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[aprssig] Quad antenna construction techniques

Stephen H. Smith wa8lmf2 at aol.com
Wed Jan 10 05:28:28 UTC 2007


ac7yy at aikenco.net wrote:
> Do you have foil backed insulation in your attic walls and joists?  and if
> so, does that not effect the antenna?
>  
> Kim - AC7YY
>
>
>   
>> -----Original Message-----
>> From: aprssig-bounces at lists.tapr.org [mailto:aprssig-
>> To: vk4tec at tech-software.net; TAPR APRS Mailing List
>> Subject: Re: [aprssig] Quad antenna construction techniques
>>
>> Here's a spreaderless design that uses only 3/4" PVC water pipe, 4-way
>> cross fittings and #14 solid house wire.  This is mounted in my attic
>> crawl space,  and is pointed at a local repeater used for APRN
>> (Automatic Picture Reporting System - combined SSTV & APRS).
>>
>>     < http://wa8lmf.net/2mStealthQuad.jpg >
>>
>>
>>     

This is a 70-year-old cottage with absolutely no insulation anywhere in 
either it's walls or attic.    As you can see in the photo, the rafters 
are completely bare.   The only potential pattern distortion may come 
from the antique single-conductor knob-and-tube electric wiring strung 
through the ceiling joists.     Conveniently the antenna fires out the 
end of the pitched roof, so that even when the roof is soaked with the 
rare (for southern California) rain, signal levels don't vary much.   
Actually, quad antennas are low-Q devices much less affected (and 
detuned) by nearby junk than yagis.




--

Stephen H. Smith    wa8lmf (at) aol.com
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