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Re: Topband: 160m portable operating

To: "Top Band group" <topband@contesting.com>
Subject: Re: Topband: 160m portable operating
From: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Tue, 28 Aug 2007 08:47:29 -0700
List-post: <mailto:topband@contesting.com>
On Mon, 27 Aug 2007 17:55:27 -0700 (PDT), steve d wrote:

>Now.. about those antennas? 

I'll strongly endorse the recommendation for a dipole as high as 
you can get it AND a Tee or inverted L vertical loaded against as 
many radials as you can muster. 

ANY dipole you can get up on 160 is going to be a "low" dipole as 
a fraction of a wavelength, so not very directional in the 
horizontal plane, so don't worry about a second one at right 
angles. Also, if it makes it easier to get it high, consider a 
loaded dipole, using loading coils that Barry, KU3X, sells using 
the name "Hypower Antenna Company." I've got three of his antennas 
up in the air, and they work very well and take full power. 

The reason for a vertical AND a dipole is that there are times 
that 160 wants either low angle or high angle radiation. The 
dipole will be pretty high angle, while the vertical will be 
pretty low angle. On any given path, one or the other can easily 
be 10 dB louder. 

For example, when ARRL 160 starts it's 2PM PST, and from here in 
the Bay Area, I can hear WA and CO (800-1,000 miles). I can't work 
them on a dipole at 120 ft, but my 70 ft Tee vertical gets them on 
the first call (the top of the Tee is about 50 ft/leg, and is 
actually a KU3X (Hypower) 80/40 loaded dipole). 

As to radials: more is better, but small wire is fine. I go to an 
electronic surplus house and buy long spools of #18 and #20 
insulated copper. The density of radials close to the feedpoint is 
more important than length, so I'd go for as many 70 ft radials as 
I could. Don't even think about "elevating" radials so you can use 
fewer of them -- the literature says they've got to be at least 
1/8 wave high to give you that benefit -- 67 ft on 160. :) 

A Beverage is easy to build and string from tree to tree using 
electric fencepost insulators. With your QTH, I would point one 
straight west, which will help you pick up mults from the west 
coast. All you need is two ground rods, a spool of wire, a 
transformer, and some coax to feed it into the RX input of your 
radio. 

Power really helps on 160. Consider one of the 500W amps that runs 
on 12V. Run your radio most of the time at 100W, but kick in the 
amp to go S&P for the longer Q's. From a QTH in OH, you'll have 
lots of fun with 100 watts. It's a lot tougher from the west 
coast, because most of the Q's are on the east coast. :)

73,

Jim K9YC


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