Author: sawyers@inav.net (Steven H Sawyers (na0ia))
Date: Sun May 4 15:06:17 2003
My comments/advise below: Yes - you can get wire ties that have Loops on each end of various lengths from a rebar supplier other than the "Home Depots" of the world. Usually come in large rolls of 5
Author: sawyers@inav.net (Steven H Sawyers (na0ia))
Date: Tue, 06 Aug 2002 22:07:37 -0500
Obviously they have had some turnover in their engineering department, and the engineer did not want to go look up the old calculations to see what was going on. Every company, which manufactures lif
Author: sawyers@inav.net (Steven H Sawyers (na0ia))
Date: Tue, 19 Mar 2002 19:55:02 -0600
Collins Radio did just this on a family of HF antennas in the fifities and sixties. The two booms meet at a point. Collins still has some in service at their Cedar Rapids HF Station. I work at Collin
Author: sawyers@inav.net (Steven H Sawyers (na0ia))
Date: Sat, 23 Mar 2002 19:28:51 -0600
We decided to refurbish the XA at our local club station and had cracks starting from the mast clamp holes exactly as your picture shows. Ours was 1/4 inch thick. We used the old one as a pattern and
Author: sawyers@inav.net (Steven H Sawyers (na0ia))
Date: Sat, 23 Mar 2002 22:56:07 -0600
Try www.mcmaster.com - they have lots of different u-bolts - will take a while to find, but their search engine and listings are amazing. Std Disclaimer - just a satified customer - about $400 a year
Author: sawyers@inav.net (Steven H Sawyers (na0ia))
Date: Fri, 09 Nov 2001 20:48:12 -0600
I would be a little suspicious of any existing foundation. But there are several ways to "skin this cat" How big was the dish? How does its wind load compare to your tower wind load. If they are comp
Author: sawyers@inav.net (Steven H Sawyers (n0yvy))
Date: Wed, 25 Aug 1999 05:04:57 -0500
The Rohn book says 25G will handle 8,450 pounds on each leg. I am assuming this means properly guyed with the guy spacing under 30'. The 90 MPH chart for a 190 foot tower shows a base reaction of 9,8
Author: sawyers@inav.net (Steven H Sawyers (n0yvy))
Date: Wed, 25 Aug 1999 23:30:33 -0500
My standard guying for Rohn 25 under 100' towers is 1/4" EHS. I even suggest a spread mount and 6 guys for anti-torque at the top. Increasing the guying does wonders for increasing the allowable ante
Author: sawyers@inav.net (Steven H. Sawyers n0yvy)
Date: Wed, 03 Mar 1999 20:57:01 -0600
1/4" on the top set for Rohn 25 is my preferred installation. Just don't mix sizes at one level. It makes the putting on proper tension a very difficult compromise. de n0yvy steve -- FAQ on WWW: http
Author: sawyers@inav.net (Steven H. Sawyers n0yvy)
Date: Wed, 03 Feb 1999 00:51:42 -0600
They are rated at 50 mph for their wind loads. I have spent a lot of time trying to help local hams engineer them in an 80 MPH wind district. We finally had to house bracket them and restrict elevati
Author: sawyers@inav.net (Steven H. Sawyers n0yvy)
Date: Wed, 10 Feb 1999 22:22:49 -0600
The guys must be equally spaced. One option to have your PE (and you need one for this) consider is four way guying. This will fit the guys into the corners of 150 foot square. This will give you abo
Author: sawyers@inav.net (Steven H. Sawyers n0yvy)
Date: Tue, 20 Oct 1998 21:49:58 -0500
I have not heard of the "Invisible Fence" (tm) or similar products causing HF interference. But I have heard of Amateur transmissions over-loading the front end of the dog collar and activating it on
Author: sawyers@inav.net (Steven H. Sawyers n0yvy)
Date: Sat, 05 Sep 1998 21:12:35 -0500
The easiest way I have found is to get about 3 wraps on each side then put some tension on it so I can take the wraps down together. if I don't do it this way, i wind up with a curve in the grip that
Author: sawyers@inav.net (Steven H. Sawyers n0yvy)
Date: Mon, 14 Sep 1998 09:33:05 -0500
Generally it is best not to but sharp bends in rebar. Minimum recommended bend radius is about 6 - 8 times the bar diameter. If you bend it sharper than you risk getting cracks in the outside edge. R
I have just finished telling a gentleman in the local club that his MA-550 is useless as a free standing antenna support in an 80 MPH wind district. He is not real happy with me. I am not real happy
Author: sawyers@inav.net (Steven H. Sawyers n0yvy)
Date: Thu, 06 Aug 1998 00:51:31 -0500
I apologize for the formatting of the previous message - have had some problems switching between Email programs. Reformatted message: I have just finished telling a gentleman in the local club that
Author: sawyers@inav.net (Steven H. Sawyers n0yvy)
Date: Fri, 21 Aug 1998 21:58:07 -0500
The limiting part of the Rohn standard installation in heights under a 100' is the guy strength. Keep the guy spacing around 25-30 feet, use the guy brackets - no torque arms - and use two top guys p
Author: sawyers@inav.net (Steven H. Sawyers n0yvy)
Date: Fri, 21 Aug 1998 22:46:06 -0500
They don't do any good and are a waste of time and money. I mean put a spreader mount or a "star mount" which provides two anchor points at the top of the tower for each guy anchor point. The two anc
Author: sawyers@inav.net (Steven H. Sawyers n0yvy)
Date: Sat, 22 Aug 1998 23:27:57 -0500
The problem is that there is no one simple formula - it is about 50 to 60 formulas and they all relate to one another. Generally on the shorter (less than 100 feet) you can safely increase the guy wi
Author: sawyers@inav.net (Steven H. Sawyers n0yvy)
Date: Sat, 22 Aug 1998 23:42:42 -0500
By the time the tower rotates far enough to have the torque arms do any good you have already used up most of the allowable lattice strength. Commercial installations don't use "torque arms" as hams