I think I see why you said what you did, Tom. If we replace the two
elevated radials under our inverted-L with an FCP, and the bandwidth gets a
little narrower, then yes, that doesn't prove that we've improved the
efficiency. Only FS measurements will, unless I've forgotten something
(again).
In most cases on this reflector, an earth radial system is being discussed,
and the quoted statement made to me off-list is generally true. But you
knew that. :-)
I thought I remembered reading a comparison between what I have (a 155'
inverted-L with the vertical portion 55' high and two 10' high 1/4 wave
radials) and someone who replaced their radials with an FCP. I remember
thinking that the resulting reduced bandwidth is too narrow for my
interests.
Maybe someone can refresh my memory.
73, Mike
www.w0btu.com
On Mon, Oct 28, 2013 at 11:56 AM, Tom W8JI <w8ji@w8ji.com> wrote:
> Thanks, but I realized that. I was just curious, because somewhere I read
>> that the FCP had a slightly narrower bandwidth than a couple of elevated
>> radials.
>>
>>
>> Mike, The wider the bandwidth the less effective the antenna is. A good
>>
>>> xmit antenna on 160 may have a 2:1 VSWR range
>>> of perhaps 30 to 40 KHz.
>>>
>>
>
> Actually, that statement isn't true at all. That claim is a complete
> misstatement of rules. I'm surprised anyone repeats it or believes it.
>
> Bandwidth by itself has nothing to do with efficiency or gain. We can have
> antennas 5 kHz wide that have less than 1% efficiency, and antennas 500 kHz
> wide that are nearly 100% efficiency.
>
> As a matter of fact, as a ground systems get better, it is entirely
> possible for the same antenna to have more bandwidth. It is, of course,
> possible to do the opposite.
>
> Why focus on something meaningless, other than describing bandwidth as an
> operating convenience?
>
> 73 Tom
>
_________________
Topband Reflector
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