Andy wrote:
Hi,

I have a 40 meter centre feed dipole cut for 40 and feed direct with 50 Ohm
coax. The house end is connected to the centre of the coax and the pole end
is connected to the braid. Seems to work best this way round.
The antenna is fixed tight to the house and the other end is tight to the
metal pole in a straight-line, diagonal across the garden, both ends are
insulated. The garden is about 64 feet give or take a couple of feet.

I cannot drop the ends down because of the house and metal pole at the end
of the garden being so close. I can only feed the antenna with coax. The
neighbours are OK with coax but not the ribbon feeder hanging down and I
don't want to upset them if I can help it.

My question. What are my options to enable me to operate 80 and 40m on this
same antenna wire?
===========================================
300 Ohms ribbon twin feeder is hardly more visible than coax feeder .
You don't have to use the 'wide' 450 Ohms ribbon type.
300 Ohms ribbon has an approx velocity factor of 0.8 ,so if you make
half the dipole + the feeder (roughly) an electrical 1/4 -3/4 -etc
wavelength at 80 meters ,you will be home and dry with an appropriate
matching unit or a choke balun in combination with a 'coax-in ,coax-out'
matching box.

Frank GM0CSZ / KN6WH