Cushcraft R7
 

hi just got this ant,what is the best hight to mount this at,
there site says mount 8 feet, will it work better mounted 30 feet of ground
thanks dave browne


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On Wed, 19 May 2004 19:19:21 +0100, "David Browne" dddd@ddd wrote:
hi just got this ant,what is the best hight to mount this at,
there site says mount 8 feet, will it work better mounted 30 feet of ground
Hi David,

It may take a little more adjustment to tune, but that should be the
only down-side. You should at least tune it at 8 feet (or similar,
convenient height) first to confirm its construction.

73's
Richard Clark, KB7QHC

On Wed, 19 May 2004 19:19:21 +0100, "David Browne" dddd@ddd wrote:

hi just got this ant,what is the best hight to mount this at,
there site says mount 8 feet, will it work better mounted 30 feet of ground
thanks dave browne

Don't know the "best" height, but usta live next door to a guy with an
R7, and he mounted it at about 30 feet. It performed fine, as far as
he was concerned. Main downside to the antenna is a fairly narrow
tuning range on 40 meters.

Bob
k5qwg




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On Wed, 19 May 2004 16:40:05 -0700, "Just Another Opinion"
wrote:

Well Thierry your advice is good for a 1/4 wave vertical -- but not a half
wave end vertical.

There is absolutely nothing wrong with Thierry's advise. As the
subject of radials/counterpoise/ground is often either over engineered
or under engineered (often to no apparent difference to the distant
contact). It may complicate the tune, but it may also bring reward.

Lookup the theory and you will see why.

http://www.njqrp.org/n2cxantennas/halfer/

Hi OM,

If someone wants to invest in the treatment that Thierry suggests,
there is no down-side - this "theory" notwithstanding (which, by the
way makes no effort to prohibit it, to its credit). Multiple radials
also serve to decouple the feed line which then provides a more robust
reference against which the antenna operates.

73's
Richard Clark, KB7QHC

Richard, Thierry and the original poster I repeat:

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

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.

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

Do you know what is in the black box matching unit ?? If not see URL:
http://www.iol.ie/~bravo/r7_vertical.htm

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

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

I know this is a controversial subject -- rehashed many times here, mostly
because folks treat the R7 like a quarter wave vertical -- which it isn't
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

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

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

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.
--
From one currently in the Cloaked Mode

Any clod can have the facts, but having opinions is an Art.
Charles McCabe (1856 - ), San Francisco Chronicle






"Richard Clark" wrote in message
...
On Wed, 19 May 2004 16:40:05 -0700, "Just Another Opinion"
wrote:

Well Thierry your advice is good for a 1/4 wave vertical -- but not a
half
wave end vertical.

There is absolutely nothing wrong with Thierry's advise. As the
subject of radials/counterpoise/ground is often either over engineered
or under engineered (often to no apparent difference to the distant
contact). It may complicate the tune, but it may also bring reward.

Lookup the theory and you will see why.

http://www.njqrp.org/n2cxantennas/halfer/

Hi OM,

If someone wants to invest in the treatment that Thierry suggests,
there is no down-side - this "theory" notwithstanding (which, by the
way makes no effort to prohibit it, to its credit). Multiple radials
also serve to decouple the feed line which then provides a more robust
reference against which the antenna operates.

73's
Richard Clark, KB7QHC

Richard, Thierry and the original poster

I also suggest you read the post by Roy Lewallen, W7EL titled
Voltage fed vertical question

--
From one currently in the Cloaked Mode

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

Richard Clark wrote:

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

Did you get up on the wrong side of the bed this morning or something,
Richard?

73, jk

On Thu, 20 May 2004 10:29:41 -0700, Jim Kelley
wrote:

Did you get up on the wrong side of the bed this morning or something,
Richard?

Hi Jim,

Believe in three impossible things before breakfast.

73's
Richard Clark, KB7QHC

Richard Clark wrote in message . ..
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.


Richard,

I don't know the answer to the main issue of this thread. I just
don't know enough about antennas to speak as an expert. However, as a
point of fact, the R7 manual does state on page 1 under the section
titled "Location":

'Although the R7 will operate in almost any location, it will perform
best if it is mounted vertically and located in the clear away from
surrounding objects such as buildings, trees, powerlines, towers, guy
wires, antennas and metallic objects. The R7 should not be attached
to a ground radial system. Failure to heed these points will possibly
degrade performance, detune the antenna and increase VSWR".

When I clicked on the above link, a PDF file was opened. It appears
that the manual was scanned and stored in PDF. In this case, no text
search would be successful.

FWIW, when I added radials to my R7 I was unable to tune it properly
on all the bands. Once the radials were removed I was able to tune it
up without problems.

Thanks,

Rick, K6RJ