[NLRS] The Twin Cities - Milwaukee VHF path

[Gerald]

On Sun, 2005-06-19 at 08:43 -0400, W0ZQ at aol.com wrote:
> 
> I think the North-South paths are "better" tropo paths then east-west  paths. 
>   I think this is generally true for those of us that live in  the Upper 
> Midwest.    Tropo to OK and TX is more common than PA  and NY.   I think its just 
> the way the weather patterns work.
>  
> For day to day scatter, corn country is better than pine tree  country.   Not 
> sure why, perhaps its a reflection of the "average"  humidity levels.   When 
> roving, I've noticed good propagation  from EN23/24, but not so good from 
> EN35/36.   Most rovers agree that  its tough roving in EN26/36/46 while EN22/32/42 
> is rover  heaven.    
>  
> The Twin Cities - Milwaukee path is over pine tree country.   
>  
> 73, Jon
> W0ZQ
> ____

Long range VHF and up propagation takes inverted temperature gradients
and maybe humidity gradients and those only stay with very light winds.
Significant winds (few mph up) mix the layers and prevent the inversions
and gradients. The temperature gradient inversions seem to come from
radiant cooling during calm nights to be strongest at daybreak because
the heating of the sun tends to cause local breezes to mix the inversion
away.

The evening blobs of weather radars, I don't yet understand. They don't
seem to show enhanced VHF propagation, they don't stand still, yet they
seem strong to be insects as suggested by NWS.

-- 
73, Jerry, K0CQ
Dr. Gerald N. Johnson, electrical engineer
All content copyright, Dr. Gerald N. Johnson