[Elecraft] NVIS HF vs VHF line-of-sight & CB

[Fred Jensen]

The 1964 Alaska earthquake was a 9.2 centered SSE of Anchorage.  I was 
at Galena AFS at the time, on the Yukon River in the northern interior 
just south of the Arctic Circle. It's fairly flat up there and after we 
realized there was an earthquake, we could watch to the south and it 
appeared that there were ground waves moving rapidly toward us.  It 
ultimately broke off the wooden flag pole in front of the chow hall.

The WW2-era wooden hanger and control tower survived just fine, some 
bookcases toppled and spilled coffee was about all that happened.  The 
reinforced concrete alert hangars ... not so well. Much of the damage in 
Anchorage was the result of liquification of the ancient stream bed 
beneath it.

The effects of any given magnitude earthquake are almost completely 
determined by the conditions at any given place.  We had a couple of 
not-high dipoles and one of those humongous LP arrays for the MARS 
station.  ACS went down, our dipoles worked just fine.  That LP monster 
is basically a poorly optimized 3 element yagi on any given frequency 
and didn't work all that well.

Were I in the EMCOMM business and planning for a major widespread 
disaster situation, I'd focus on the physical aspects of the antennas 
... transportability, survivability, ease of deployment, weight, and the 
like.  The rest will be what it will be, and it will likely be enough 
... at least until better can be arranged.

73,

Fred ("Skip") K6DGW
Sparks NV USA
Washoe County DM09dn

On 4/30/2017 4:15 PM, Walter Underwood wrote:
> Right, an NVIS antenna is effectively a Yagi pointed at the sky. So put a reflector on the dirt.
>
> The Loma Prieta was a 6.9. The Cascadia area could produce a 9.0. Richter is a log10 scale, so that is 100X as strong.
>
> wunder
> K6WRU
> Walter Underwood
> CM87wj
> http://observer.wunderwood.org/ (my blog)
>