[Antennas] Quick Question. I hope.

Wed Nov 1 12:18:43 EST 2006

Again not true.
I have a colinear dual band vertical at home.
It's 3 - 5/8ths wave sections and has a ground plane.
I have a 5/8 over 5/8 wave colinear mobil antenna
that does need a ground plane. 
I have a colinear mobile antenna 1/2 wave over 1/2 
wave and it does not need a ground plane. I have a 
1/2 wave vertical for 10m that does not need a ground 
plane. 1/2 wave verticals do not need a ground plan...
They have a matching section. Odd multiple 1/4 wave
antenna require a ground plane or the equivilant matching
section.
73,
Jon
KD5SFA
-----Original Message-----
>From: Jim Miller <JimMiller at STL-OnLine.Net>
>Sent: Nov 1, 2006 12:12 PM
>To: DavidE Benedict <iam at pmug.org>, antennas at mailman.qth.net
>Subject: Re: RE: [Antennas] Quick Question. I hope.
>>NOT true. ONLY "Collinear" antennas do not need a ground plane. ALL other
>mobile antennas or verticals require a ground plane. I think you have just
>realized your SWR problem. Provide the ground plane and you should have the
>SWR come in. The ground plane (at least for test purposes) can be simply 3
>or 4 wires of 19 inch length connected at the feed point to the shield side
>of the coax.
>>73, Jim
>>----- Original Message ----- 
>From: "DavidE Benedict" <iam at pmug.org>
>To: <antennas at mailman.qth.net>
>Sent: Wednesday, November 01, 2006 10:31 AM
>Subject: Re: RE: [Antennas] Quick Question. I hope.
>>>CBoone at earthlink.net writes:
>>Indoor antennas are always a pain....especially for 6m....2 should be easy
>>to do BUT remember, an indoor antenna has a 12db loss compared to the same
>>antenna outside!! 12db is a 20:1 power level.....IF you can run a single
>>coax outside, try putting a 5/8wave antenna on a good ground plane (54in
>>radials)....that will work on both 2 and 6mtrs and the higher the
>>better...even a small RG58 run can be done through most windows
>>thresholds...
>>Likely you have some metal in the vicinity of the indoor antennas....or
>>the
>>ground plane is not sufficient...
>>>>Chris
>>WB5ITT
>>(also running a 857D on 6 and 2 using a NMO150 on top of the company van
>>;)
>>>Hmmmm...where does that 12db loss come from just by being indoors?
>...doesn't sound right.
>>My understanding is that 5/8 wave ant does not need radials or groundplane.
>>David B.
>W7DBH -Mobile Only
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