On a slightly different take, controlling the vertical pattern, ie minimizing
the minor lobes, will have a significant effect on gain as the major lobe now
gets all of the energy. Elevated radials have more to do in establishing the
actual TOA above ground. This is not easy. Try modelling the vertical with
radials in free space and see the TOA move around and the minor lobes move with
the angle of the radials away for 90 degrees. When you have the TOA where you
want it, move the antenna to somewhere AGL and watch the pattern. The ground
losses will now start to absorb the lower portion of the major lobe. The
result will always be a higher TOA unless over VERY conductive ground.
Mel, K6KBE
From: David Gilbert <xda...@cis-broadband.com>
To: elecraft@mailman.qth.net
Sent: Wednesday, July 13, 2016 1:24 PM
Subject: Re: [Elecraft] Sloping Terrain vs Feedline Losses
Lowering takeoff angle.
Regarding the other part, I've stated it as clearly as I can about three
times now. If you disagree or can't follow the point, I don't think
anything else I might say will change that.
73,
Dave AB7E
On 7/13/2016 12:03 PM, Wes Stewart wrote:
> Ok, but I'm unclear about what "improves radiation pattern" means. To
> paraphrase your other premise, "I'm not sure if it does or doesn't but
> if it does, I'm sure it's big" has me wondering. But I wonder about a
> lot of things...
>
>
> On 7/13/2016 10:38 AM, David Gilbert wrote:
>>
>> No, I didn't mean that.
>>
>> If sloping ground improves radiation pattern, it's going to be worth
>> more than 1 db. Pattern changes of any sort typically have
>> significant effect, whereas one db is almost trivial (notwithstanding
>> my own experiments on that on my website). I'm not saying that
>> sloping ground actually has a significant effect ... only that if it
>> has any effect at all it is likely to be greater than 1 db.
>>
>> Dave AB7E
>>
>>
>>
>> On 7/13/2016 10:06 AM, Wes Stewart wrote:
>>> I hope you meant much less than 1 dB.
>>>
>>> On 7/13/2016 1:49 AM, David Gilbert wrote:
>>>>
>>>> Agree on the coax losses, but totally disagree on both of your
>>>> other comments:
>>>>
>>>> 1. Elevated radials will ONLY help reduce near field ground losses
>>>> ... they will do nothing to help radiation pattern. The effects of
>>>> ground conductivity determine far field pattern (given a particular
>>>> profile) no matter what kind of radials he uses.
>>>>
>>>> 2. If there is any gain benefit from the terrain profile at all,
>>>> it will be much more than 1 db.
>>>>
>>>> Dave AB7E
>
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