[TowerTalk] Another Ground Radial Question

[pehaire]

I agree with you.

In Beer's article on using different verticals in a 2 element phased array 
by varying the lenght of the feed line to each vertical, he uses radials and 
he pointed out that when radials crossed he bonded them together.

It looks like to me that a half square could be thought of as 2 verticals
 each with one radial and the 2 radials attached or bonded together at their 
ends.  Thus 2 verticals spaced a halfwave apart.

Noll in his book describes 2 verticals spaced almost a half wave and fed 
with  300 ohm line and has a switch in the center of the 300 ohm line that 
he can go from end-fire to broadside.  The close spacing I guess is to 
reflect the velosity factor of the 300 ohm line. The close spacing causes a 
slight loss  in gain. But who cares about plus or minus one db.  That is one 
sixth of an S unit.  Or you could increase power by one fourth and more than 
make up for the loss.

WA5MUE
 ----- Original Message ----- 
From: "Kelly Taylor" <ve4xt at mts.net>
To: "pfizenmayer" <pfizenmayer2 at q.com>
Cc: <towertalk at contesting.com>; "WA8JXM" <wa8jxm at gmail.com>
Sent: Monday, May 23, 2011 9:20 PM
Subject: Re: [TowerTalk] Another Ground Radial Question


> Is it not possible to discuss this question by considering the design of 
> two UHF verticals mounted on a car?
>
> The corollary of the original question would then suggest this is not 
> possible, since you do not have separate radial fields (since the car IS 
> the radial field).
>
> But we do know it is possible, because we see examples of it at every 
> hamfest, every field day and many emcomm events.
>
> I would suggest that it is never a bad thing to get as close as you can to 
> the theoretical "perfect" radial field (an infinite plane of copper). Even 
> if that means two antennas share the radial field.
>
> But overlapping isn't necessary: where any wires meet, cut them and bond 
> them to each other.
>
> Don't ask me for the math: K9YC I ain't!
>
> 73,
> Kelly
> Ve4xt
>
> Sent from my iPhone
>
> On May 23, 2011, at 7:46 PM, "pfizenmayer" <pfizenmayer2 at q.com> wrote:
>
>>
>>
>>
>>> "terminated in a common bus".  I take that to mean they are tied 
>>> together
>>> rather than overlap without touching?
>>>
>>> Ken
>>>
>>> On Mar 18, 2011, at 5:08 PM, pfizenmayer wrote:
>>>
>>>> Antenna Engineering Handbook by Jasik says -
>>>>
>>>> " Individual ground systems are required for each tower of a 
>>>> multielemnt
>>>> array . If the individual systems would overlap , the adjoining systems
>>>> are
>>>> usually terminated in a common bus."
>>>>
>>>> Under fig 20-16 showing radial systems for a two element array - It 
>>>> goes
>>>> on
>>>> to state " The adjoining systems  do not overlap but are terminated in 
>>>> a
>>>> common bus."
>>>>
>>>> E.A. LaPort's Radio Antenna Engineering shows the exact same situation 
>>>> .
>>>
>> Yes - nothing overlaps without touching  -  visualize two  radial fields
>> lying so they overlap at about 1/4 of the diameter , then draw a straight
>> line across where they overlap perpendcular to a line between the centers 
>> of
>> each field ,  along that line all the radials are terminated and tied to 
>> a
>> common bus.
>>
>> Sure wish we could attach a drawing -
>>
>> Hank K7HP
>>
>>
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