[Xastir] Portable Digipeater Antenna?

[Gerry Creager]

Steve Friis wrote:
> Jim Tolbert wrote:
>> When considering adding a portable digipeater to a kit, what does an 
>> antenna mast buy you and what is the relationship between height and 
>> effectiveness?
>> What is antenna height & specifications and equipment specifications 
>> that should be considered for a permanent antenna, centrally located 
>> in the county?
>>
>> We are in Burnett County, Wisconsin ..... according to the U.S. Census 
>> Bureau, the county has a total area of 2,280 km² (880 mi²). 2,128 km² 
>> (822 mi²) of it is land and 152 km² (59 mi²) of it (6.69%) is water.   
>> There are small elevation changes in the county (800 feet to 1440 feet 
>> above mean sea level) and the land is largely forested.
>>
>> Many thanx ............. jt
>>
> My experience shows that doubling the height is equal to multiplying the 
> power by 4. This is especially true if you can get above the tree-tops. 
> Here in the desert, you can really increase the range by adding height. 
> I bring a 25' pole to mount both the HF antenna on plus the dual band 
> VHF/UHF antenna.

My portable repeater exploits suggest that an antenna should be between 
20-40 feet as a minimum... or else just left on the car.  You see 
benefits with antenna height above local terrain that cannot be 
compensated for by either power or preamplification.

I tend to shoot for one of several 30 foot portable masts I have 
available.  One of the simplest is a "bull-float" handle available from 
concrete supply stores (but probably not Home Depot).  they're ~1-3/4" 
diameter threaded poles, 10 ft long.  I've put up to 4 together with 
3-way, single level guying and had the antenna up for as long as a week. 
  Easy to carry and handle, and total cost of the mast was less than 
$80.  Very rugges... they have to be to survive the concrete business.

gerry
-- 
Gerry Creager -- gerry.creager at tamu.edu
Texas Mesonet -- AATLT, Texas A&M University	
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