[Elecraft] Inverted L for 160 meters

[tony.kaz at verizon.net]

As a reference, I have an 80M 4-sq with 5 elevated radials at each feed point and use a Comtek box. The radials were 1/4 wave. The pattern was terrible. Very little F/S and F/B. I measured the current in each radial. It was all over the place. I followed N6LF's info and cut the radials to 42'. I connected all 5 radials together at each feed point then added a small coil between the 5 radials and the coax shield to retune the elements. Now the current is very close with each radial and the F/S and F/B is much, much better. Read N6LF's stuff and take a look at balancing elevated radials if you go that route.
73,
N2TK, Tony

-----Original Message-----
From: elecraft-bounces at mailman.qth.net <elecraft-bounces at mailman.qth.net> On Behalf Of David Gilbert
Sent: Wednesday, August 26, 2020 2:11 PM
To: elecraft at mailman.qth.net
Subject: Re: [Elecraft] Inverted L for 160 meters



Yes, certainly current balance would minimize ground losses.  I hadn't thought much about it before, but I guess it's kind of intuitive in that it's analogous to lower return resistance losses due to better use of parallel ground paths.

73,
Dave  AB7E



On 8/26/2020 10:42 AM, Jim Brown wrote:
> On 8/26/2020 10:07 AM, David Gilbert wrote:
>> Radiation angle for a vertical antenna is much more a function of the 
>> ground conductivity out several wavelengths than it has to do with 
>> the current balance in the radials.
>
> Right, but N6LF has shown that current balance in radials, especially 
> elevated ones, minimizes ground losses.  Yes, elevated radials can be 
> modeled in less capable versions of NEC. All of this is addressed in 
> my slides.
>
> In all cases, the model must use soil conductivity representative of 
> the QTH. This is selected from a menu. Soil conductivity affects us 
> two ways. First, losses underneath the antenna. Better 
> radial/counterpoise systems can reduce this a lot. Second, loss in the 
> far field, over which we have no control, and those losses can vary a 
> lot if soil varies a lot in different directions. For example, a 
> vertical on a beach has much less far field loss, and much more energy 
> at low angles, in the direction of the water and much more far field 
> loss and higher angle energy than in directions over land.
>
> 73, Jim K9YC

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