[CQ-Contest] ARRL-DX SSB : How were condx ?

Yannick (XV4Y) yannick.devos at online.fr
Thu Mar 8 23:19:39 PST 2012

Hi Tom,

Sorry for the delayed answer.
Gain is over "real ground" as MMana computes it.
The Moxon is around 11dBi when at the exact goal frequency, you quickly loose 1dB when going far from it.
It is a Moxon on 15m but just a dipole on 10m. I got it working on 12m "by luck" with my TS-590s internal ATU doing its job.
I was not expecting high gain on 12m and 10m so 1 S-point compared to the vertical is matching the predictions.
I will soon try to add another reflector element on 10m to have it working like a jungle-job (G4ZU).
The problem is that the modeling don't show a great improvement in gain while I loose all the back lobe.
The reflector element characteristics seem also really touchy and while it will not make the antenna worst in some cases there is no gain at all in adding the element...

We are going a bit out of topic for the "contest" list so I will not tell much more about the antenna.
The truth is also that I am planning to write an article about that and want to keep the detailed undisclosed until it is published...

Thanks for your help.
Yannick DEVOS - XV4Y

Le 7 mars 2012 à 22:18, Tom W8JI a écrit :

> <<<Yes I agree with you that condx can vary greatly with only hundred of miles, especially when condx are tricky. That's why I needed several opinions because it only has a statistical value. I was not asking for a definitive judgement over my antenna choice but more to know if I had to worry or not.>>>>
> They especially vary when the distance is long and the path over or near earth's magnetic poles. :-)
> <<<On 12m and 10m my beam is acting more like an "improved dipole" (8dBi gain calculated) and in practice I only see 1 S-point difference with the GP. Again that's coherent.>>
> Over earth or freespace gain? A dipole should be about 8 dBi over earth, but only about 2.1 dBi freespace. Shouldn't the Moxon be 11 dBi or so over earth, and about 6 dBi freespace? Aren't they around 3 or 4 dBd typically?
> 73 Tom 

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