On 5/24/11 6:53 AM, Eddy Swynar wrote:
>
> On 2011-05-24, at 9:34 AM, Jim Lux wrote:
>
>> The former does things "because we've done it that way in the past
>> and it worked".
>
> Hi Jim,
>
> I fear that that very same mantra seems to prevail now re. radials,
> only in reverse...
>
> Specifically, "...Put in as many radials as you can. PERIOD." Well,
> to a newcomer, just how many is "as many"...? And what's the best
> length for what you put in...?
>
> So many EZNEC-armed experts to-day have come to embrace the very
> thing they espouse to deplore, i.e. they've come to "...Doing things
> (LAYING RADIAL FIELDS) because we've done it that way in the past (AS
> MANY AS POSSIBLE. PERIOD) and it worked (I'M #1 IN THE ARRL DXCC
> STANDINGS FOR 160)."
>
> All I'm saying---rather poorly, too, obviously!--is that there are
> actual quantitative measurements to be seen/had as a guide to
> newbies...simply stating that "...put in as many radials as you can!"
> just doesn't cut it anymore, and is short-changing guys who are just
> beginning to explore this facet of the antenna world.
>
The challenge, as I see it, is not in the actual quantitative data (as
you say, there's plenty out there) but in the guidance for interpretation.
And that's so subjective.. Most hams don't have a $/dB improvement
metric (because your expenses are spread out over time and your budget
goes up and down.. "Hey, I just got a bonus, I'm going to buy a toy")
and because the value of your labor also fluctuates.
I imagine that if you lived in Cleveland, laying radials in Februrary
would have a very high perceived labor cost (you'd have to shovel the
snow out of the way, for one thing, but as an activity for Memorial day
weekend, might be very different.
So, while we might know that changing a radial field in a particular way
might reduce losses by 1 dB, you need to trade that against replacing
that cheap RG-58 you scavenged from an old network installation with
decent coax.
And, of course, what's 1 dB worth? To an EME'er looking for their 100th
QSO, quite a lot. To someone running a 5 element Yagi on 10 meters at
the solar cycle peak, not a heck of a lot.
I think that's where some of the "you have to do X" kind of advice comes
from. Someone who's already done everything else is looking for small
incremental changes.
And, take a typical suburban installation: a 100 W transceiver with a
inconspicuous vertical in the back yard, and maybe a dipole strung along
the fence or among the trees; there's SO many aspects that "could be
improved" that the ham is faced with a lot of conflicting advice. Do
you spend time laying radials? Or raise the antenna? or put in elevated
radials? Or put a tuner at the base? Or just buy an amp?
In some ways, that's part of the fun; it's also part of the frustration.
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