Discussion:
Cushcraft R7
(too old to reply)
David Browne
2004-05-19 18:19:21 UTC
Permalink
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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Richard Clark
2004-05-19 19:45:38 UTC
Permalink
Post by David Browne
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
unknown
2004-05-19 20:31:20 UTC
Permalink
Hi,

I used one.
At ground level it needs many flexible radials burried into the ground to
give good results.
Then I placed it on top of a small tower 10m high without its flexible
radials, the result is much better.
I remember than R1ANF was on 20m, I call him in SSB only a few seconds
using my TX barefoot, and I had my QSL !
This is not a proof that the R7 works well, but in all cases, there is
nothing to tell against it. This is probably one of the best vertical on the
place.
But try to place it in height, that will improve the radiation pattern.

about radials : http://www.astrosurf.com/lombry/qsl-radials.htm

73
Thierry, ON4SKY
http://www.astrosurf.com/lombry/
Post by David Browne
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
---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.688 / Virus Database: 449 - Release Date: 18/05/2004
Just Another Opinion
2004-05-19 21:59:41 UTC
Permalink
Au Contraire -- this is NOT a quarter wave vertical -- it is a half wave end
fed antenna and if you read the Cushcraft manual it explicitly states "The
R7 should not be attached to a ground radial system". The feed point is a
high impedance point and the black box matches the 50-Ohm coax to this high
impedance - thus no radials are required -- in fact adding radials will
screw up the antenna.

As for height -- mine is 8 feet off the ground and works very well. A friend
had one up about 25 feet and we got very nearly the same reports in on the
air checks. BUT -- there are a lot of variables in all this -- ground
conductivity, obstructions, terrain, etc -- so mounting higher MAY give
better results -- I know users who found this to be true at their location.

BUT if increasing height will help clear obstructions -- then by all means
mount it up higher.

The flexible rods at the bottom of the antenna are according to Cushcraft
"Counterpoises" to isolate the antenna from ground. They are not long enough
to be resonant radials on any band.

Before doing anything -- READ THE MANUAL!
URL:
http://www.cushcraft.com/support/pdf/r7.pdf

Your results may vary -- let the reader beware.
--
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
Post by unknown
Hi,
I used one.
At ground level it needs many flexible radials burried into the ground to
give good results.
Then I placed it on top of a small tower 10m high without its flexible
radials, the result is much better.
I remember than R1ANF was on 20m, I call him in SSB only a few seconds
using my TX barefoot, and I had my QSL !
This is not a proof that the R7 works well, but in all cases, there is
nothing to tell against it. This is probably one of the best vertical on the
place.
But try to place it in height, that will improve the radiation pattern.
about radials : http://www.astrosurf.com/lombry/qsl-radials.htm
73
Thierry, ON4SKY
http://www.astrosurf.com/lombry/
Post by David Browne
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
Post by David Browne
thanks dave browne
---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.688 / Virus Database: 449 - Release Date: 18/05/2004
unknown
2004-05-19 22:53:01 UTC
Permalink
Post by Just Another Opinion
Au Contraire -- this is NOT a quarter wave vertical -- it is a half wave end
fed antenna and if you read the Cushcraft manual it explicitly states "The
R7 should not be attached to a ground radial system". The feed point is a
high impedance point and the black box matches the 50-Ohm coax to this high
impedance - thus no radials are required -- in fact adding radials will
screw up the antenna.
I always used radials when using ANY vertical at ground level successfully,
whatever write manuals.
I laways use counterpoise when erected in heights, and in both cases,
results are there.
Post by Just Another Opinion
As for height -- mine is 8 feet off the ground and works very well. A friend
had one up about 25 feet and we got very nearly the same reports in on the
air checks. BUT -- there are a lot of variables in all this -- ground
conductivity, obstructions, terrain, etc -- so mounting higher MAY give
better results -- I know users who found this to be true at their location.
BUT if increasing height will help clear obstructions -- then by all means
mount it up higher.
The flexible rods at the bottom of the antenna are according to Cushcraft
"Counterpoises" to isolate the antenna from ground. They are not long enough
to be resonant radials on any band.
Before doing anything -- READ THE MANUAL!
http://www.cushcraft.com/support/pdf/r7.pdf
Your results may vary -- let the reader beware.
--
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
Post by unknown
Hi,
I used one.
At ground level it needs many flexible radials burried into the ground to
give good results.
Then I placed it on top of a small tower 10m high without its flexible
radials, the result is much better.
I remember than R1ANF was on 20m, I call him in SSB only a few seconds
using my TX barefoot, and I had my QSL !
This is not a proof that the R7 works well, but in all cases, there is
nothing to tell against it. This is probably one of the best vertical on
the
Post by unknown
place.
But try to place it in height, that will improve the radiation pattern.
about radials : http://www.astrosurf.com/lombry/qsl-radials.htm
73
Thierry, ON4SKY
http://www.astrosurf.com/lombry/
Post by David Browne
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
Post by David Browne
thanks dave browne
---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.688 / Virus Database: 449 - Release Date: 18/05/2004
Just Another Opinion
2004-05-19 23:40:05 UTC
Permalink
Well Thierry your advice is good for a 1/4 wave vertical -- but not a half
wave end vertical.

Lookup the theory and you will see why.

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


--
From one currently in the Cloaked Mode
Post by unknown
Post by Just Another Opinion
Au Contraire -- this is NOT a quarter wave vertical -- it is a half wave
end
Post by Just Another Opinion
fed antenna and if you read the Cushcraft manual it explicitly states "The
R7 should not be attached to a ground radial system". The feed point is a
high impedance point and the black box matches the 50-Ohm coax to this
high
Post by Just Another Opinion
impedance - thus no radials are required -- in fact adding radials will
screw up the antenna.
I always used radials when using ANY vertical at ground level
successfully,
Post by unknown
whatever write manuals.
I laways use counterpoise when erected in heights, and in both cases,
results are there.
Post by Just Another Opinion
As for height -- mine is 8 feet off the ground and works very well. A
friend
Post by Just Another Opinion
had one up about 25 feet and we got very nearly the same reports in on the
air checks. BUT -- there are a lot of variables in all this -- ground
conductivity, obstructions, terrain, etc -- so mounting higher MAY give
better results -- I know users who found this to be true at their
location.
Post by Just Another Opinion
BUT if increasing height will help clear obstructions -- then by all means
mount it up higher.
The flexible rods at the bottom of the antenna are according to Cushcraft
"Counterpoises" to isolate the antenna from ground. They are not long
enough
Post by Just Another Opinion
to be resonant radials on any band.
Before doing anything -- READ THE MANUAL!
http://www.cushcraft.com/support/pdf/r7.pdf
Your results may vary -- let the reader beware.
--
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
"Thierry" <Answer direct via http://www.astrosurf.com/lombry/post.htm>
Post by unknown
Hi,
I used one.
At ground level it needs many flexible radials burried into the ground
to
Post by Just Another Opinion
Post by unknown
give good results.
Then I placed it on top of a small tower 10m high without its flexible
radials, the result is much better.
I remember than R1ANF was on 20m, I call him in SSB only a few seconds
using my TX barefoot, and I had my QSL !
This is not a proof that the R7 works well, but in all cases, there is
nothing to tell against it. This is probably one of the best vertical on
the
Post by unknown
place.
But try to place it in height, that will improve the radiation pattern.
about radials : http://www.astrosurf.com/lombry/qsl-radials.htm
73
Thierry, ON4SKY
http://www.astrosurf.com/lombry/
Post by David Browne
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
Post by David Browne
thanks dave browne
---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.688 / Virus Database: 449 - Release Date: 18/05/2004
Just Another Opinion
2004-05-19 23:53:06 UTC
Permalink
Well Thierry -- your advice is good for a 1/4 wave vertical -- but not a
half
wave end-fed vertical.

Look at the theory and you will see why.

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


--
From one currently in the Cloaked Mode
Post by unknown
Post by unknown
Post by Just Another Opinion
Au Contraire -- this is NOT a quarter wave vertical -- it is a half wave
end
Post by Just Another Opinion
fed antenna and if you read the Cushcraft manual it explicitly states
"The
Post by unknown
Post by Just Another Opinion
R7 should not be attached to a ground radial system". The feed point
is
Post by unknown
a
Post by unknown
Post by Just Another Opinion
high impedance point and the black box matches the 50-Ohm coax to this
high
Post by Just Another Opinion
impedance - thus no radials are required -- in fact adding radials will
screw up the antenna.
I always used radials when using ANY vertical at ground level
successfully,
Post by unknown
whatever write manuals.
I laways use counterpoise when erected in heights, and in both cases,
results are there.
Post by Just Another Opinion
As for height -- mine is 8 feet off the ground and works very well. A
friend
Post by Just Another Opinion
had one up about 25 feet and we got very nearly the same reports in on
the
Post by unknown
Post by Just Another Opinion
air checks. BUT -- there are a lot of variables in all this -- ground
conductivity, obstructions, terrain, etc -- so mounting higher MAY give
better results -- I know users who found this to be true at their
location.
Post by Just Another Opinion
BUT if increasing height will help clear obstructions -- then by all
means
Post by unknown
Post by Just Another Opinion
mount it up higher.
The flexible rods at the bottom of the antenna are according to
Cushcraft
Post by unknown
Post by Just Another Opinion
"Counterpoises" to isolate the antenna from ground. They are not long
enough
Post by Just Another Opinion
to be resonant radials on any band.
Before doing anything -- READ THE MANUAL!
http://www.cushcraft.com/support/pdf/r7.pdf
Your results may vary -- let the reader beware.
--
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
"Thierry" <Answer direct via http://www.astrosurf.com/lombry/post.htm>
Post by unknown
Hi,
I used one.
At ground level it needs many flexible radials burried into the ground
to
Post by Just Another Opinion
Post by unknown
give good results.
Then I placed it on top of a small tower 10m high without its flexible
radials, the result is much better.
I remember than R1ANF was on 20m, I call him in SSB only a few
seconds
Post by unknown
Post by Just Another Opinion
Post by unknown
using my TX barefoot, and I had my QSL !
This is not a proof that the R7 works well, but in all cases, there is
nothing to tell against it. This is probably one of the best
vertical
Post by unknown
on
Post by unknown
Post by Just Another Opinion
the
Post by unknown
place.
But try to place it in height, that will improve the radiation
pattern.
Post by unknown
Post by Just Another Opinion
Post by unknown
about radials : http://www.astrosurf.com/lombry/qsl-radials.htm
73
Thierry, ON4SKY
http://www.astrosurf.com/lombry/
Post by David Browne
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
Post by David Browne
thanks dave browne
---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.688 / Virus Database: 449 - Release Date: 18/05/2004
Richard Clark
2004-05-20 01:54:41 UTC
Permalink
On Wed, 19 May 2004 16:40:05 -0700, "Just Another Opinion"
Post by Just Another Opinion
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.
Post by Just Another Opinion
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
Just Another Opinion
2004-05-20 15:14:18 UTC
Permalink
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/html/Towertalk/2003-08/msg00059.html

AND http://dayton.akorn.net/pipermail/towertalk/2001-March/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
Post by Richard Clark
On Wed, 19 May 2004 16:40:05 -0700, "Just Another Opinion"
Post by Just Another Opinion
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.
Post by Just Another Opinion
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
Just Another Opinion
2004-05-20 16:29:12 UTC
Permalink
Richard, Thierry and the original poster

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

--
From one currently in the Cloaked Mode
Richard Clark
2004-05-20 16:48:29 UTC
Permalink
On Thu, 20 May 2004 08:14:18 -0700, "Just Another Opinion"
Repetition is both tedious and changes nothing.
Post by Just Another Opinion
The R7 is NOT a quarter wave vertical -- it is a half wave end
fed antenna.
Mantras soothe the soul certainly.
Post by Just Another Opinion
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.
Post by Just Another Opinion
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.
Post by Just Another Opinion
Do you know what is in the black box matching unit ??
Yes I do.
Post by Just Another Opinion
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).
Post by Just Another Opinion
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.
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.
Post by Just Another Opinion
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.
Post by Just Another Opinion
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.
Post by Just Another Opinion
mostly because folks treat the R7 like a quarter wave vertical -- which it isn't
Repetition again, quite boring now.
Post by Just Another Opinion
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.
http://lists.contesting.com/archives/html/Towertalk/2003-08/msg00059.html
"There is no grounded part in an R7 type antenna"

Which, of course, negates page one of the quoted manual above....
Post by Just Another Opinion
AND http://dayton.akorn.net/pipermail/towertalk/2001-March/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.
Post by Just Another Opinion
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?
Post by Just Another Opinion
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
Jim Kelley
2004-05-20 17:29:41 UTC
Permalink
Post by Richard Clark
On Thu, 20 May 2004 08:14:18 -0700, "Just Another Opinion"
Repetition is both tedious and changes nothing.
Post by Just Another Opinion
The R7 is NOT a quarter wave vertical -- it is a half wave end
fed antenna.
Mantras soothe the soul certainly.
Post by Just Another Opinion
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.
Post by Just Another Opinion
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
"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.
Post by Just Another Opinion
Do you know what is in the black box matching unit ??
Yes I do.
Post by Just Another Opinion
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).
Post by Just Another Opinion
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.
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.
Post by Just Another Opinion
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.
Post by Just Another Opinion
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.
Post by Just Another Opinion
mostly because folks treat the R7 like a quarter wave vertical -- which it isn't
Repetition again, quite boring now.
Post by Just Another Opinion
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.
http://lists.contesting.com/archives/html/Towertalk/2003-08/msg00059.html
"There is no grounded part in an R7 type antenna"
Which, of course, negates page one of the quoted manual above....
Post by Just Another Opinion
AND http://dayton.akorn.net/pipermail/towertalk/2001-March/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.
Post by Just Another Opinion
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?
Post by Just Another Opinion
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
Richard Clark
2004-05-20 17:44:51 UTC
Permalink
Post by Jim Kelley
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
Rick, K6RJ
2004-05-21 17:02:45 UTC
Permalink
Post by Richard Clark
On Thu, 20 May 2004 08:14:18 -0700, "Just Another Opinion"
Repetition is both tedious and changes nothing.
Post by Just Another Opinion
The R7 is NOT a quarter wave vertical -- it is a half wave end
fed antenna.
Mantras soothe the soul certainly.
Post by Just Another Opinion
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.
Post by Just Another Opinion
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
"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
Richard Clark
2004-05-21 20:02:19 UTC
Permalink
Post by Rick, K6RJ
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
Hi Rick,

Thank you for the follow-up. You are correct, and yes the pdf is a
poor, unsearchable copy as evidenced by your observations offered.

As far as this thread goes, I've seen testimony that it works/doesn't
work with radials - both ways. Such is the value of testimonials
where you can find any answer to suit any occasion.

I've seen testimonial "proof" that an eh works better than a standard
quarterwave, wherein the data clearly proved it didn't. The
testimonials dismissed the data (their own) as irrelevant.
Testimonial is fine and is occasionally called for. Testimonial as
proof is worthless.

I've offered data to this point of a "prohibition" on using radials.
The difference between 120 quarterwave or halfwave radials compared to
one short "counterpoise" barely tipped the meter at 1dB on the
performance side of the ledger. As for matching, I averred that
tuning may be impacted (I cannot imagine how it could be otherwise).
THAT is within the provence of Amateur radio service as a minimum
technical skill. THIS is a technical forum where design and data is
offered for examination. The remaining correspondence is confined to
the slow lane or the shoulder when a rhetorical axle is broken.

Frankly, this "prohibition" of no radials is more a design mandate,
not a papal bull. The site offered where we can find the actual
components of the "black box" displayed and laid out schematic style
offers an equal opportunity to redesign to allow radials. This
apparently is not within the skill-set of many, or arguably even
desired; however, it is not impossible (nor particularly difficult).

To this last point. I would offer that most of the interesting
correspondence (that isn't simply entertainment quality) is composed
of rather academic interests. Some of it is impractical in the
extreme and as absurd as fractals. More of it barely offers a
difference that would twitch an S Meter, or a Power meter. This does
not mean it lacks merit in its discussion because, let's face it, a
forum is built and survives on the vigor of debate. Clearly no one is
going to (legitimately) re-invent the dipole, so topics become rather
obtuse.

73's
Richard Clark, KB7QHC
Jean-Guy
2004-05-20 00:17:41 UTC
Permalink
Hi Dave, here is my 2 cents worth on the R-7. Purchased it second hand last
summer, had to fix it due to high SWR on all band except 10 meters. After
checking out antenna did find that the 12 meter trap was the problem, and
after fixing it , well it was time to mount it. The installation here is 12
feet about ground , mounted on the baby barn, nice and easy to work on it
from the roof of baby barn. Also did put 3 guy wires just under the 10 meter
trap. Antenna is performing a lot better than expected on dx and is holding
its own on 40 meters local and roughly 600 miles during the day, of course
all depends on probagation also. But i am extremly satisfied with the
antenna so far, and with guys on it, well, dont have to worry much about it
during strong winds, as they do have a tendancy to bend a bit. It is also in
close proximities to trees and stuff, but does not seem to bother the
antenna pattern at all and swr is what the book says.
this is my 2 cents worth.
thanks for reading.
de Jean-Guy/ve9buf
Post by David Browne
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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Bob Miller
2004-05-20 01:39:01 UTC
Permalink
Post by David Browne
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
Post by David Browne
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Tom Ring
2004-05-22 00:59:56 UTC
Permalink
Post by David Browne
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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Ok, I spoke to the designer this evening, and I'll pass on what I
learned. He was speaking fast, as he normally does, so I'm sure I
missed a lot. Roy can confirm that, and Roy can confirm that he handed
over another copy of his software to him just last week.

Per the designer

The R7 was built because he needed a multiband antenna in the fall of
90. The R5 was used as the base idea for the design. He worked on it
over late fall and winter 90/91. The antenna project was up and down 2
to 3 times a day at times.

The owner of Cushcraft heard of the backyard project in spring 1991, and
"asked" that it be brought to work. Tomorrow at the latest.

The antenna is not a half wave antenna, it is about a 3/8 wave antenna.
The impedance is approximately 250 ohms, and a roughly 4.5 to 1
transform is done. There is a series cap of 41 pF for 40m.

There are 7 radials of 49 inches, because Cushcraft had tons of 49 inch
5/8 whips for 2m. The R5 had 4, this needed more.

There is a false resonance on 75m or 80m, and if you put power into it
at that freq, you will burn up the matching system.

And, to end this argument, do not ever add radials to the system, and do
not remove any of the ones it comes with. It's a touchy match.

tom
K0TAR
Keyboard In The Noise
2004-05-23 15:14:41 UTC
Permalink
Golly Gee -- what happened to the great R7 radial debate ??? (:-(

Not one single reply to the excellent post below -- guess it did end the
argument (:-)

Thanks for the post Tom
-------------------------------------------------------
Post by Tom Ring
Ok, I spoke to the designer this evening, and I'll pass on what I
learned. He was speaking fast, as he normally does, so I'm sure I
missed a lot. Roy can confirm that, and Roy can confirm that he handed
over another copy of his software to him just last week.
Per the designer
The R7 was built because he needed a multiband antenna in the fall of
90. The R5 was used as the base idea for the design. He worked on it
over late fall and winter 90/91. The antenna project was up and down 2
to 3 times a day at times.
The owner of Cushcraft heard of the backyard project in spring 1991, and
"asked" that it be brought to work. Tomorrow at the latest.
The antenna is not a half wave antenna, it is about a 3/8 wave antenna.
The impedance is approximately 250 ohms, and a roughly 4.5 to 1
transform is done. There is a series cap of 41 pF for 40m.
There are 7 radials of 49 inches, because Cushcraft had tons of 49 inch
5/8 whips for 2m. The R5 had 4, this needed more.
There is a false resonance on 75m or 80m, and if you put power into it
at that freq, you will burn up the matching system.
And, to end this argument, do not ever add radials to the system, and do
not remove any of the ones it comes with. It's a touchy match.
tom
K0TAR
Bob Miller
2004-05-24 13:46:08 UTC
Permalink
On Sun, 23 May 2004 08:14:41 -0700, "Keyboard In The Noise"
Post by Keyboard In The Noise
Golly Gee -- what happened to the great R7 radial debate ??? (:-(
Not one single reply to the excellent post below -- guess it did end the
argument (:-)
Well, I found it interesting that the R7 is a 3/8 wave antenna, not a
1/2-waver. Which means radials might work as well as those 2-meter
whips/decouplers sticking out at the base.

Funny, I've never seen Cushcraft refer in their ads to their designs
being "1/2 wave." Maybe that's just a myth somebody started...

Bob
k5qwg
Post by Keyboard In The Noise
Thanks for the post Tom
-------------------------------------------------------
Post by Tom Ring
Ok, I spoke to the designer this evening, and I'll pass on what I
learned. He was speaking fast, as he normally does, so I'm sure I
missed a lot. Roy can confirm that, and Roy can confirm that he handed
over another copy of his software to him just last week.
Per the designer
The R7 was built because he needed a multiband antenna in the fall of
90. The R5 was used as the base idea for the design. He worked on it
over late fall and winter 90/91. The antenna project was up and down 2
to 3 times a day at times.
The owner of Cushcraft heard of the backyard project in spring 1991, and
"asked" that it be brought to work. Tomorrow at the latest.
The antenna is not a half wave antenna, it is about a 3/8 wave antenna.
The impedance is approximately 250 ohms, and a roughly 4.5 to 1
transform is done. There is a series cap of 41 pF for 40m.
There are 7 radials of 49 inches, because Cushcraft had tons of 49 inch
5/8 whips for 2m. The R5 had 4, this needed more.
There is a false resonance on 75m or 80m, and if you put power into it
at that freq, you will burn up the matching system.
And, to end this argument, do not ever add radials to the system, and do
not remove any of the ones it comes with. It's a touchy match.
tom
K0TAR
Keyboard In The Noise
2004-05-24 14:36:15 UTC
Permalink
Hi Bob -- see URL:
http://www.cushcraft.com/support/pdf/r5.pdf

Sez -- "Your R5 is a half wavelength vertical which does not require
traditional ground radials"
--
Keyboard In The Noise

Opinions are the cheapest commodities in the world. Author unknown but
"right on"
--------------------------------------------------
Post by Bob Miller
Funny, I've never seen Cushcraft refer in their ads to their designs
being "1/2 wave." Maybe that's just a myth somebody started...
Bob
k5qwg
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