Hi Tim
Try an air cored transformer (no unobtainium) about 100mm diameter about 60 turns of 1mm diameter wire. Using a shorting tap from the antenna end down the coil. Use about 1 to 2 turn loop at the earthy end for your 50ohm TX. The earthy end of the coil should be connected to a good earth system.
This should give a coil about 300yH with a Q of about 400. You don't need a capacitor just tap carefully down the coil. Remember you will have about 2 kV floating about and 1.5 amps in the up lead with a watt and a bit radiated for a 100 watt TX.
My antenna is up 13m and I use the above arrangement.
From: tim hague <[email protected]>
Subject: LF: Antenna Matching
To: [email protected]
Date: Sunday, 28 March, 2010, 11:10
I'm just about to apply for my 500kHz NoV, I've got around 100W of Tx power available and I'm looking for some information on antenna matching, my Tx antenna is just going to be a 132ft Marconi T with a 50ft vertical section, can I get away with just a series tuned matching cct or are the voltages across my matching C going to be very high, I have a wide spaced C approx 200 to 700pF.
Thanks Tim M0AFJ
