[TowerTalk] Rohn 25 installation

[Earl Morse]

The books that K1ZO mention are a great start.  Looking at the Rohn specs for standard off the shelf configurations will give you an idea of what can be done.  If your installation is atypical you might still be able to design something that will work in your case such as going to 4 guys or using elevated guys.  Guys have to go all around the tower as they pull against each other to hold the tower in place.  If you only use one or two then you run into the problem where it becomes ineffective as you push on a rope.  

If you have ever climbed an unguyed Rohn 20/25 tower above 30 feet you will notice the difference as it does sway.

Beyond that you may have to consider a self-supporting or crankup tower.

I was wondering why you were scrubbing and painting the sections if they were new?  New tower should have been hot dipped and ready to go up.  If you have to coat it I highly recommend the ZRC Cold galvanizing compound for older towers.  My Rohn 45 was a painted broadcast tower in a previous life.  I got it in chalky white and red/orange sections.  It was power washed then painted with the ZRC right over the existing paint.  It has been that nice battleship gray/silver and rust free at two QTHs for the last 20 years.  It's tough stuff.

Good luck with figuring out your installation.  You won't regret doing it right the first time.  Especially if that means not having your new yagi sitting in the living room with you, or worse, sitting in your neighbors living room.

Running high power in close proximity to your shack (1KW 30 feet above it) you will discover interesting phenomena such as computers resetting and meters moving on their own from the high RF fields.  Then we get into the RF exposure requirements for controlled areas (your property) and uncontrolled areas (your neighbors property).  See OET65 

http://transition.fcc.gov/Bureaus/Engineering_Technology/Documents/bulletins/oet65/oet65b.pdf

Good luck with figuring out your installation.  You won't regret doing it right the first time.  Especially if that means not having your new yagi sitting in the living room with you, or worse, sitting in your neighbors living room.


Earl
N8SS

> 
> 
> Hope you won?tmind answering a few questions/commenting?.
> 
> 
> I have purchased new60ft (10ft sections)  of Rohn 25 including a top section withrotor plate. It is in very good condition. I am in the process ofwashing it down with soap and water using  Scotch Brite Heavy DutyPads. I will be spraying it with Rustolium silver.
> 
> 
> I am going toinstall it on a tilt over, that I have to buy, and attach to housewith bracket/brackets. I want to initially put in 40ft of tower max,and would like to go un-guyed. If guyed, I will only be able to putguy wires pulling ?into the house? and attached to roof, andnothing going in the direction going opposite the bracket. The antennawill be a Mosley MP-33-N WARC. WT...29lbs, wind Surface...5.4 sqft...Wind Load EIA 80MPH 116.
> 
> 
> I live just outsideof Erie, Pa, which held the record for the snowiest city in the USthis winter with 137 inches. We also get severe thunderstorms inSummer, sometimes accompanied with high winds. I am concerned abouthow the antenna/tower will do in this environment, so am consideringonly going 30ft initially, and adding another 10 or 20 next Springafter I see how the 30Ft does this Summer and Winter.
> 
> 
> 1)    Assuming un-guyedand going a max of 50ft, if I can, what dimensions does the concretebase have to be and how long should I let it cure? Rebars?
> 
> 
> 2)    Recommendationsfor Rotor (Yeasu G-1000, TX2), Grounding, Lighting protection, Mast,
> Anything I forgot?Going to use Anti-seize on hardware. Self sealing tape forCoax/Connectors. New hardware for tower. Forgot the name, but a kindof paste to prevent corrosion on alum ant joints. From home depot.Will be at HRO in Del Wed and will price what I need. Where elsewould you call for pricing?
> 
> 
> 3)    Perrecommendations of  fellow  hams, I am getting LMR400 from Shireenand something flexible for Rotor Loop.
> 
> 
> May think of morelater, but these answers will be most helpful!!
> 
> 
> Few more facts:
> 
> 
> Station...KenwoodTS590...Going to Del Thurs to pick up a 1970 homebrew amp capable ofclose to legal limit. Do not own an Antenna Tuner. Do I needone...Mixed opinions there, but I think yes.  1:1 Balun? Mixed again.
> 
> 
> Antenna will beliterally turning above my head so coax run will be short. Currentantenna is an Alpha-Delta DXCC 10-80..Loads on lower 6mtr with 1:1SWR and very top of 160. flat also everywhere else. Run to Dipolewill be appox 175Ft. Hence recommendation for LMR400.
> 
> 
> 
> Mike Brumberger
> Amateur Radio Call... WB3DEL
> _______________________________________________
>