Topband: New guy here. Low noise rx antenna for 1/2 acre lot?

[Guy Olinger, K2AV]

" I have noticed that my G5RV picks up about HALF the noise that the 
K9AY loops do, and when I try to use my pre-amp (ICE, 1800-2000kHz) 
with the loops all it does is amplify the noise. The signal/noise 
ratio remains the same, if not lower because now it is louder!!!"

The quote above makes me wonder about how you measured. You need to be 
sure that you are not just comparing the absolute levels of noise on 
your horiz vs. the K9AY.

Listen to a fairly weak signal in the desired direction on the horiz 
ant and note the DIFFERENCE between the desired signal and the noise 
on THAT antenna. Then do the same on the K9AY. The K9AY is working for 
you if the DIFFERENCE ON THE LOOP is better than the DIFFERENCE ON THE 
HORIZ.

Having the preamp on all the time while making a difference 
measurement should return the same result as measuring all the time 
with it off. If not, use the preamp on/off setting for the antenna 
that returns the largest difference.

Except in substantial improvement situations, measuring and comparing 
signal/noise usually can't be done well without some equipment, either 
a scope (hardware or audio card based) or peak-reading audio voltmeter 
calibrated in db's. And, of course, receiver AGC needs to be off.

It would not be at all uncommon for a by-ear comparison of two 
signal/noise differences to miss a signal/noise change of four or five 
db. Particularly so if the absolute signal levels differ on the two 
antennas.

It is better to use equipment to measure signal/noise and let those 
measurements "calibrate" your ears over time, than to assume your not 
hearing a change means there is no difference.

(Been there, done that, been fooled, shame-on-me, yada, yada.)

73, Guy.




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