Ignacy,
I did notice that you were planning for elevated radials.
Be aware that the gain and F/B of the array is very sensitive to parasitic loss.
Ground loss will quickly diminish the current in the parasitic and the gain
will crash.
It’s easy to model this. Just include a series resistance in the parasitic
element and watch the gain and F/B drop.
Field measuring the gain with on air tests can be difficult. With only 3 or 4
dB forward gain compared to the single vertical, it can be very hard to
measure. Even using RBN reports, QSB can easily mask this small change.
However, 3 dB is, well…..3dB and it's like doubling your TX power. For the
really weak QSOs, when your signal is just bubbling around the noise, that 3dB
can make the QSO.
I recommend you read about my tuning method. It is not a trivial process to
tune the parasitic to match the model.
73, de steve ve6wz
> On Jan 27, 2022, at 9:04 AM, Ignacy Misztal <no9e@arrl.net> wrote:
>
> Steve,
>
> Excellent work and sorry for missing it.
>
> I was thinking about a quick design. Elevated radials, not 100 ground ones. T
> coming from top of tower on ropes. Also 30m spacing so SWR changes less
> compared to the 20m and can be handled without extra matching by a tuner. If
> 4.5 db becomes 3 db it is still OK. If it drops to 1 db, not worth the
> effort. Perhaps I will experiment for the upcoming CQ 160 contest and report.
>
>
> Ignacy, NO9E
>
> On Thu, Jan 27, 2022 at 10:43 AM VE6WZ_Steve <ve6wz@shaw.ca
> <mailto:ve6wz@shaw.ca>> wrote:
> Yes.
> I wrote this paper about it. I talk about about modelling, design,
> construction and about tuning the array:
> https://drive.google.com/file/d/1eVklkZtlJW93JIJ9oDqbCyl-Jkik6YEX/view
> <https://drive.google.com/file/d/1eVklkZtlJW93JIJ9oDqbCyl-Jkik6YEX/view>
>
> 73, de steve ve6wz
>
>> On Jan 27, 2022, at 8:17 AM, Ignacy Misztal <no9e@arrl.net
>> <mailto:no9e@arrl.net>> wrote:
>>
>> I am trying to get some gain on 160m where currently I have a shunt fed
>> 100m tower. It works well but is not spectacular.
>>
>> I modeled a reflector some 100 ft away from the tower. Either as inv L with
>> one elevated radial or T with two elevated counterpoises. EZNEC shows up to
>> 4 dB gain as a reflector and up to 3 dB as a director. Is this realistic?
>> Has anybody done anything like that?
>>
>> Ignacy NO9E
>> _______________________________________________
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