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)?

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
news

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)?

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
news

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)?

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.

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
news
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.

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.

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.

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
news
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.

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...

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. :-(