Topband: Use shunt fed tower

[GEORGE WALLNER]

I think the issue is not whether a vertical needs radials or not.
A vertical monopole needs a ground system or a counterpoise. The ground 
system can be the actual ground or radials, or both, or even the shield of 
the coax (and your station at the end of it). If you have a good ground and 
it is connected via a low impedance path, you may not need any radials. (I 
don't use any at C6AGU, but the antenna stands in salt-water.) But if your 
ground is poor, you do need radials, or some other effective counterpoise. 
Every location is different and you should plan accordingly.
It is very simple to determine whether your ground system is adequate. Model 
and measure your antenna. If the model indicates a feed point impedance of 
25 Ohms and you measure 50 Ohms, the extra 25 Ohms is probably contributed 
by the (poor) ground system. (Of course it could be a poor model too.)
73,
George,
AA7JV

On Sun, 16 Sep 2018 10:11:06 -0400 (EDT)
  kolson at rcn.com wrote:
>
> Well, my system here at K3OX is a "T" with a 40 ft vertical section and a 90 ft flat top. It sort of worked OK when I first put it up, but it works much more OK after about 32 random (to fit my 4 0 x 110 lot) radials were installed. It would work better yet if I had more and longer radials, and mo' better than that  if the vertical section was 130 ft! 
>
> So saying an antenna "works" is a relative thing. But the moral is, you do what you can. T o paraphrase Clint Eastwood, "A man's gotta know his antenna limitations". 
>
> 73 Kevin K3OX 
>
>
> ----- Original Message -----
>
>From: "Peter Voelpel" <dj7ww at t-online.de> 
> To: topband at contesting.com 
> Sent: Sunday, September 16, 2018 9:44:46 AM 
> Subject: Re: Topband: Use shunt fed tower 
>
> It can work and it does. 
>
> I used a shunt fed tower without radials for a couple of years on the former 
> qth just with the tower grounding. 
> Now I feed the tower directly and against a single sloping radial, it works 
> great and is also a better receiving antenna then my relatively short 
> beverages. 
>
> 73 
> Peter, DJ7WW 
>
> -----Original Message----- From: Topband [mailto:topband-bounces at contesting.com] On Behalf Of John 
> Harden, D.M.D. 
> Sent: Sonntag, 16. September 2018 02:43 
> To: daraymond at iowatelecom.net 
> Cc: topband at contesting.com; cfytech24x7 
> Subject: Re: Topband: Use shunt fed tower 
>
> A shunt fed tower requires radials period. It cannot work without them! 
>
> 73, 
>
> John, W4NU 
>
> Sent from my iPhone 
>> On Sep 15, 2018, at 1:55 PM, <daraymond at iowatelecom.net> 
> <daraymond at iowatelecom.net> wrote: 
>>
>> It makes no difference how the tower is fed, a vertical antenna must have 
> radials of some kind to be effective.      73. . .Dave, W0FLS 
>>
>> -----Original Message----- From: cfytech24x7 
>> Sent: Saturday, September 15, 2018 11:29 AM 
>> To: topband at contesting.com 
>> Subject: Topband: Use shunt fed tower 
>>
>> A shunt fed tower is a vertical antenna so it offers lowest take off 
> angle. Shunt feeding avoids need for radial field.  Any horizontal wire 
> antenna is going to put most of your radiated energy out at high angles, 
> unless you can get it at least a half wavelength of height.  A loop may be a 
> quieter antenna for RX but your existing inverted Vs are no doubt better for 
> TX. 
>> There is some art and experimentation involved in the matching but the 
> results will be worth the effort.  I  would start with your highest antenna 
> for top band, next highes for 80m. Note that your yagis will act nicely as 
> capacitive hats to add to effective tower hight. 
>> Gl es 73, ab1vl chuck 
>>
>>
>> Sent from my Galaxy TabR A 
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