[TowerTalk] Vertical question

[Grant Saviers]

N6LF has several plots of the change in gain for elevated radials 
shorter than 1/4wl.  For elevated, about 15% shorter then 1/4wl is the 
peak IIRC.  WA3FET did calculations of best # & length for a given total 
length of radial wire on the ground. YMMV.

Grant KZ1W

On 3/15/2021 12:52, N4ZR wrote:
> This is the second allusion to 1/8 wave elevated radials that I've read, 
> but I've been unable to find anything further, in the usual sources. Any 
> leads?  I have an inverted L, but really don't have room for 1/4 wave 
> elevated radials and am told that my 8 x 70 foot radials on the ground 
> really aren't worth much.
> 
> 73, Pete N4ZR
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> On 3/15/2021 3:00 PM, Ignacy Misztal wrote:
>> My feeling is that modeling with verticals is less than perfect or 
>> perhaps
>> the interpretation of results from modeling is imperfect.
>>
>> In 160m contests we hear signals that are poor, OK and spectacular. In
>> cases I know, those OK have 30 radials and those spectacular have 100
>> radials. While the maximum angle radiation may be affected by < 1 db,
>> perhaps low angle radiation may be affected by 10db or more.
>>
>> I had an inverted L with up 80 feet with 4 elevated and tuned radials. 
>> Then
>> a shunt fed a 100ft tower with 16 upgraded later to 36 radials.  Modeling
>> indicated little difference. When tested by RBN, the tower was 6 db 
>> better
>> with 16 radials and 8 db better with 36. Well worth the effort.
>>
>> I used to have an inv L with a few 70 ft elevated radials used for both
>> 160m and 80m. The performance was OK on 160m and pathetic on 80m. 
>> There are
>> papers showing that 4 1/8 wave radials on the ground are better than 4 
>> 1/4
>> wave radials.  Perhaps this applies to low elevated radials. Verticals 
>> with
>> short radials need a transformer, not a  balun.
>>
>> Ignacy NO9E
>>
>> On Mon, Mar 15, 2021 at 11:58 AM Patrick Greenlee 
>> <patrick_g at windstream.net>
>> wrote:
>>
>>> What comes to mind is how true to reality is the model's results?  If
>>> the model is relatively true to reality then most of us would likely not
>>> bother with additional radials.
>>>
>>> You said, "It is working great."  Is that a reasonable motivation to add
>>> 4 more radials to maybe get 0.01 more dBi?  The term diminishing returns
>>> comes to mind.
>>>
>>> I would suggest leaving it alone and enjoy using it.
>>>
>>> Have fun.
>>> Patrick       NJ5G
>>> .
>>>
>>> ------ Original Message ------
>>> From: "Dave Sublette" <k4to.dave at gmail.com>
>>> To: "kj6y--- via TowerTalk" <towertalk at contesting.com>
>>> Sent: 3/15/2021 10:26:00 AM
>>> Subject: [TowerTalk] Vertical question
>>>
>>>> Good morning,
>>>>
>>>> I recently changed my elevated 160 meter quarter wave vertical with 
>>>> 8 full
>>>> sized radials to having only 1/8th wave length radials and only four of
>>>> them.  It is working great.  So I thought adding four more radials 
>>>> might
>>>> improve things.
>>>>
>>>> But before I went to all the trouble I decided to model it and see if
>>> there
>>>> was a difference in performance of the 8 radial version compared to 
>>>> the 4
>>>> radial system.
>>>>
>>>> I use a modelling program called Antenna Model.  The result of the
>>>> comparison is this:
>>>>
>>>> The 4 radial system showed a gain of 0.92 dBi with the main lobe at an
>>>> elevation of 20 degrees.
>>>>
>>>> The 8 radial system showed a gain of 0.93 dBi and an identical 
>>>> elevation
>>>> pattern.
>>>>
>>>> My question is:  Why is the gain figure so low?  A dipole exhibits 2.14
>>> dBi
>>>> gain. Why doesn't the vertical show gain?
>>>>
>>>> And lastly, I think these results tell me it isn't worth the effort 
>>>> to add
>>>> four more radials.
>>>>
>>>> Your thoughts?
>>>>
>>>> Thanks & 73,
>>>>
>>>> Dave, K4TO
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