As you were disconnecting the radials the ground losses were increasing until it got to enough ohms and you had a good match at 50ohms.

My 160 T matches 25 ohms 1.12:1 at 1812Khz and is fed with a 50:25 transmission line transformer. With 8x 125' elevated radials the N6LF research shows I have fairly low ground losses.


As I added radials, I tracked my swr and it steadily decreased, pretty much asymptotic to 25 ohms. Different L or T geometries will yield different resonant impedances, but most will be well less than the full 1/4 wavelength 36 ohms. With an analyzer you could measure the Z as you reconnect radials and learn a lot about your antenna SYSTEM.

TLT's are winners IMO for matching resonant antennas, wide bandwidths ,very low losses, and essentially no sensitivity to the environment.

Grant KZ1W

On 12/1/2016 12:14 PM, K1FZ-Bruce wrote:
This is normal, but without the radials your RF is mostly heating up the earth. If you make the L a little longer, then insert a variable capacitor at the feed point, you should be able to find a higher feed point with the radials connected.. With trial and error 'juggling' the extra wire length and capacitance. you can get very close to 50 ohms, and get a good signal out for DX.
73
Bruce-k1fz
http://www.qsl.net/k1fz/beverage_antenna.html



On Thu, 1 Dec 2016 19:59:57 +0000 (UTC), james soto via Topband wrote:

Hi allLast year i install an inverted L antenna for 160 with few radials different lenght.ohms was between 20 to 25 ohms and swr about 2.2 . This past weekend i was checking thethe antenna with the mfj analyser and i proceed to disconnect the radials from the groundrod and just leave the ground portion of the coax attach to the ground rod and the reading wasSWR 1.2 and 50 ohms. are this normal ?
Thanks
KP2BH / jimmy
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