Aerial plans

For years I have been stuck with without aerial, I have a small loop and a pull up whip both tuned, but they are very inefficient... What's worse is that my house is old, and insulated on the outside - layer of aluminium and then polystyrene blocks! So I am living in a Faraday Cage. Seems stupid. but he facts are that where I living no outside aerials are permitted, and I do not have a way to run a cable from my loft to my operating position in the downstairs hall.

But now, we are going to re-arrange the house, which will mean an upstairs bedroom will be my new location, a simple drop down from the loft above. So a loft antenna it is.

First I need a balun as it will be a sort of tuned dipole as much as I can get into the space. The target frequency is the 40m band. So here it is



A conventional design built in a small plastic box. Looks good. Two terminals and a PL259 connector.

The antenna was put up by my son in our attic. When I checked it out - using my trusty Si5351 SIGGEN and a resistor bridge feeding my trusty RF POWER METER. I found it was resonant at 8.3MHz, too high. So far I have not persuaded my son to come back and lengthen the two sides, by stretching out the spring thingy.