The Antenna Farm Is Growing

Posted on Sunday, March 10th, 2013 at 7:20 pm in

Antennas From Chimney

Antennas From Chimney

Although the picture is very skew and not a good rendition of the antenna, I built myself a “test” version of the Balanced Termination Folded Dipole (BTFD) as shown on his website by Buck Rogers Sr K4ABT of BUXCOMM.

Now before we carry on I need to acknowledge my friend and colleague Bruce Rodrigues who used to say: “There is nothing more permanent than a temporary fix”. This antenna might go in the same direction, I like what I hear.

Firstly I wanted to find out for myself if the folded dipole, terminated in the middle with a 450 ohm resistor, would be more quiet and still receive low level signals. So I made a rough hand sketch of two side loops with 21 meters of wire each side. I didn’t have proper antenna wire so I used electric fence wire – lots of that around. It is a multi-strand wire, silvery-looking, and it is very stiff so it must be steel or something. I bought a 10mm dowel, cut it into 220mm pieces and drilled 2mm holes near the ends for he wire to pass through. I purchased a random 25 watt 470 ohm resistor (I have no idea if it has inductance or what) and with electric fence crimp collars wired up the works in less than an hour. I’ll post some photos later. The balun is a problem as I don’t have a 9:1 balun available, so I used my standard 4:1 balun and I’m expecting some degradation because of that. I strung it from the highest point on the chimney pole to a roof eave in a slightly E-W direction.

The photo shows the middle area of the antenna with the resistor on top and the balun below.btfd

Comparing it to my MFJ Junior G5RV on-air (below the BTFD in the picture) it was giving very similar signal reports, and it was about 2 S-points quieter. This is enough to do some more scientific measurements and make some refinements, like replacing the balun. Initial impressions were very favourable and I’ll keep you posted.