George's Leak Troughline Antenna
Posted by: Simon-in-Suffolk on 23 September 2015
Hi George, I thought it better off to start a new thread for the Leak Troughline antenna .. checking the circuit diagram of the Leak (see below), the antennas inputs go into the balanced (300 ohm) and unbalanced (75 ohm) taps of a transformer. Now using the unbalanced taps you can connect the 75 ohm coax using the shield connected to the ground as you have done but then the other end of the coax you have to convert the unbalanced lead to a balanced feed for the balanced antenna (full wave loop, dipole, Yagi etc) using a Bal-Un - which again is what you have done - but you are introducing losses and you might as well go balanced end to end using 300 ohm ladder line feed as you are using a balanced antenna
http://www.radioworld.co.uk/la...bCjMgCFRSNGwodicAIjA
(you could use regular TV/FM 300 ohm lead, or at a pinch a very short run of twin bellwire - but this will be lossy - but it wont be as ideal as the 300 ohm ladder line)
This will be optimised to connect to your Leak antenna 300 ohm terminals.
The full wave loop antenna has an impedance of 100 ohms, but as a receive antenna this mismatch will be fairly inconsequential
Here is the Leak Troughline circuit diagram that confirms the antenna input is designed for balanced feeds at 300 ohm as well as unbalanced at 75 ohm
Your circumference appears ideal for your fullwave antenna already at 3.24m.
And remember using the ladder - line no lossy balun is required at the antenna which is why it should be advantageous over the coax for that type of antenna - but as always experiment!!!! - you might have struck lucky and be optimum now - but you wont know until you try 
Good luck
Simon
Back in time.....
You just need a pipe...
Joff
Dear Joff,
Well my arrangement is more monastic, but the general severity of the look does not spoil the music!
I wish I had had my slippers on, and then my long redundant pipe would have fitted right in!
Beats having a wacking great video screen between the speakers though!
ATB from George