On 1/13/2013 9:27 AM, Patrick Greenlee wrote:
It depends...
If reducing QRM and QRN from other directions than your beam heading
produces a higher signal to signal plus noise ratio than optimizing for
max forward gain then minimizing the side and back lobes is the best
choice.
We are looking st 20 - 10 where, "to me" gain is far more important than
f/s. Depending on your location you my have a problem with signals out
of the main lobe. It's not normally a problem on those bands in Central
Michigan.
OTOH below those frequencies f/b and f/s become much more important.
Even arrival angle becomes more important for DX, particularly on the
lower frequencies. A 1/4 wave vertical knocks down close in signals and
does better on DX for 40 and 75 at least for me. I could work stations
on the 40 m vertical that were covered up on the dipole.
So "to me" on 20 - 10 and on average, it depends on your location, type
of operating, and antenna height. Reguardless of which you choose, there
will be times when the other choice would have been better. Still for
the *average* operation and the small differences between the two
configurations on these bands I doubt you would be able to see the
difference. A DXpedition would be something else.
73
Roger (K8RI)
-----Original Message----- From: Barry N1EU
Sent: Sunday, January 13, 2013 5:08 AM
To: Tower Talk List
Subject: [TowerTalk] yagi f/b and rx s/n
I need to come up with some dimensions for 2-element yagis for 20-10M.
I wish to maximize ability to hear weak signals. Does that mean
optimizing f/b ratio, rather than gain? This will be assembled from
SteppIR components that I have on hand, so dimensions can be optimized
for each frequency once a boom length is chosen.
Thanks & 73,
Barry N1EU
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