure all this out until I removed the LPF to 
test it and found that the active antenna was doing a fine job of bringing in 
WWV.

Fixed a hole where my daughter's chihuhua had dug under the fence and a flat 
tire on my wife's truck. So it's been a productive day... :-)

73 de
Jim W4JBM

Receiver - Ten Tec RX320D
Antenna - Butternut Vertical (SW) and mini-whip (LF)
Location - Bowdon Junction, GA  USA (33.6581,-85.1249 EM73)

http://www.hamuniverse.com/w4jbm/

"With a soldering iron in one hand, a schematic in the other, and a puzzled 
look on his face..."

Working the world from the New Dog Iron Ranch!