Here's a nice little project which should only take about a day to complete. I found it while trawling the net a few weeks back. It's for a 30 meter loop antenna, very easy to build and so far seems to work well. I've got it strung across a couple of trees, unfortunately not very high about 20 feet but it works reasonable well and is a bit of fun for a weekend project. Have a go and see how you get on.
This antenna is an easy construction project. It was made out of common number 12 stranded electrical wire. The side and top attachment points are made by removing two inches of insulation and wrapping and soldiering in short lengths of wire to create small loops. Non-electrical rope should be used for the support line and side pull out lines. The bottom insulator should be about 3 by 5 inches in size and trimming the antenna to resonance was done at the bottom.
Start with the formula of 1032/Mhz to determine the total length. I ended up pruning about a foot off of each side to achieve resonance at 10.125Mhz. I used 72 ohm RG59 for the matching section. Make sure you take into account the velocity factor of the coax when cutting it to length. One method is to place a 100 ohm resistor at the end and use an antenna analyser designed for 50 ohms to measure for zero reactance (and SWR) while trimming the section to the correct length.
At 10.125Mhz, the SWR is 1.1/2 : 1, R is good at 50 ohms (When I got these results, I decided not to build a balun).
Within a couple of hours of putting up the antenna I had made five DX QSO's. It has performed well ever since. The antenna is not overly directional probably due to the wire sections all being 45 degrees with respect to ground.