On Thu, 20 May 2004 08:14:18 -0700, "Just Another Opinion"
wrote:

Richard, Thierry and the original poster I repeat:

Repetition is both tedious and changes nothing.

The R7 is NOT a quarter wave vertical -- it is a half wave end
fed antenna.

Mantras soothe the soul certainly.

A quarter wave radiator needs a ground plane or radials to work against for
sure -- but Cushcraft sez a half wave antenna doesn't need radials as it is
like a horizontal dipole turned vertical and end fed (high impedance) rather
than center fed.

Not needing and prohibiting are not the same thing.

I suggest you read and study the following:

The Cushcraft manual it explicitly states "The
R7 should not be attached to a ground radial system".
URL: http://www.cushcraft.com/support/pdf/r7.pdf

Yeah, and page one:
"System Grounding"

One radial good.
More radial bad.
Yeah, sure.

In fact a word search against the quote above returns 0 hits. So much
for explicit statements and what "should" be read. I note the links
below have the same breathless nature, which is to say a lot of air.

Do you know what is in the black box matching unit ??

Yes I do.

If not see URL:
http://www.iol.ie/~bravo/r7_vertical.htm

Another "should" be read? I think not. It's been posted here many
times over the years and doesn't even broach the topic (the word
"radial" appears nowhere).

A local Ham added radials -- couldn't tune the antenna -- so he added a
tuner. When he ran a kilowatt into this mishmash -- the black box blew up.
So he repaired it as in URL:
http://www.iol.ie/~bravo/r7_vertical.htm

And this proves what (besides a penchant for repetition)? Another
anonymous lid? Thanks, but no thanks, we have our quota here; too
often appearing in the guise of learned lecturer complete with Cliff
notes. This doubly quoted link does not describe the event you allude
to, and in fact offers trap construction is more problematic than the
invention of radials-as-evil.

He no longer has the added radials and tuner and runs a KW all the time with
no ill effects -- let the experimenter beware.

Yeah, now there's a line - no experimentation in Amateur radio. We
have enough Credit Card operators.

I know this is a controversial subject -- rehashed many times here

Ah, the voice of experience. I've been here 10 years and haven't seen
this soap opera yet.

mostly because folks treat the R7 like a quarter wave vertical -- which it isn't

Repetition again, quite boring now.

and the R7 has that complex matching black box design which I wouldn't mess
with by adding radials. Unless I had the proper test equipment and expertise
to determine what effect added radials have on the impedances and matching.
Cushcraft undoubtedly did this.

More at URL:
http://lists.contesting.com/archives.../msg00059.html

"There is no grounded part in an R7 type antenna"

Which, of course, negates page one of the quoted manual above....

AND http://dayton.akorn.net/pipermail/to...ch/037180.html

"The R7, like others in the R3-R8 series from
Cushcraft, use some number of 39" 'radials'...
They are not radials"

Quality stuff there.

Again, nothing here evidences the "should" of the "should" be read.
The two quotes above offer repetition and no actual technical
discussion. But then, this group is the place for that, and rightly
so in the face of such tepid offerings.

You should vet your offerings before submitting them as evidence.

Regarding decoupling the feed line -- Cushcraft recommends an RF choke 8
inches in diameter and ten turns on the coax.

Excellent advice for the 1960s. However, in the 21st century most
correspondents here would appreciate how mediocre-to-poor that would
be with a conventional choke looking into a half wave load.

You seem to be at odds with experimentation with this last piece of
advice. The link to the match box above suggests a far different
means of choking. As this choking method does not appear in the
Cushcraft liturgy, are we to assume the antenna will burst into
demonic flames if this un-ordained device is used?

Me -- I trusted Cushcraft and followed their instructions. Been working
great for 6 years now.
I won't run out the brag tape on countries worked with it -- means nothing.

That has been demonstratively true here for years.

Now, demonstrate the difficulties that will be imposed (if one follows
Thierry's advice) by constructing a model readable by EZNEC that may
be offered here for peer review. Testimonials do not pass as evidence
in this forum as so many of them for the eh/cfa/fractal clog the
system currently.

73's
Richard Clark, KB7QHC