Building an effective HF antenna can be difficult when space is limited, building a beam antenna may appear impossible if you don't have enough room to house the directors and reflectors required by these beam antennas.
However, it may be possible to use your loft space to house an inverted 'V' Yagi beam antenna! Beam antennas focus radiation and sensitivity in one direction, allowing you to make contacts further away.
Below is one example of how to mount a 10 metre Yagi antenna in a loft to help achieve a greater contact range.
To fit this antenna in an attic space, I used an inverted 'v' configuration. I initially feed the dipole directly with a 1:1 balun and RG58 coax. This was okay but appeared noisy. I later changed this by feeding the dipole twin feeder via a remote balun. This was found to be quieter and made the antenna less sensitive to frequency changes.
I used TV coax to make up the dipole legs and elements. Only the outside screen is used. Why? Having a wider conductor reduces the q-factor a little which makes the antenna a little less sensitive to frequency changes (so I have been told), it also has a low resistance. I've used this method before and found the results to be good. I terminated the outer screen into a crimp and put heat-shrink over the join.
The reflector is the most important element. It is a single coax conductor, 5% longer than the total length of the dipole. It is placed at exactly the right length away from the dipole.
Elements are added in the same way, but these at 5% shorter. You can have between zero to three of these depending on your space and needs.
It is important to be careful when working in the loft. Accidents happen when we become complacent. I have put my foot through the ceiling in the past, so it can be done. Always make sure there is somebody else around in the house who can help if you get into trouble. Please don't attempt this antenna if you are not entirely sure of your safety.
If you have the space (which is likely for some), here is the 20 metre option: