Topband: Inverted L Radials

[Grant Saviers]

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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