Call Search
     

New to Ham Radio?
My Profile

Community
Articles
Forums
News
Reviews
Friends Remembered
Strays
Survey Question

Operating
Contesting
DX Cluster Spots
Propagation

Resources
Calendar
Classifieds
Ham Exams
Ham Links
List Archives
News Articles
Product Reviews
QSL Managers

Site Info
eHam Help (FAQ)
Support the site
The eHam Team
Advertising Info
Vision Statement
About eHam.net

   Home   Help Search  
Pages: [1]   Go Down
  Print  
Author Topic: Location High mountains or near ocean  (Read 503 times)
TI2TL
Member

Posts: 17


WWW

Ignore
« on: December 22, 2008, 08:46:58 PM »

I am new to mobile operation but I would like to know just one thing:

would you consider a better location for DX contacts a high mountain (over 7000-8000feet) or on the sand at 10 meters from the ocean? Regardless of the antenna and radio equipment.
 
Logged
WW5AA
Member

Posts: 2088




Ignore
« Reply #1 on: December 23, 2008, 06:19:48 AM »

Salt water is overrated as to ground quality. Usually a small island will show some advantage and then only because of lack of clutter for low angle. If the mountain top is clear of obstructions that is what I would go for. I have worked HF mobile from the beach in California and nearby mountain tops, all within 30 min. Have fun!

73 de Lindy
Logged
K0BG
Member

Posts: 9845


WWW

Ignore
« Reply #2 on: December 23, 2008, 06:52:36 AM »

Lindy is correct. You often see references about how good of DX is possible from near shore line locations. But as Lindy alludes to, it is because of the unobstructed view, more than it is an increase in ground conductivity.

Probably the most important factors with respect to working DX from a mobile are these: Maximize your antenna system; minimize your ambient noise level (ignition RFI, etc.); and the biggest one of all, diligence!!

Alan, KØBG
www.k0bg.com
Logged

WB2WIK
Member

Posts: 20547




Ignore
« Reply #3 on: December 24, 2008, 12:12:04 PM »

The beachfront, if it were a very "flat" location with no mountains nearby at all, would be my choice.  However if it's a beach that has mountains rising nearby, that can be terrible as it's almost impossible to work "over" nearby mountains.

The advantage of a mountaintop on HF is the same as the advantage of a beachfront location: Clear view of a distant horizon, with no nearby obstructions.  Being at 8,000 only makes you 8,000 feet closer to the ionosphere, which really doesn't mean much considering how far away the F2 layer is.

The ground under the antenna system, out to 100 wavelengths or so, is more important I've found.  I'd rather be at the "beach" with excellent ground conductivity than in the mountains with lousy ground conductivity.  However, you can't tell anything about this just by looking at it.  It must be measured.  Thankfully the FCC already has done a lot of measurements and has detailed maps profiling soil conductivity all over the U.S.  I don't know if they have anything like that where you are, but if they do, I'd look at them.

Many VLA radiotelescopes are in the desert at nearly sea level and not on mountaintops, because the RF path loss being 8-10-12-15 thousand feet higher isn't any lower when you're receiving signals from millions of miles away.

What's more important at those EHF frequencies is how clear the atmosphere is, and how low the humidity.

WB2WIK/6
Logged
NH7L
Member

Posts: 30




Ignore
« Reply #4 on: January 06, 2009, 08:52:29 PM »

A number of us in and around Honolulu do a lot of beach HF operating, parked mobile or portable, because of the prevalence of antenna restrictions.

Efficiency seems to depend on how close you are to the water. If you can get your antenna within a quarter wave of salt water, near-magic can happen. If you can't get that close, the mountain may be just as good. On this island, hams have a lot of beach options and only one or two mountaintop options, so the beach is where it's at for most of us.

It also seems to help if your operating spot is on saltwater-saturated ground, such as a beach parking lot built on fill. But even then, closer to the water is better.
Logged
Pages: [1]   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.11 | SMF © 2006-2009, Simple Machines LLC Valid XHTML 1.0! Valid CSS!