On Sun, 09 Nov 1997 01:54:55 EST k6se@juno.com (Earl W Cunningham)
writes:
>Bill, K0HA wrote:
>> Why is there so much concern on Beverages and Yagis on front-to-back
>>ratio? I always design my Beverages and Yagis to have a small back
>>lobe with two nulls on either side of it to increase the size of the
>>null area...
>====================
>Hi Bill,
>
>I don't know if there is any concern about F/B ratio for Beverages,
>but IMHO, I feel the reason the Beverage is such a good receiving
>antenna is that it's so quiet (it's certainly not because of it's
>negative gain!). And it's quiet merely because it's directional (not
>that it's horizontally polarized, which is untrue -- it responds
>mostly to vertical polarization).
I thought the Beverage responded to low arrival angle signals and
polarization at the TX end was not a concern.
Of course most low angle signals are generated by verticals.
IMO F/B and F/R is very important to the SNR. A lot of noise is created
by others on the band and a reduction in clicks, thumps, phase noise,
splatter, etc is always welcome.
Thanks to you, Tom, Eric and others for adding so much good technical
information to the reflector.
To each his own but it sure beats SWL reports to this "techie".
73 Carl KM1H
>I included the 5-degree elevation angle values because I assume that
>some are interested in decreasing local man-made noise levels coming
>from a specific direction.
>
>The termination resistor value in the models which results in best F/B
>also happens to result in max forward gain and lowest reception angle,
>both of which are good indicators of best directivity, therefore
>lowest noise, no?
>
>Years ago, when I walked one of my Beverages with an FS meter to find
>the best termination value and came up with 300 ohms, and now, when
>finding in the models that 300-350 ohms is best for a Beverage over
>"very poor" soil gives me a clue to the soil conductivity here in the
>Mojave Desert, hi.
>
>73, de Earl, K6SE
>
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