Rohn 25G without guys, how high?
 

How high would you all feel comfortable about going with a Rohn 25G tower
without guys, with a 6-foot concrete base and a 2 meter / 440 gain
vertical antenna on top (e.g. Diamond X-700HNA)?

Rohn 25G without guys, how high?
 

i have been on 50' of rohn 25 unguyed to take down a tribander. it was in a
no wind zone (surrounded by very dense 60'+ pine trees). i didn't like it
and would not recommend it. the 'old' book shows a max of 40' with 1.5sq ft
of antenn in a 70mph wind zone with no ice... and drops down to 20' with
90mph winds plus ice.

"Rick (W-A-one-R-K-T)" wrote in message
.. .

How high would you all feel comfortable about going with a Rohn 25G tower
without guys, with a 6-foot concrete base and a 2 meter / 440 gain
vertical antenna on top (e.g. Diamond X-700HNA)?

Rohn 25G without guys, how high?
 

Dear Rick (WA1RKT):

It depends. Out where I live with nothing (such as trees and buildings)
to reduce the energy of the wind, I would not feel comfortable with more
than two sections of 25G. Three sections in an urban area with lots of
trees and buildings, and with no danger to life or property if the thing
blows down, might be reasonable.

The standard for such things (222G) adjusts the safety factor (though
not called that) depending on terrain and what is in the fall-over-radius.
Thus the information provided by Rohn provides only a starting point.

It depends. Tell us more.

73, Mac N8TT

--
J. Mc Laughlin; Michigan U.S.A.
Home:
"Rick (W-A-one-R-K-T)" wrote in message
.. .

How high would you all feel comfortable about going with a Rohn 25G tower
without guys, with a 6-foot concrete base and a 2 meter / 440 gain
vertical antenna on top (e.g. Diamond X-700HNA)?

Rohn 25G without guys, how high?
 

On Sun, 01 Jul 2007 14:07:54 +0000, Dave wrote:

i have been on 50' of rohn 25 unguyed to take down a tribander.

Wow. You're a better man than I am, Gunga Din. :-)

I actually wasn't planning on climbing it, rather planned on using one of
their hinge-over bases to raise and lower it when needed. I was thinking
of 40 feet, max.

To answer J's question... it's in a suburban setting on 2 acres of land,
and where the tower will be, if it fell over it would be all on my
property (i.e. no danger to neighbors or passersby). We're sufficiently
protected by trees such that only once in the 22 years I have lived here
have I seen winds of over about 40 MPH at below-the-treetops level (around
60-70 feet).

I have another Rohn 25G tower on the other end of the house that is
currently 40 feet, and I am in the process of adding another 10 feet for a
total of 50. It is guyed at the 30-foot level. I had to remove the top
section to add another 10-foot mid section, and now I'm in the process of
rasslin' the top section back into place (oh, so much fun). So, that'll
be 20 feet unguyed on top of 30 feet guyed. I'm trying to decide whether
I want to put a tribander on top of that or maybe get something light like
the Butternut Butterfly. I'm not a huge DX freak so don't really need a
full size multi-element 20-meter beam.

Rohn 25G without guys, how high?
 

sorry, think again... no hinge bases allowed on free standing towers. those
are only for guyed or bracketed towers. free standing towers must embed the
base section in concrete.


"Rick (W-A-one-R-K-T)" wrote in message
.. .
On Sun, 01 Jul 2007 14:07:54 +0000, Dave wrote:

i have been on 50' of rohn 25 unguyed to take down a tribander.

Wow. You're a better man than I am, Gunga Din. :-)

I actually wasn't planning on climbing it, rather planned on using one of
their hinge-over bases to raise and lower it when needed. I was thinking
of 40 feet, max.

To answer J's question... it's in a suburban setting on 2 acres of land,
and where the tower will be, if it fell over it would be all on my
property (i.e. no danger to neighbors or passersby). We're sufficiently
protected by trees such that only once in the 22 years I have lived here
have I seen winds of over about 40 MPH at below-the-treetops level (around
60-70 feet).

I have another Rohn 25G tower on the other end of the house that is
currently 40 feet, and I am in the process of adding another 10 feet for a
total of 50. It is guyed at the 30-foot level. I had to remove the top
section to add another 10-foot mid section, and now I'm in the process of
rasslin' the top section back into place (oh, so much fun). So, that'll
be 20 feet unguyed on top of 30 feet guyed. I'm trying to decide whether
I want to put a tribander on top of that or maybe get something light like
the Butternut Butterfly. I'm not a huge DX freak so don't really need a
full size multi-element 20-meter beam.

Rohn 25G without guys, how high?
 

On Sun, 01 Jul 2007 16:58:42 +0000, Dave wrote:

sorry, think again... no hinge bases allowed on free standing towers.

Hmmm ... OK, I guess I will have to be able to climb it...

I suppose I could install temporary guys while I'm up on it doing antenna
work, but in that location permanent guying wouldn't work too well...

free standing towers must embed the base section in concrete.

How about the BPC25G base plate (non-hinged)?

I already have a concrete base in place, 6 feet deep, intended for the
predecessor to the US Tower MA-series crank-up mast. The mast (and the
base, and the tower on the other end of the house) belonged to my father
when he lived with us, but he sold the mast many years ago, and the new
ones are a bit too pricey for me right now.

So, it's too late to embed the bottom section directly into the concrete,
at least in that location.

Rohn 25G without guys, how high?
 

On Sun, 01 Jul 2007 16:39:37 -0500, J. Mc Laughlin wrote:

What was your father's call-sign?

K4MH. He became a silent key about a year and a half ago.

Rohn 25G without guys, how high?
 

to quote the book 'pinned bases must not be used'. think about it, when
there are no guys the highest stress point is where the metal meets the
concrete. each leg must be held down by something at least as strong as it
is. there might be a way to drill holes for each leg and epoxy in a stub of
some kind, but that would be a job for a pro.

"Rick (W-A-one-R-K-T)" wrote in message
...
On Sun, 01 Jul 2007 16:58:42 +0000, Dave wrote:

sorry, think again... no hinge bases allowed on free standing towers.

Hmmm ... OK, I guess I will have to be able to climb it...

I suppose I could install temporary guys while I'm up on it doing antenna
work, but in that location permanent guying wouldn't work too well...

free standing towers must embed the base section in concrete.

How about the BPC25G base plate (non-hinged)?

I already have a concrete base in place, 6 feet deep, intended for the
predecessor to the US Tower MA-series crank-up mast. The mast (and the
base, and the tower on the other end of the house) belonged to my father
when he lived with us, but he sold the mast many years ago, and the new
ones are a bit too pricey for me right now.

So, it's too late to embed the bottom section directly into the concrete,
at least in that location.

Rohn 25G without guys, how high?
 

On Sun, 01 Jul 2007 16:39:37 -0500, J. Mc Laughlin wrote:

Dear Rick WA1RHT:... eventually Conn. will see same.

Ah, I see. I was wondering why the reference to Conn. :-)

It's actually RKT (in New Hampshire) not RHT.

The cryptic spelling in my From: line is an attempt to deter spammers, who
no doubt harvest this and other rec.radio.amateur forums for call signs,
add " to the end, and add them to their spam lists.

Of course any such attempt to deter spammers is likely doomed to failure
but I do the best I can... :-(

As for ice we actually do get ice from time to time here, but high winds
are rare.

Of course, all you need is once, I suppose...

Rohn 25G without guys, how high?
 

On Sun, 01 Jul 2007 20:44:45 +0000, Dave wrote:

to quote the book 'pinned bases must not be used'. think about it, when
there are no guys the highest stress point is where the metal meets the
concrete. each leg must be held down by something at least as strong as
it is.

Yup, makes sense.

Unfortunately the base is spaced out just a bit too far from the house to
be able to add a house brace that's strong enough. Why Dad did that I
can't quite figure out... of course, he had the mast at the time...

Also unfortunately, US Towers tells me that the bolt spacing on my base,
which was for a mast that was manufactured by a company that US Towers
apparently acquired years ago, is wrong for their current crop of crank-up
masts. :-( :-(

So, I guess I have a tower base that would hold up a (proper)
self-supporting tower through a hurricane, but I can't do anything with it. :-(

Rohn 25G without guys, how high?
 

On Sun, 01 Jul 2007 16:39:37 -0500, J. Mc Laughlin wrote:

Two sections above guys next to the house is pushing prudence. With a
clear area next to the proposed tower in the back, three sections with
just a VHF antenna seems reasonable in view of your description.

I'm curious why two sections above the guys, next to the house, is
marginal but three sections self-supporting out in the open seems OK.

Actually the three sections self-supporting would be as close to the house
on one end as the guyed tower is on the other end.

Perhaps the tribander on the guyed tower makes the difference, but in
truth I think the chances are fairly slim that I'll end up doing that. I
have two inverted vees and two NVIS dipoles, which together cover 160
through 40, which these days are the only HF bands that really hold my
interest... I never was much of a DX hound and with the Internet and
satellite phones, it doesn't seem like hardly anybody wants to pass any
traffic or run phone patches anymore. Perhaps when the sunspots get more
favorable I'll re-think the notion of the tribander but until then it's
probably pretty low on the priority list.

Rohn 25G without guys, how high?
 

Dear Rick WA1RHT:

You have received useful advice.

While you may not have seen serious wind nor serious ice, eventually
Conn. will see same.

Two sections above guys next to the house is pushing prudence. With a
clear area next to the proposed tower in the back, three sections with just
a VHF antenna seems reasonable in view of your description.

It is nice to see questions from actual radio amateurs who state their
call-sign. What was your father's call-sign? Good luck.

73, Mac N8TT

--
J. Mc Laughlin; Michigan U.S.A.
Home:
"Rick (W-A-one-R-K-T)" wrote in message
...
On Sun, 01 Jul 2007 16:58:42 +0000, Dave wrote:

sorry, think again... no hinge bases allowed on free standing towers.

Hmmm ... OK, I guess I will have to be able to climb it...

I suppose I could install temporary guys while I'm up on it doing antenna
work, but in that location permanent guying wouldn't work too well...

free standing towers must embed the base section in concrete.

How about the BPC25G base plate (non-hinged)?

I already have a concrete base in place, 6 feet deep, intended for the
predecessor to the US Tower MA-series crank-up mast. The mast (and the
base, and the tower on the other end of the house) belonged to my father
when he lived with us, but he sold the mast many years ago, and the new
ones are a bit too pricey for me right now.

So, it's too late to embed the bottom section directly into the concrete,
at least in that location.

Rohn 25G without guys, how high?
 

On Sun, 01 Jul 2007 16:52:04 -0400, "Rick (W-A-one-R-K-T)"
wrote:

my From: line is an attempt to deter spammers, who
no doubt harvest this and other rec.radio.amateur forums for call signs,

Hi Rick,

I've laid my return address out there bare for more than a dozen
years, and the amount of spam hardly compares to my other email
(professional and social) accounts (sometimes 40-60 in a day for them,
compared to one or two a month here).

73's
Richard Clark, KB7QHC

Rohn 25G without guys, how high?
 

I have fifty feet of 25G standing next to a pole barn... It is
bracketed to the eve at ~14 feet and free standing above that... It
has a gaggle of vhf/uhf stuff on it... It has withstood 80mph wind
gusts... It is a bit loosey goosey when you are at the top so I pull
some light rope up there when I climb up, and cinch it off to stop the
sway...

denny / k8do

Rohn 25G without guys, how high?
 

On Sun, 01 Jul 2007 15:20:54 -0400, "Rick (W-A-one-R-K-T)"
wrote:

On Sun, 01 Jul 2007 16:58:42 +0000, Dave wrote:

sorry, think again... no hinge bases allowed on free standing towers.

Hmmm ... OK, I guess I will have to be able to climb it...

I suppose I could install temporary guys while I'm up on it doing antenna
work, but in that location permanent guying wouldn't work too well...

free standing towers must embed the base section in concrete.

How about the BPC25G base plate (non-hinged)?

I already have a concrete base in place, 6 feet deep, intended for the
predecessor to the US Tower MA-series crank-up mast. The mast (and the
base, and the tower on the other end of the house) belonged to my father
when he lived with us, but he sold the mast many years ago, and the new
ones are a bit too pricey for me right now.

So, it's too late to embed the bottom section directly into the concrete,
at least in that location.
I have the early model Crank up mast (Wilson, CT-77) that I brought
with me from Ohio in 1993. No one would give me $400 for it! The top
section failed (overloaded with VHF-UHF stuff in 1980's while in a
guyed configuration. It twisted and developed a diagonal crease.

Some time in the late 1990's I restored the mast and built a home brew
base for it. With the top section removed it is about 55 feet.

I had an opportunity to examine a factory built erection base and I
felt too many compromises were made to keep it shippable. I was able
to acquire scrap steel from a local salvage yard. I mounted a 1/2"
steel plate (actually 2 1/4" pieces) about 20" x 30" on wide spread
1/2" J-Bolts embedded in 5 Yards of concrete (5 yards is overkill, but
that was the minimum charge so I elected to use it). I think they were
about 36" long. I feel the J-Bolts are the weakest part of the design.

I mounted an I-Beam vertically (about 12 feet tall) to the plate with
1/2" Grade 8 bolts and heavy angle iron to the base. I also mounted
the hinge plate for the mast to the plate. Then I fashioned a pulley
arrangement from the upright to raise & lower the tower.

The tower at the 23 foot mark with a Cushcraft A3S beam and a G800
Yaesu rotor is load enough to raise and lower. In that configuration a
ladder is still needed to reach the beam mounting bolts due to the
length of the antenna elements and the boom length.

The combination seems to handle the weather better at about the 45
foot mark so I seldom raise it above that.

I use an electric boat winch to raise & lower the mast extent ion. I
have been using a crank winch to raise & lower the tubular assembly.
Hopefully, I will get that converted to an electric winch sometime
this year. Age is catching up with me.

We have Hurricanes & Ice in North Carolina. However, the wind rarely
exceeds 80 mph in my area. I expect to lose the antenna some day but I
doubt the tower will fail.

Although I had an electric welder available I used nuts & bolts
because I felt my welding skills were suspect. I had a small back hoe
(Terra Mite) available for the digging & Heavy lifting.

I would do it again. But I would not consider it with a non
retractable mast.

John Ferrell W8CCW
"Life is easier if you learn to
plow around the stumps"

Rohn 25G without guys, how high?
 

Dear Rick: Sorry to have received the call-sign incorrectly. Your
Father's call does not ring any bells.

The main reason for two sections above a house bracket is because of the
significantly greater probability of greater wind pressure on the two
sections compared to three sections that start at ground level. You also
expect to have more effective area for the greater wind pressure to work on.

I have become convinced that the reason few urban TV/FM antennas and
Rohn 20 (no cross braces) towers fail is because of a dramatic reduction in
wind pressure up to about 35 feet above ground in a typical urban
environment.

The real limitation (for you) may turn out to be due to the building
code used in your area. When the time comes to have a serious antenna tower
for HF, do find a professional engineer licensed in your State who's advice
about how to satisfy the building code and 222G will be worth every penny
you pay to him or her.

Warm regards, Mac N8TT

P.S. My neighbor K8DO still does things that give me the willies. Even
when I was young, I sure would not climb 50 feet of un-guyed Rohn 25.
Medical school instills rather more "confidence" than engineering schools
do.
--
J. Mc Laughlin; Michigan U.S.A.
Home:
"Rick (W-A-one-R-K-T)" wrote in message
.. .
On Sun, 01 Jul 2007 16:39:37 -0500, J. Mc Laughlin wrote:

Two sections above guys next to the house is pushing prudence. With a
clear area next to the proposed tower in the back, three sections with
just a VHF antenna seems reasonable in view of your description.

I'm curious why two sections above the guys, next to the house, is
marginal but three sections self-supporting out in the open seems OK.

Actually the three sections self-supporting would be as close to the house
on one end as the guyed tower is on the other end.

Perhaps the tribander on the guyed tower makes the difference, but in
truth I think the chances are fairly slim that I'll end up doing that. I
have two inverted vees and two NVIS dipoles, which together cover 160
through 40, which these days are the only HF bands that really hold my
interest... I never was much of a DX hound and with the Internet and
satellite phones, it doesn't seem like hardly anybody wants to pass any
traffic or run phone patches anymore. Perhaps when the sunspots get more
favorable I'll re-think the notion of the tribander but until then it's
probably pretty low on the priority list.

Rohn 25G without guys, how high?
 

On Mon, 2 Jul 2007 19:52:24 -0500, "J. Mc Laughlin"
wrote:

Dear Rick: Sorry to have received the call-sign incorrectly. Your
Father's call does not ring any bells.

The main reason for two sections above a house bracket is because of the
significantly greater probability of greater wind pressure on the two
sections compared to three sections that start at ground level. You also
expect to have more effective area for the greater wind pressure to work on.

I have become convinced that the reason few urban TV/FM antennas and
Rohn 20 (no cross braces) towers fail is because of a dramatic reduction in
wind pressure up to about 35 feet above ground in a typical urban
environment.

The real limitation (for you) may turn out to be due to the building
code used in your area. When the time comes to have a serious antenna tower
for HF, do find a professional engineer licensed in your State who's advice
about how to satisfy the building code and 222G will be worth every penny
you pay to him or her.

Warm regards, Mac N8TT

P.S. My neighbor K8DO still does things that give me the willies. Even
when I was young, I sure would not climb 50 feet of un-guyed Rohn 25.
Medical school instills rather more "confidence" than engineering schools
do.

Shucks, I met him way before he became so conservative.

Rohn 25G without guys, how high?
 

On 2 Jul, 17:52, "J. Mc Laughlin" wrote:
Dear Rick: Sorry to have received the call-sign incorrectly. Your
Father's call does not ring any bells.

The main reason for two sections above a house bracket is because of the
significantly greater probability of greater wind pressure on the two
sections compared to three sections that start at ground level. You also
expect to have more effective area for the greater wind pressure to work on.

I have become convinced that the reason few urban TV/FM antennas and
Rohn 20 (no cross braces) towers fail is because of a dramatic reduction in
wind pressure up to about 35 feet above ground in a typical urban
environment.

The real limitation (for you) may turn out to be due to the building
code used in your area. When the time comes to have a serious antenna tower
for HF, do find a professional engineer licensed in your State who's advice
about how to satisfy the building code and 222G will be worth every penny
you pay to him or her.

Warm regards, Mac N8TT

P.S. My neighbor K8DO still does things that give me the willies. Even
when I was young, I sure would not climb 50 feet of un-guyed Rohn 25.
Medical school instills rather more "confidence" than engineering schools
do.
--
J. Mc Laughlin; Michigan U.S.A.
Home: "Rick (W-A-one-R-K-T)" wrote in message

.. .



On Sun, 01 Jul 2007 16:39:37 -0500, J. Mc Laughlin wrote:

Two sections above guys next to the house is pushing prudence. With a
clear area next to the proposed tower in the back, three sections with
just a VHF antenna seems reasonable in view of your description.

I'm curious why two sections above the guys, next to the house, is
marginal but three sections self-supporting out in the open seems OK.

Actually the three sections self-supporting would be as close to the house
on one end as the guyed tower is on the other end.

Perhaps the tribander on the guyed tower makes the difference, but in
truth I think the chances are fairly slim that I'll end up doing that. I
have two inverted vees and two NVIS dipoles, which together cover 160
through 40, which these days are the only HF bands that really hold my
interest... I never was much of a DX hound and with the Internet and
satellite phones, it doesn't seem like hardly anybody wants to pass any
traffic or run phone patches anymore. Perhaps when the sunspots get more
favorable I'll re-think the notion of the tribander but until then it's
probably pretty low on the priority list.- Hide quoted text -

- Show quoted text -

Hey Mac,
ask that medical neigbour of yours why a lot of disease of the
body are not encapsulated in their own little prison instead of
medics
resorting to the knife? I, like many, was born in the industrial era
where many caught T.B. and other disease and suffered from hunger.
In my case when I got T.B. the pollutants I breathed created a
calcinated shell around it thus rendering it harmless via prison.
Now a days we move to the knife or drugs too often where
accepting possesion of the disease is better by placing it in
quarantean..
Seems like surgeons also have information but also reject under the
"all is known"
mantra.
Art Unwin KB9MZ....XG

Rohn 25G without guys, how high?
 

Dear Neighbor Roger:

Oh my, and I clean forgot that the two of us fly little airplanes into
and out-of strange places. Perhaps it is just antenna people in this part
of Michigan. No. I am convinced that for DO it is the residue of surviving
in a factory and medical school.

Warm regards, Mac N8TT

--
J. Mc Laughlin; Michigan U.S.A.
Home:
"Roger (K8RI)" wrote in message
...
On Mon, 2 Jul 2007 19:52:24 -0500,
snip

P.S. My neighbor K8DO still does things that give me the willies. Even
when I was young, I sure would not climb 50 feet of un-guyed Rohn 25.
Medical school instills rather more "confidence" than engineering schools
do.

Shucks, I met him way before he became so conservative.

Rohn 25G without guys, how high?
 

On Tue, 03 Jul 2007 15:28:08 -0500, J. Mc Laughlin wrote:

Oh my, and I clean forgot that the two of us fly little airplanes into
and out-of strange places.

Oh, man, and to think I've been LISTENING to you daredevils... :-)

Rick Bonanza N122X (KASH)

Rohn 25G without guys, how high?
 

"Rick (W-A-one-R-K-T)" wrote in message
.. .

How high would you all feel comfortable about going with a Rohn 25G tower
without guys, with a 6-foot concrete base and a 2 meter / 440 gain
vertical antenna on top (e.g. Diamond X-700HNA)?


Probably not reccomended but a friend gave me one that had been up for 20
years that had an antenna package simliar(2m Ringo) to the one you mention
plus an HF tri-bander beam This antenna survived Hurricanne Hugo when
trees in the same yard didnt. Strange thing, we took the tribander down
first and the antenna swayed more after it was removed.

Jimmie

Rohn 25G without guys, how high?
 

On Sun, 8 Jul 2007 08:51:57 -0400, Jimmie D wrote:

Strange thing, we took the tribander down
first and the antenna swayed more after it was removed.
^^^^^^^
ITYM "tower"

Mass... Inertia... Mass moment of inertia...

Of course, if it ever starts swaying dramatically,
the same factors come into play.

Jonesy
--
Marvin L Jones | jonz | W3DHJ | linux
38.24N 104.55W | @ config.com | Jonesy | OS/2
*** Killfiling google posts: http://jonz.net/ng.htm

Rohn 25G without guys, how high?
 

"Allodoxaphobia" wrote in message
...
On Sun, 8 Jul 2007 08:51:57 -0400, Jimmie D wrote:

Strange thing, we took the tribander down
first and the antenna swayed more after it was removed.
^^^^^^^
ITYM "tower"

Mass... Inertia... Mass moment of inertia...

Of course, if it ever starts swaying dramatically,
the same factors come into play.

Jonesy
--
Marvin L Jones | jonz | W3DHJ | linux
38.24N 104.55W | @ config.com | Jonesy | OS/2
*** Killfiling google posts: http://jonz.net/ng.htm

Yes I meant "tower"

Rohn 25G without guys, how high?
 

Depending on how it is supported at the base and where it might be supported
somewhere in the middle - freestanding to 50 ft. Any other height needs to
be guyed!

"Jimmie D" wrote in message
...

"Allodoxaphobia" wrote in message
...
On Sun, 8 Jul 2007 08:51:57 -0400, Jimmie D wrote:

Strange thing, we took the tribander down
first and the antenna swayed more after it was removed.
^^^^^^^
ITYM "tower"

Mass... Inertia... Mass moment of inertia...

Of course, if it ever starts swaying dramatically,
the same factors come into play.

Jonesy
--
Marvin L Jones | jonz | W3DHJ | linux
38.24N 104.55W | @ config.com | Jonesy | OS/2
*** Killfiling google posts: http://jonz.net/ng.htm

Yes I meant "tower"