[Scanner] scanner antenna

[Don]

using 9913 currently and will be studying the situation of gain vs bandwidth

Don
SEMPER VIGILIS
EAGLES  may soar, but weasels don't get sucked into jet engines
http://www.veteransparty.us/MS01.htm Ms Veterans Party
http://www.jcmsara.org Ham radio link
http://myweb.cableone.net/wxfreqrs/  Pascagoula Ms Real Time Observations
----- Original Message ----- 
From: "Edmund F Leavitt" <ed.leavitt at juno.com>
To: <scanner at mailman.qth.net>
Sent: Tuesday, May 17, 2005 5:23 PM
Subject: Re: [Scanner] scanner antenna


> Hi Don,
>
> Nearly all "gain antennas" only provide gain at a relatively narrow range
> of freqs.   If you are using a Ham antenna with 10 dB gain, it probably
> rolls off to zero gain if you go a few MHz out of its intended range.
> Generally speaking, the better the gain, the narrower range of freqs that
> still produce gain.  The only exception that comes to mind is a log
> periodic dipole array (LPDA), where it is both broadband, directional,
> and exhibits gain in varying degrees depending on its design.  Bandwidth
> for an LPDA is typically in the range of several octaves.  Unfortunately,
> LPDAs are apt to be expensive.  The one exception to that would be the
> traditional TV roof antenna, intended for VHF-Lo to UHF.  With that in
> mind, you might consider turning a TV antenna 90° on its boom to make it
> vertically polarized and see if it gives you what need.  Other than that,
> be prepared to dig fairly deeply in your pocket.
>
> I personally have high regard for the much scorned Discone antenna if you
> want omnidirectionality, and gap-free performance over four or more
> octaves.   As with any antenna expected to work UHF, don't "cheap out" on
> the feedline.  For a 50 foot run, 1/2 hardline is probably ideal.  But if
> that's too painful,  the lowest loss braided coaxial cable you can find
> should be used.  I would suggest  LMR400,  Belden 9913 or Belden 9913F7.
> ****************************************************************
> Edmund Leavitt                   Ph:    253 582-5034
> Ham / MARS / FEMA:        KA7UKN / AFA5AH / KPS654
> Lakewood, WA                   N 47° 09'   W122° 31'
> ****************************************************************
>
>
>
> On Tue, 17 May 2005 11:18:45 -0500 "Don" <wxfreqrs at cableone.net> writes:
>> HI ALL
>> looking for the highest gain scanner antenna
>> it will be 40 in the air here on MS GULF COAST
>> prefer a vertical as i don't have a rotator but will consider yagi
>> type if
>> gain is exceptional over my ham antenna of 10.4 which i am using
>> now
>> scanner is bc780xlt
>> Don
>> SEMPER VIGILIS
>> EAGLES  may soar, but weasels don't get sucked into jet engines
>> http://www.veteransparty.us/MS01.htm Ms Veterans Party
>> http://www.jcmsara.org Ham radio link
>> http://myweb.cableone.net/wxfreqrs/  Pascagoula Ms Real Time
>> Observations
>>
>> _______________________________________________
>> Scanner mailing list
>> Scanner at mailman.qth.net
>> http://mailman.qth.net/mailman/listinfo/scanner
>>
>>
>
>
> ****************************************************************
> Edmund Leavitt                   Ph:    253 582-5034
> Ham / MARS / FEMA:        KA7UKN / AFA5AH / KPS654
> Lakewood, WA                   N 47° 09'   W122° 31'
> ****************************************************************
> _______________________________________________
> Scanner mailing list
> Scanner at mailman.qth.net
> http://mailman.qth.net/mailman/listinfo/scanner
>
>
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