Topband: DX on 160, was: Topband QRP WAS

[Tom W8JI]

> On 12/5/2015 5:43 PM, Mark Lunday wrote:
>> Bill, a question about your 160 meter antenna.  I have learned from the 
>> wise
>> old-timers on this message board that a vertical antenna with 
>> broad-banded
>> behavior is a lossy antenna.  Same with a vertical antenna that shows 1:1
>> match.

Some people might believe that myth, but it isn't true.

Bandwidth is a meaningless determinant of efficiency. SWR is meaningless 
also, by itself, in indicating efficiency.

>> Verticals with good efficiency have sufficient ground 
>> radials/counterpoise
>> and present approx 30 ohms impedance and therefore do not provide a 1:1
>> match (I think it's about 1.5:1 or something like that).  In addition, 
>> the
>> efficient verticals are not broad-banded.  Dipoles yes, verticals no. 
>> Also,
>> if your antenna is not a vertical on 160, then as you know it will be an
>> even bigger challenge to work DX on TopBand.

A 1/4 wave tall tower with a perfect ground system will cover all of the 
band with reasonable SWR change. If series fed they will be around 30 ohms 
depending in many things, but that still does not tell us efficiency.

>> efficient verticals are not broad-banded.  Dipoles yes, verticals no. 
>> Also,
>> if your antenna is not a vertical on 160, then as you know it will be an
>> even bigger challenge to work DX on TopBand.

Actually that is exactly backwards, Mark.

Dipoles are narrower than 1/4 wave verticals, all things equal. This is 
because a 1/4 wave vertical has half the resonant length.

73 Tom