[CQ-Contest] Contest QTH, hilltop or seaside?

[Steve London]

On 01/03/2015 04:18 PM, Jim Brown wrote:
> On Sat,1/3/2015 12:03 PM, Steve London wrote:
>> If you are playing with HFTA, I strongly urge you to do a sensitivity
>> analysis by changing your datapoints, randomly, by 1 to 3 feet. Do
>> this on each band of interest. If the results change significantly,
>> then HFTA is not a valid model at your QTH.
>
> I believe that's an incorrect conclusion, Steve. N6BV, HFTA's author,
> recommends making multiple runs to rule out the granularity issue that
> you noted

> That is, he suggests modeling not at single heights or
> azimuths, but at multiples of both.

I did not see the granularity by changing heights in small increments, 
only changing the terrain profile by insignificant amounts.

> He advises that it IS possible to
> have a condition that yields bogus results, but by doing those multiple
> calcs, it's easy to weed them out.
>
> For my QTH, which is far more irregular than yours,

That's quite a sweeping statement coming from someone who has never been 
to my QTH. Nor have I been to your QTH.

> I modeled in 5
> degree steps from 0 to 45 degrees, at 5 ft height increments. Knowing my
> terrain, he also recommended going out something like 10 miles or more.
> Many of us out here in the Bay area have used HFTA extensively, and
> swear by it.

I bet very, very few have put up a reference antenna to compare against. 
They run HFTA. Put up antennas. Guys tell them they have a good signal. 
That HFTA must be great !

73,
Steve, N2IC