[Elecraft] ARRL 160 & Rx antenna

[Bill Coleman]

On Dec 6, 2005, at 8:27 PM, Able2fly at aol.com wrote:

> Would you (or anyone) please elaborate on the use  of an Rx antenna?

The fundamental problem on the low bands is the high noise level. A  
good transmitting antenna can often have S6-9 noise, or worse. It's  
hard to hear weak signals with all that noise.

As W8JI would put it, the characteristics of a good transmitting  
antenna and a good receiving antenna aren't the same. A transmitting  
antenna should have gain in a particular direction (and angle) in  
order to place the most signal into the target area. For receive, at  
least until you get into the upper VHF region, gain isn't really  
important. The problem is noise -- you can pick up the ambient noise  
on the band with barely any antenna at all -- all that gain just  
brings more noise into the radio.

For receive, the important thing isn't gain, but antenna pattern. An  
antenna with a good pattern will ignore noise (and QRM) from  
directions outside the target area. Less noise means better signal to  
noise ratio. Signals that aren't audible on the transmitting antenna  
are then audible on the receiving antenna.

There are many designs for effective low-band receiving antennas.  
These are quite lossy, having gain 20-30 dB below that of a  
transmitting antenna. Examples include Beverage antennas, Flags,  
Pennants, EWEs, K9AY loops. Despite being lossy, they can have quite  
sharp patterns, especially the Beverage antenna.



Bill Coleman, AA4LR, PP-ASEL        Mail: aa4lr at arrl.net
Quote: "Not within a thousand years will man ever fly!"
             -- Wilbur Wright, 1901